Network Working Group M. Suzuki
Request for Comments: 2383 NTT
Category: Informational August 1998
Network Working Group M. Suzuki
Request for Comments: 2383 NTT
Category: Informational August 1998
ST2+ over ATM Protocol Specification - UNI 3.1 Version
ATM上的ST2+协议规范-UNI 3.1版本
Status of this Memo
本备忘录的状况
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
本备忘录为互联网社区提供信息。它没有规定任何类型的互联网标准。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (1998). All Rights Reserved.
版权所有（C）互联网协会（1998年）。版权所有。
Abstract
摘要
This document specifies an ATM-based protocol for communication between ST2+ agents. The ST2+ over ATM protocol supports the matching of one hop in an ST2+ tree-structure stream with one ATM connection. In this document, ATM is a subnet technology for the ST2+ stream.
本文件规定了ST2+代理之间基于ATM的通信协议。ST2+over ATM协议支持将ST2+树结构流中的一个跃点与一个ATM连接相匹配。在本文中，ATM是ST2+流的子网技术。
The ST2+ over ATM protocol is designed to achieve resource-reservation communications across ATM and non-ATM networks, to extend the UNI 3.1/4.0 signaling functions, and to reduce the UNI 4.0 LIJ signaling limitations.
ST2+over ATM协议旨在实现ATM和非ATM网络之间的资源预留通信，扩展UNI 3.1/4.0信令功能，并减少UNI 4.0 LIJ信令限制。
The specifications of the ST2+ over ATM protocol consist of a revision of RFC 1819 ST2+ and specifications of protocol interaction between ST2+ and ATM on the user plane, management plane, and control plane which correspond to the three planes of the B-ISDN protocol reference model.
ATM上的ST2+协议规范包括RFC 1819 ST2+的修订版，以及与B-ISDN协议参考模型的三个平面相对应的用户平面、管理平面和控制平面上ST2+和ATM之间的协议交互规范。
The purpose of this document is to specify an ATM-based protocol for communication between ST2+ agents.
本文档旨在为ST2+代理之间的通信指定基于ATM的协议。
The ST2+ over ATM protocol is designed to support the matching of one hop in an ST2+ tree-structure stream with one ATM connection; it is not designed to support an entire ST2+ tree-structure stream with a point-to-multipoint ATM connection only.
ST2+over ATM协议旨在支持ST2+树结构流中的一个跃点与一个ATM连接的匹配；它的设计不支持仅具有点对多点ATM连接的整个ST2+树结构流。
Therefore, in this document, ATM is only a subnet technology for the ST2+ stream. This specification is designed to enable resource-reservation communications across ATM and non-ATM networks.
因此，在本文中，ATM只是ST2+流的子网技术。本规范旨在实现ATM和非ATM网络之间的资源预留通信。
o Enables resource-reservation communications across ATM and non-ATM networks.
o 启用跨ATM和非ATM网络的资源预留通信。
ATM native API supports resource-reservation communications only within an ATM network; it cannot support interworking with non-ATM networks. This is because
ATM本机API仅支持ATM网络内的资源预留通信；它不能支持与非ATM网络的互通。这是因为
- ATM native API cannot connect terminals without an ATM interface.
- ATM本机API无法连接没有ATM接口的终端。
- ATM native API does not support IP addressing and SAP (port) addressing systems.
- ATM本机API不支持IP寻址和SAP（端口）寻址系统。
o Extends UNI 3.1/4.0 signaling functions.
o 扩展UNI 3.1/4.0信令功能。
ST2+ SCMP supports MTU-size negotiation at all hops in an ST2+ tree-structure stream. UNI 3.1/4.0 supports only max CPCS_SDU (i.e., MTU) negotiation with the called party of a point-to-point call or with the first leaf of a point-to-multipoint call.
ST2+SCMP支持ST2+树结构流中所有跃点的MTU大小协商。UNI 3.1/4.0仅支持与点对点呼叫的被叫方或点对多点呼叫的第一个叶进行最大CPCS_SDU（即MTU）协商。
o Reduces UNI 4.0 LIJ signaling limitations.
o 减少UNI 4.0 LIJ信令限制。
The ST2+ over ATM protocol supports UNI 4.0 LIJ Call Identifier notification from the root to the leaf by using an ST2+ SCMP extension. LIJ Call Identifier discovery at the leaf is one of the major unsolved problems of UNI 4.0, and the ST2+ over ATM protocol provides a solution.
通过使用ST2+SCMP扩展，ATM上的ST2+协议支持从根到叶的UNI 4.0 LIJ呼叫标识符通知。叶上的LIJ呼叫标识符发现是UNI 4.0尚未解决的主要问题之一，而ATM上的ST2+协议提供了一个解决方案。
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not support the above feature. It will be supported by the UNI 3.1/4.0 version.
注：ATM上ST2+协议的UNI 3.1版本不支持上述功能。UNI 3.1/4.0版本将支持它。
The ST2+ over ATM protocol is designed to achieve the following goals.
ATM上的ST2+协议旨在实现以下目标。
o Specify protocol interaction between ST2+ [4] and ATM on the ATM Forum Private UNI 3.1/4.0 (Sb point) [10, 11].
o 在ATM论坛专用UNI 3.1/4.0（Sb点）[10,11]上指定ST2+[4]和ATM之间的协议交互。
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not support UNI 4.0. It will be supported by the UNI 3.1/4.0 version.
注：ATM上ST2+协议的UNI 3.1版本不支持UNI 4.0。UNI 3.1/4.0版本将支持它。
o Support ST2+ stream across ATM and non-ATM networks.
o 支持跨ATM和非ATM网络的ST2+流。
o Define one VC on the UNI corresponding to one ST2+ hop; this VC is not shared with other ST2+ hops, and also this ST2+ hop is not divided into multiple VCs.
o 在UNI上定义一个VC，对应一个ST2+跃点；此VC不与其他ST2+跃点共享，并且此ST2+跃点也不划分为多个VC。
o Support both SVC and PVC.
o 支持SVC和PVC。
o Not require any ATM specification changes.
o 不需要更改任何ATM规范。
o Coexist with RFC 1483 [16] IPv4 encapsulation.
o 与RFC 1483[16]IPv4封装共存。
o Coexist with RFC 1577 [17] ATMarp.
o 与RFC 1577[17]ATMarp共存。
o Coexist with RFC 1755 [18] ATM signaling for IPv4.
o 与IPv4的RFC 1755[18]ATM信令共存。
o Coexist with NHRP [19].
o 与NHRP共存[19]。
Because ST2+ is independent of both routing and IP address resolution protocols, the ST2+ over ATM protocol does not specify the following protocols.
因为ST2+独立于路由和IP地址解析协议，所以ATM上的ST2+协议不指定以下协议。
o IP-ATM address resolution protocol
o IP-ATM地址解析协议
o Routing protocol
o 路由协议
Because the ST2+ over ATM protocol is specified for the UNI, it is independent of:
由于ATM上的ST2+协议是为UNI指定的，因此它独立于：
o NNI protocol
o NNI协议
o Router/switch architecture
o 路由器/交换机体系结构
The ST2+ over ATM protocol specifies the interaction between ST2+ and ATM on the user, management, and control planes, which correspond to the three planes in ITU-T Recommendation I.321 B-ISDN Protocol Reference Model [14].
ATM上的ST2+协议规定了用户、管理和控制平面上ST2+和ATM之间的交互，这三个平面对应于ITU-T建议I.321 B-ISDN协议参考模型中的三个平面[14]。
The user plane specifies the rules for encapsulating the ST2+ Data PDU into the AAL5 [15] PDU. An user plane protocol stack is shown in Fig. 2.1.
用户平面指定将ST2+数据PDU封装到AAL5[15]PDU中的规则。用户平面协议栈如图2.1所示。
+---------------------------------+
| RFC 1819 ST2+ |
| (ST2+ Data) |
+---------------------------------+ Point of ST2+ over ATM
|/////////////////////////////////| <--- protocol specification of
+---------------------------------+ user plane
| |
| |
| I.363.5 |
| |
| AAL5 |
| |
| |
+---------------------------------+
| I.361 ATM |
+---------------------------------+
| PHY |
+----------------+----------------+
| UNI
+--------||-------
+---------------------------------+
| RFC 1819 ST2+ |
| (ST2+ Data) |
+---------------------------------+ Point of ST2+ over ATM
|/////////////////////////////////| <--- protocol specification of
+---------------------------------+ user plane
| |
| |
| I.363.5 |
| |
| AAL5 |
| |
| |
+---------------------------------+
| I.361 ATM |
+---------------------------------+
| PHY |
+----------------+----------------+
| UNI
+--------||-------
Fig. 2.1: User plane protocol stack.
图2.1：用户平面协议栈。
An example of interworking from an ATM network to an IEEE 802.X LAN is shown in Fig. 2.2.
图2.2显示了从ATM网络到IEEE 802.X LAN的互通示例。
ST2+ ST2+ ST2+
Origin ATM Cloud Intermediate Agent Target
+---------+ +---------+
| AP |--------------------------------------------->| AP |
+---------+ +-------------------+ +---------+
|ST2+ Data|------------------>| RFC 1819 ST2+ Data|----->|ST2+ Data|
+---------+ +---------+---------+ +---------+
|I.363 AAL|------------------>|I.363 AAL| SNAP |----->| SNAP |
+---------+ +---------+ +---------+---------+ +---------+
|I.361 ATM|--->|I.361 ATM|--->|I.361 ATM| LLC |----->| LLC |
+---------+ +---------+ +---------+---------+ +---------+
| | | | | |IEEE802.X| |IEEE802.X|
| PHY |--->| PHY |--->| PHY | & 802.1p|----->| & 802.1p|
+---------+ +---------+ +---------+---------+ +---------+
ST2+ ST2+ ST2+
Origin ATM Cloud Intermediate Agent Target
+---------+ +---------+
| AP |--------------------------------------------->| AP |
+---------+ +-------------------+ +---------+
|ST2+ Data|------------------>| RFC 1819 ST2+ Data|----->|ST2+ Data|
+---------+ +---------+---------+ +---------+
|I.363 AAL|------------------>|I.363 AAL| SNAP |----->| SNAP |
+---------+ +---------+ +---------+---------+ +---------+
|I.361 ATM|--->|I.361 ATM|--->|I.361 ATM| LLC |----->| LLC |
+---------+ +---------+ +---------+---------+ +---------+
| | | | | |IEEE802.X| |IEEE802.X|
| PHY |--->| PHY |--->| PHY | & 802.1p|----->| & 802.1p|
+---------+ +---------+ +---------+---------+ +---------+
Fig. 2.2: Example of interworking from an ATM network to an IEEE 802.X LAN.
图2.2：从ATM网络到IEEE 802.X LAN的互通示例。
The ATM cell supports priority indication using the CLP field; indication is also supported by the ST2+ Data PDU by using the Pri field. It may be feasible to map these fields to each other. The ST2+ over ATM protocol specifies an optional function that maps the Pri field in the ST header to the CLP field in the ATM cell. However, implementors should note that current ATM standardization tends not to support tagging.
ATM信元支持使用CLP字段的优先级指示；通过使用Pri字段，ST2+数据PDU也支持指示。将这些字段相互映射可能是可行的。ST2+over ATM协议指定一个可选功能，将ST报头中的Pri字段映射到ATM信元中的CLP字段。然而，实施者应该注意，当前的ATM标准化倾向于不支持标记。
The management plane specifies the Null FlowSpec, the Controlled-Load Service [5] FlowSpec, and the Guaranteed Service [6] FlowSpec mapping rules [8] for UNI 3.1 traffic management. A management plane protocol stack is shown in Fig. 2.3.
管理平面为UNI 3.1流量管理指定空FlowSpec、受控负载服务[5]FlowSpec和保证服务[6]FlowSpec映射规则[8]。管理平面协议栈如图2.3所示。
+---------------------------------+
| Null FlowSpec |
|Controlled-Load Service FlowSpec |
| Guaranteed Service FlowSpec |
+---------------------------------+ Point of ST2+ over ATM
|/////////////////////////////////| <--- protocol specification of
+---------------------------------+ management plane
| |
| UNI 3.1 |
| |
| |
| Traffic Management |
| |
| |
| VBR/UBR |
| |
+---------------------------------+
+---------------------------------+
| Null FlowSpec |
|Controlled-Load Service FlowSpec |
| Guaranteed Service FlowSpec |
+---------------------------------+ Point of ST2+ over ATM
|/////////////////////////////////| <--- protocol specification of
+---------------------------------+ management plane
| |
| UNI 3.1 |
| |
| |
| Traffic Management |
| |
| |
| VBR/UBR |
| |
+---------------------------------+
Fig. 2.3: Management plane protocol stack.
图2.3：管理平面协议栈。
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not support Guaranteed Services. It will be supported by the UNI 3.1/4.0 version.
注：ATM上ST2+协议的UNI 3.1版本不支持保证服务。UNI 3.1/4.0版本将支持它。
The ST2+ over ATM protocol specifies the ST FlowSpec format for the Integrated Services. Basically, FlowSpec parameter negotiation, except for the MTU, is not supported. This is because, in the ST2+ environment, negotiated FlowSpec parameters are not always unique to each target. The current ATM standard does not support heterogeneous QoS to receivers.
ATM上的ST2+协议规定了综合业务的ST FlowSpec格式。基本上，除了MTU，不支持FlowSpec参数协商。这是因为，在ST2+环境中，协商的FlowSpec参数对于每个目标并不总是唯一的。当前的ATM标准不支持对接收器的异构QoS。
The ST2+ over ATM protocol supports FlowSpec changes by using the CHANGE message (RFC 1819, Section 4.6.5) if the I-bit in the CHANGE message is set to one and if the CHANGE message affects all targets in the stream. This is because the UNI 3.1 does not support QoS changes. The ST2+ over ATM protocol supports FlowSpec changes by releasing old ATM connections and establishing new ones.
如果更改消息中的I位设置为1，并且更改消息影响流中的所有目标，则通过使用更改消息（RFC 1819，第4.6.5节），ST2+over ATM协议支持FlowSpec更改。这是因为UNI 3.1不支持QoS更改。ST2+over ATM协议通过释放旧的ATM连接并建立新的连接来支持FlowSpec更改。
The ST2+ over ATM protocol does not support stream preemption (RFC 1819, Section 6.3). This is because the Integrated Services FlowSpec does not support the concept of precedence.
ATM上的ST2+协议不支持流抢占（RFC 1819，第6.3节）。这是因为集成服务流程规范不支持优先级的概念。
It does not support the ST2+ FlowSpec (RFC 1819, Section 9.2). ST2+ FlowSpec specifies useful services, but requires a datalink layer to support heterogeneous QoS to receivers. The current ATM standard does not support heterogeneous QoS to receivers.
它不支持ST2+流程规范（RFC 1819，第9.2节）。ST2+FlowSpec指定了有用的服务，但需要数据链路层来支持接收器的异构QoS。当前的ATM标准不支持对接收器的异构QoS。
The control plane specifies the rules for encapsulating the ST2+ SCMP PDU into the AAL5 [15] PDU, the relationship between ST2+ SCMP and PVC management for ST2+ data, and the protocol interaction between ST2+ SCMP and UNI 3.1 signaling [10]. A control plane protocol stack is shown in Fig. 2.4.
控制平面规定了将ST2+SCMP PDU封装到AAL5[15]PDU中的规则、ST2+SCMP和ST2+数据PVC管理之间的关系以及ST2+SCMP和UNI 3.1信令之间的协议交互[10]。控制平面协议栈如图2.4所示。
+---------------------------------+
| RFC 1819 ST2+ |
| (ST2+ SCMP) |
+---------------------------------+ Point of ST2+ over ATM
|/////////////////////////////////| <--- protocol specification of
+------------+---+----------------+ control plane
| IEEE 802 | |UNI3.1 Signaling|
| SNAP | +----------------+
+------------+ | Q.2130 SSCF |
| ISO 8802-2 | +----------------+
| LLC Type1 | | Q.2110 SSCOP |
+------------+ +----------------+
| I.363.5 AAL5 |
+---------------------------------+
| I.361 ATM |
+---------------------------------+
| PHY |
+----------------+----------------+
| UNI
+--------||-------
+---------------------------------+
| RFC 1819 ST2+ |
| (ST2+ SCMP) |
+---------------------------------+ Point of ST2+ over ATM
|/////////////////////////////////| <--- protocol specification of
+------------+---+----------------+ control plane
| IEEE 802 | |UNI3.1 Signaling|
| SNAP | +----------------+
+------------+ | Q.2130 SSCF |
| ISO 8802-2 | +----------------+
| LLC Type1 | | Q.2110 SSCOP |
+------------+ +----------------+
| I.363.5 AAL5 |
+---------------------------------+
| I.361 ATM |
+---------------------------------+
| PHY |
+----------------+----------------+
| UNI
+--------||-------
Fig. 2.4: Control plane protocol stack.
图2.4：控制平面协议栈。
The ST2+ over ATM protocol does not cover a VC (SVC/PVC) that transfers ST2+ SCMP. VCs for IPv4 transfer may be used for ST2+ SCMP transfer, and implementations may provide particular VCs for ST2+ SCMP transfer. Selection of these VCs depends on the implementation.
ATM上的ST2+协议不包括传输ST2+SCMP的VC（SVC/PVC）。IPv4传输的VCs可用于ST2+SCMP传输，并且实施方案可为ST2+SCMP传输提供特定的VCs。这些VCs的选择取决于实施情况。
Implementors should note that when ST2+ data and SCMP belong to a stream, the routing directions on the ST2+ layer must be the same. Implementors should also note that ST2+ and IPv4 directions for routing to the same IP destination address are not always the same.
实现者应该注意，当ST2+数据和SCMP属于一个流时，ST2+层上的路由方向必须相同。实现者还应该注意，ST2+和IPv4路由到同一IP目标地址的方向并不总是相同的。
The ST2+ over ATM protocol supports both SVC and PVC for ST2+ Data PDU transfer. If SVC is used, the ST2+ and ATM layers establish a connection sequentially by using respectively ST2+ SCMP and UNI 3.1 signaling. An example of ST2+ SCMP and UNI 3.1 signaling message flows for establishing and releasing of ST2+ data connections is shown in Fig. 2.5, where (S) means an ST2+ entity and (Q) means a UNI 3.1 signaling entity.
ATM上的ST2+协议支持SVC和PVC用于ST2+数据PDU传输。如果使用SVC，则ST2+和ATM层分别使用ST2+SCMP和UNI 3.1信令顺序建立连接。图2.5显示了用于建立和释放ST2+数据连接的ST2+SCMP和UNI 3.1信令消息流的示例，其中（S）表示ST2+实体，（Q）表示UNI 3.1信令实体。
ATM SW ATM SW
+------------+ UNI +----+ NNI +----+ UNI +------------+
____|Intermediate|--||--| \/ |______| \/ |--||--|Intermediate|____
| (Upstream) | | /\ | | /\ | |(Downstream)|
+------------+ +----+ +----+ +------------+
SCMP
------->(S)<------------------------------------------>(S)<-------
\ UNI Sig. UNI Sig. /
CONNECT | (Q)<--------->(Q)<-------->(Q)<--------->(Q) |
-------->| |
ACK <----|--------------------CONNECT------------------>| CONNECT
|<---------------------ACK---------------------|-------->
| |<--- ACK
| | ACCEPT
| |<--------
|<-------------------ACCEPT--------------------|---> ACK
|----------------------ACK-------------------->|
| |
|->|----SETUP--->| | | |
| |<-CALL PROC--|----------->|----SETUP--->|->|
| | | |<----CONN----|<-|
ACCEPT | |<----CONN----|<-----------|--CONN ACK-->|->|
<--------|<-|--CONN ACK-->| | | |
ACK ---->| |
| |
-------\ |--------------------------------------------\ |-------\
>| ST2+ Data >| >
-------/ |--------------------------------------------/ |-------/
| |
DISCONN | |
-------->| |
ACK <----|-------------------DISCONNECT---------------->|
|<---------------------ACK---------------------|
| |
|->|---RELEASE-->| | | |
|<-|<--REL COMP--|----------->|---RELEASE-->|->| DISCONN
| | | |<--REL COMP--|<-|-------->
| |<--- ACK
ATM SW ATM SW
+------------+ UNI +----+ NNI +----+ UNI +------------+
____|Intermediate|--||--| \/ |______| \/ |--||--|Intermediate|____
| (Upstream) | | /\ | | /\ | |(Downstream)|
+------------+ +----+ +----+ +------------+
SCMP
------->(S)<------------------------------------------>(S)<-------
\ UNI Sig. UNI Sig. /
CONNECT | (Q)<--------->(Q)<-------->(Q)<--------->(Q) |
-------->| |
ACK <----|--------------------CONNECT------------------>| CONNECT
|<---------------------ACK---------------------|-------->
| |<--- ACK
| | ACCEPT
| |<--------
|<-------------------ACCEPT--------------------|---> ACK
|----------------------ACK-------------------->|
| |
|->|----SETUP--->| | | |
| |<-CALL PROC--|----------->|----SETUP--->|->|
| | | |<----CONN----|<-|
ACCEPT | |<----CONN----|<-----------|--CONN ACK-->|->|
<--------|<-|--CONN ACK-->| | | |
ACK ---->| |
| |
-------\ |--------------------------------------------\ |-------\
>| ST2+ Data >| >
-------/ |--------------------------------------------/ |-------/
| |
DISCONN | |
-------->| |
ACK <----|-------------------DISCONNECT---------------->|
|<---------------------ACK---------------------|
| |
|->|---RELEASE-->| | | |
|<-|<--REL COMP--|----------->|---RELEASE-->|->| DISCONN
| | | |<--REL COMP--|<-|-------->
| |<--- ACK
Fig. 2.5: Example of ST2+ SCMP and UNI 3.1 signaling message flows.
图2.5:ST2+SCMP和UNI 3.1信令消息流的示例。
UNI 3.1/4.0 specifies PVC, point-to-point SVC, and point-to-multipoint SVC as VC styles. However, in actual ATM network environments, especially public ATM WANs, only PVC and bi-directional point-to-point SVC may be supported. To support the diverse VC styles, the ST2+ over ATM protocol supports the following VC styles for ST2+ Data PDU transfer.
UNI 3.1/4.0将PVC、点对点SVC和点对多点SVC指定为VC样式。然而，在实际的ATM网络环境中，尤其是在公共ATM广域网中，只能支持PVC和双向点对点SVC。为了支持多种VC样式，ST2+over ATM协议支持以下用于ST2+数据PDU传输的VC样式。
o PVC
o 聚氯乙烯
o Reuse of reverse channel of bi-directional point-to-point SVC that is used by existing stream.
o 重用现有流使用的双向点到点SVC的反向通道。
o Point-to-point SVC initiated from upstream side.
o 从上游侧启动点对点SVC。
o Point-to-multipoint SVC initiated from upstream side.
o 从上游侧启动点对多点SVC。
o Point-to-point SVC initiated from downstream side.
o 从下游侧启动点对点SVC。
o Point-to-multipoint SVC initiated from downstream side (LIJ).
o 从下游侧（LIJ）启动点对多点SVC。
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not support LIJ. LIJ will be supported by the UNI 3.1/4.0 version.
注：ATM上ST2+协议的UNI 3.1版本不支持LIJ。LIJ将由UNI 3.1/4.0版本支持。
The second style is needed in environments supporting bi-directional point-to-point SVC only. The selection of PVC and SVC styles in the ST2+ agent is based on preconfigured implementation-dependent rules.
在仅支持双向点对点SVC的环境中需要第二种样式。ST2+代理中PVC和SVC样式的选择基于预配置的依赖于实现的规则。
SVC supports both upstream and downstream call initiation styles. Implementors should note that this is independent of the sender-oriented and receiver-oriented ST2+ stream-building process (RFC 1819, Section 4.1.1). This is because the ST2+ over ATM protocol specifies the process for establishing ST2+ data hops on the UNI, and because the ST2+ stream building process belongs to another layer. The SVC initiation side should be determined based on the operational and billing policies between ST2+ agents; this is basically independent of the sender-oriented and receiver-oriented ST2+ stream-building process.
SVC支持上游和下游调用启动样式。实施者应注意，这独立于面向发送方和面向接收方的ST2+流构建过程（RFC 1819，第4.1.1节）。这是因为ATM上的ST2+协议指定了在UNI上建立ST2+数据跳的过程，并且因为ST2+流构建过程属于另一层。SVC启动端应根据ST2+代理之间的操作和计费策略确定；这基本上独立于面向发送方和面向接收方的ST2+流构建过程。
An example of ST2+ SCMP interworking is shown in Fig. 2.6.
图2.6显示了ST2+SCMP互通的示例。
_____
/ \
(Origin )
\ /
A ~~|~~ A
| = | UNI Signaling
| | |
| +-+-+ V
| | X | ATM SW
| +-+-+ A
SCMP | | | NNI Signaling
| +-+-+ V
| | X | ATM SW
| +-+-+ A
| | |
| = | UNI Signaling
V | V
+-----+------+ IEEE 802.X & 802.1p
| |<---------------------+
|Intermediate|--------------------+ |
| |<-----------------+ | |
+------------+ L2 Signaling| | |
A | A | | |
| = | UNI Signaling | | | SCMP
| | | | | |
| +-+-+ V | | |
| | X | ATM SW V | |
| +-+-+ A +---+-|-+
SCMP | | | NNI Signaling | \ /| |
| +-+-+ V | X | |LAN SW
| | X | ATM SW | / \| |
| +-+-+ A +---+-|-+
| | | A | |
| = | UNI Signaling | | |
V __|__ V V_|_V
/ \ / \
(Target ) (Target )
\ / \ /
~~~~~ ~~~~~
_____
/ \
(Origin )
\ /
A ~~|~~ A
| = | UNI Signaling
| | |
| +-+-+ V
| | X | ATM SW
| +-+-+ A
SCMP | | | NNI Signaling
| +-+-+ V
| | X | ATM SW
| +-+-+ A
| | |
| = | UNI Signaling
V | V
+-----+------+ IEEE 802.X & 802.1p
| |<---------------------+
|Intermediate|--------------------+ |
| |<-----------------+ | |
+------------+ L2 Signaling| | |
A | A | | |
| = | UNI Signaling | | | SCMP
| | | | | |
| +-+-+ V | | |
| | X | ATM SW V | |
| +-+-+ A +---+-|-+
SCMP | | | NNI Signaling | \ /| |
| +-+-+ V | X | |LAN SW
| | X | ATM SW | / \| |
| +-+-+ A +---+-|-+
| | | A | |
| = | UNI Signaling | | |
V __|__ V V_|_V
/ \ / \
(Target ) (Target )
\ / \ /
~~~~~ ~~~~~
Fig. 2.6: Example of ST2+ SCMP interworking.
图2.6:ST2+SCMP互通示例。
To specify the ST2+ over ATM protocol, the functions in RFC 1819 ST2+ must be extended to support ATM. However, it is difficult for the current ATM standard to support part of the specifications in RFC 1819 ST2+. This section specifies the extended, restricted, unsupported, and modified functions in RFC 1819 ST2+. Errata for RFC 1819 appears in Appendix A.
要指定ATM上的ST2+协议，必须扩展RFC 1819 ST2+中的功能以支持ATM。然而，目前的ATM标准很难支持RFC1819 ST2+中的部分规范。本节指定RFC 1819 ST2+中的扩展、限制、不支持和修改函数。RFC 1819的勘误表见附录A。
The ST2+ over ATM protocol specifies the ST FlowSpec format for the Integrated Services. Basically, FlowSpec parameter negotiation, except for the MTU, is not supported. The ST2+ intermediate agent and the target decide whether to accept or refuse the FlowSpec parameters, except for the MTU. Therefore, each of the FlowSpec parameter values other than MTU is the same at each target in the stream.
ATM上的ST2+协议规定了综合业务的ST FlowSpec格式。基本上，除了MTU，不支持FlowSpec参数协商。ST2+中间代理和目标决定是否接受或拒绝FlowSpec参数，MTU除外。因此，流中每个目标处除MTU之外的每个FlowSpec参数值都相同。
The format of the ST FlowSpec for the Controlled-Load Service is shown in Fig. 3.1.
受控负载服务的ST FlowSpec格式如图3.1所示。
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PCode = 1 | PBytes = 36 | ST FS Ver = 8 | 0(unused) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ver=0 | 0(reserved) | Overall Length = 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SVC Number |0| 0(reserved) | SVC Length = 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Param Num = 127| Flags = 0 | Param Length = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Bucket Rate [r] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Bucket Size [b] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Data Rate [p] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum Policed Unit [m] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Packet Size [M] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PCode = 1 | PBytes = 36 | ST FS Ver = 8 | 0(unused) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ver=0 | 0(reserved) | Overall Length = 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SVC Number |0| 0(reserved) | SVC Length = 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Param Num = 127| Flags = 0 | Param Length = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Bucket Rate [r] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Bucket Size [b] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Data Rate [p] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum Policed Unit [m] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Packet Size [M] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Fig. 3.1: Format of ST FlowSpec for Controlled-Load Service.
图3.1：受控负载服务的ST FlowSpec格式。
The PCode field identifies common SCMP elements. The PCode value for the ST2+ FlowSpec is 1.
PCode字段标识常见的SCMP元素。ST2+FlowSpec的PCode值为1。
The PBytes field for the Controlled-Load Service is 36 bytes.
受控加载服务的PBytes字段为36字节。
The ST FS Ver (ST FlowSpec Version) field identifies the ST FlowSpec version. The ST FlowSpec version number for the Integrated Services is 8.
ST FS版本（ST FlowSpec版本）字段标识ST FlowSpec版本。集成服务的ST FlowSpec版本号为8。
The Ver (Message Format Version) field identifies the Integrated Services FlowSpec message format version. The current version is zero.
Ver（消息格式版本）字段标识Integrated Services FlowSpec消息格式版本。当前版本为零。
The Overall Length field for the Controlled-Load Service is 7 words.
受控负载服务的总长度字段为7个字。
The SVC Number (Service ID Number) field identifies the Integrated Services. If the Integrated Services FlowSpec appears in the CONNECT or CHANGE message, the value of the SVC Number field is 1. If it appears in the ACCEPT, NOTIFY, or STATUS-RESPONSE message, the value of the SVC Number field is 5.
SVC编号（服务ID编号）字段标识集成服务。如果Integrated Services FlowSpec出现在CONNECT或CHANGE消息中，则SVC Number字段的值为1。如果它出现在接受、通知或状态响应消息中，则SVC编号字段的值为5。
The SVC Length (Service-specific Data Length) field for the Controlled-Load Service is 6 words.
受控负载服务的SVC长度（服务特定数据长度）字段为6个字。
The Param Num (Parameter Number) field is 127.
Param Num（参数编号）字段为127。
The Flags (Per-parameter Flags) field is zero.
标志（每个参数标志）字段为零。
The Param Length (Length of Per-parameter Data) field is 5 words.
参数长度（每个参数数据的长度）字段为5个字。
Definitions of the Token Bucket Rate [r], the Token Bucket Size [b], the Peak Data Rate [p], the Minimum Policed Unit [m], and the Maximum Packet Size [M] fields are given in [5]. See section 5 of [5] for details.
[5]中给出了令牌桶速率[r]、令牌桶大小[b]、峰值数据速率[p]、最小策略单元[m]和最大数据包大小[m]字段的定义。详见[5]第5节。
The ST2+ agent, that creates the FlowSpec element in the SCMP message, must assign valid values to all fields. The other agents must not modify any values in the element.
在SCMP消息中创建FlowSpec元素的ST2+代理必须为所有字段分配有效值。其他代理不能修改元素中的任何值。
The MaxMsgSize field in the CONNECT message is assigned by the origin or the intermediate agent acting as origin, and updated by each agent based on the MTU value of the datalink layer.
CONNECT消息中的MaxMsgSize字段由源或作为源的中间代理分配，并由每个代理基于数据链路层的MTU值进行更新。
The negotiated value of MaxMsgSize is set back to the origin or the intermediate agent acting as origin using the [M] field and the MaxMsgSize field in the ACCEPT message that corresponds to the CONNECT message.
MaxMsgSize的协商值通过使用[M]字段和与CONNECT消息对应的ACCEPT消息中的MaxMsgSize字段设置回原点或充当原点的中间代理。
In the original definition of the Controlled-Load Service, the value of the [m] field must be less than or equal to the value of the [M] field. However, in the ST FlowSpec for the Controlled-Load Service, if the value of the [m] field is more than that of the [M] field, the value of the [m] field is regarded as the same value as the [M] field, and must not generate an error. This is because there is a possibility that the value of the [M] field in the ACCEPT message may be decreased by negotiation.
在受控负载服务的原始定义中，[m]字段的值必须小于或等于[m]字段的值。但是，在受控负载服务的ST FlowSpec中，如果[m]字段的值大于[m]字段的值，则[m]字段的值被视为与[m]字段相同的值，并且不得产生错误。这是因为接受消息中[M]字段的值可能会通过协商而减小。
In the ST2+ SCMP messages, the value of the [M] field must be equal to or less than 65,535. In the ACCEPT message that responds to CONNECT, or the NOTIFY message that contains the FlowSpec field, the value of the [M] field must be equal to the MaxMsgSize field in the message. If these values are not the same, FlowSpec is regarded as an error.
在ST2+SCMP消息中，[M]字段的值必须等于或小于65535。在响应CONNECT的ACCEPT消息或包含FlowSpec字段的NOTIFY消息中，[M]字段的值必须等于消息中的MaxMsgSize字段。如果这些值不相同，则将FlowSpec视为错误。
If the ST2+ agent receives the CONNECT message that contains unacceptable FlowSpec, the agent must generate a REFUSE message.
如果ST2+代理收到包含不可接受的FlowSpec的CONNECT消息，则该代理必须生成拒绝消息。
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not support Guaranteed Services. It will be supported by the UNI 3.1/4.0 version.
注：ATM上ST2+协议的UNI 3.1版本不支持保证服务。UNI 3.1/4.0版本将支持它。
The ST2+ over ATM protocol specifies an additional common SCMP element that designates the VC type used to support the diverse VC styles. The CONNECT and CHANGE messages that establish a hop with a VC must contain a VC-type common SCMP element. This element is valid between neighboring ST2+ agents, but must not propagate beyond the previous-hop or next-hop ST2+ agent.
ST2+over ATM协议指定了一个额外的通用SCMP元素，该元素指定用于支持各种VC样式的VC类型。与VC建立跃点的CONNECT和CHANGE消息必须包含VC类型的common SCMP元素。此元素在相邻ST2+代理之间有效，但不能传播到上一跳或下一跳ST2+代理之外。
The format of the VC-type common SCMP element is shown in Fig. 3.2.
VC型通用SCMP元素的格式如图3.2所示。
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PCode = 8 | PBytes = 20 | VCType |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PVCIdentifer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0(unused) | UniqueID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OriginIPAddress |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LIJCallIdentifer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PCode = 8 | PBytes = 20 | VCType |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PVCIdentifer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0(unused) | UniqueID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OriginIPAddress |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LIJCallIdentifer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Fig. 3.2: Format of VC-type common SCMP element.
图3.2:VC型通用SCMP元素格式。
The PCode field identifies the common SCMP elements. The PCode value for the VC type is 8.
PCode字段标识公共SCMP元素。VC类型的PCode值为8。
The PBytes field for the VC type is 20 bytes.
VC类型的PBytes字段为20字节。
The VCType field identifies the VC type. The correspondence between the value in this field and the meaning is as follows:
VCType字段标识VC类型。该字段中的值与含义的对应关系如下：
0: ST2+ data stream uses a PVC.
0:ST2+数据流使用PVC。
1: ST2+ data stream uses the reverse channel of the bi-directional point-to-point SVC used by the existing stream.
1:ST2+数据流使用现有流使用的双向点到点SVC的反向信道。
2: ST2+ data stream is established by a point-to-point SVC initiated from the upstream side.
2:ST2+数据流由从上游侧启动的点对点SVC建立。
3: ST2+ data stream is established by a point-to-multipoint SVC initiated from the upstream side.
3:ST2+数据流由从上游侧启动的点对多点SVC建立。
4: ST2+ data stream is established by a point-to-point SVC initiated from the downstream side.
4:ST2+数据流由从下游侧启动的点对点SVC建立。
5: ST2+ data stream is established by a point-to-multipoint SVC initiated from the downstream side.
5:ST2+数据流由从下游侧启动的点对多点SVC建立。
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not support VCType 5. It will be supported by the UNI 3.1/4.0 version.
注：ATM上ST2+协议的UNI 3.1版本不支持VCType 5。UNI 3.1/4.0版本将支持它。
The PVCIdentifer field identifies the PVC identifier uniquely assigned between neighboring ST2+ agents. This field is valid only when the VCType field is zero.
PVCIdentifer字段标识在相邻ST2+代理之间唯一分配的PVC标识符。仅当VCType字段为零时，此字段才有效。
The UniqueID and OriginIPAddress fields identify the reverse channel of the bi-directional point-to-point SVC that is used by this SID. These fields are valid only when the VCType field is 1.
UniqueID和OriginIPAddress字段标识此SID使用的双向点到点SVC的反向通道。仅当VCType字段为1时，这些字段才有效。
The LIJCallIdentifer field identifies the LIJ Call Identifier for point-to-multipoint SVC. This field is valid only when the VCType field is 5.
LIJCallIdentifier字段标识点对多点SVC的LIJ调用标识符。仅当VCType字段为5时，此字段才有效。
The extension of the Reason Code (RFC 1819, Section 10.5.3) to the ST2+ over ATM protocol is shown below.
将原因码（RFC 1819，第10.5.3节）扩展到ATM上的ST2+协议如下所示。
57 CantChange Partial changes not supported. 58 NoRecover Stream recovery not supported.
57不支持更改部分更改。58不支持NoRecover流恢复。
In the following case, the ST2+ over ATM protocol supports stream FlowSpec changes by using the CHANGE message.
在以下情况下，ST2+over ATM协议通过使用更改消息支持流流流规范更改。
o The I-bit is set to 1 and the G-bit is set to 1.
o I位设置为1，G位设置为1。
In the following case, the CHANGE fails and a REFUSE message, with the E and N-bits set to 1 and the ReasonCode set to CantChange, is propagated upstream.
在以下情况下，更改失败，拒绝消息（E和N位设置为1，ReasonCode设置为CantChange）向上游传播。
o The I and/or G-bits are set to zero.
o I和/或G位设置为零。
The ST2+ over ATM protocol does not support the ST2+ FlowSpec (RFC 1819, Section 9.2). The ST2+ FlowSpec specifies useful services, but requires the datalink layer to support heterogeneous QoS to receivers. The current ATM standard does not support heterogeneous QoS to receivers.
ATM上的ST2+协议不支持ST2+流量规范（RFC 1819，第9.2节）。ST2+FlowSpec指定了有用的服务，但要求数据链路层支持对接收器的异构QoS。当前的ATM标准不支持对接收器的异构QoS。
The ST2+ over ATM protocol does not support stream preemption (RFC 1819, Section 6.3). This is because the Integrated Services FlowSpec does not support the concept of precedence.
ATM上的ST2+协议不支持流抢占（RFC 1819，第6.3节）。这是因为集成服务流程规范不支持优先级的概念。
Implementations may not support the HELLO message (RFC 1819, Section 10.4.7) and thus ST2+ agent failure detection using the HELLO message (RFC 1819, Section 6.1.2). This is because ATM has an adequate failure detection mechanism, and the HELLO message is not sufficient for detecting link failure in the ST2+ over ATM protocol, because the ST2+ data and the ST2+ SCMP are forwarded through another VC.
实现可能不支持HELLO消息（RFC 1819，第10.4.7节），因此使用HELLO消息（RFC 1819，第6.1.2节）进行ST2+代理故障检测。这是因为ATM有足够的故障检测机制，而HELLO消息不足以检测ST2+over ATM协议中的链路故障，因为ST2+数据和ST2+SCMP是通过另一个VC转发的。
Implementors must select the NoRecover option of the CONNECT message (RFC 1819, Section 4.4.1) with the S-bit set to 1. This is because the descriptions of the stream recovery process in RFC 1819 (Sections 5.3.2, 6.2, and 6.2.1) are unclear and incomplete. It is thus possible that if a link failure occurs and several ST2+ agents detect it simultaneously, the recovery process may encounter problems.
实施者必须选择S位设置为1的连接消息（RFC 1819，第4.4.1节）的NoRecover选项。这是因为RFC 1819（第5.3.2节、第6.2节和第6.2.1节）中对流回收过程的描述不清楚且不完整。因此，如果发生链路故障并且多个ST2+代理同时检测到它，则恢复过程可能会遇到问题。
The ST2+ over ATM protocol does not support stream recovery. If recovery is needed, the application should support it. A CONNECT message in which the NoRecover option is not selected will fail; a REFUSE message in which the N-bit is set to 1 and the ReaseonCode is set to NoRecover is then propagated upstream.
ATM上的ST2+协议不支持流恢复。如果需要恢复，应用程序应该支持它。未选择NoRecover选项的CONNECT消息将失败；一个拒绝消息，其中N位设置为1，ReaseonCode设置为NoRecover，然后向上游传播。
The ST2+ over ATM protocol does not support subnet resources sharing (RFC 1819, Section 7.1.4). This is because ATM does not support the concept of the MAC layer.
ATM上的ST2+协议不支持子网资源共享（RFC 1819，第7.1.4节）。这是因为ATM不支持MAC层的概念。
The ST2+ over ATM protocol does not support IP encapsulation of ST (RFC 1819, Section 8.7), because there is no need to implement IP encapsulation in this protocol.
ATM上的ST2+协议不支持ST的IP封装（RFC 1819，第8.7节），因为不需要在该协议中实现IP封装。
The ST2+ over ATM protocol does not support IP multicasting (RFC 1819, Section 8.8), because this protocol does not support IP encapsulation of ST.
ATM上的ST2+协议不支持IP多播（RFC 1819，第8.8节），因为该协议不支持ST的IP封装。
The ST2+ receiver-oriented stream creation procedure has some fatal problems: the value of the LnkReferecnce field in the CONNECT message that is a response to a JOIN message is not valid, ST2+ agent cannot update the LnkReference field in the JOIN-REJECT message, and ST2+ agent cannot deliver the JOIN-REJECT message to the target because the JOIN-REJECT message does not contain a TargetList field. To solve these problems, the ST2+ over ATM protocol modifies the ST2+ protocol processing rules.
面向ST2+接收器的流创建过程存在一些致命问题：CONNECT消息中作为对JOIN消息的响应的LnkReference字段的值无效，ST2+代理无法更新JOIN-REJECT消息中的LnkReference字段，而ST2+代理无法将加入拒绝消息传递给目标，因为加入拒绝消息不包含TargetList字段。为了解决这些问题，ATM上的ST2+协议修改了ST2+协议处理规则。
Modifications of the CONNECT, JOIN, and JOIN-REJECT message processing rules in the ST2+ over ATM protocol are described in the following.
下文描述了ST2+over ATM协议中连接、加入和加入-拒绝消息处理规则的修改。
o The target that creates a JOIN message assigns the same value as in the Reference field to the LnkReference field.
o 创建联接消息的目标将与引用字段中的值相同的值分配给LNKREFENCE字段。
o The agent that creates a CONNECT message as a response to a JOIN message assigns the same value as in the LnkReference field in the JOIN message to the LnkReference field. In other cases, the value of the LnkReference field in a CONNECT message is zero.
o 创建连接消息作为对联接消息的响应的代理将与联接消息中的LNKREFENCE字段中的值相同的值分配给LNKREFENCE字段。在其他情况下，CONNECT消息中LNKREFENCE字段的值为零。
o The agent that creates a JOIN-REJECT message assigns the same value as in the LnkReference field in the JOIN message to the LnkReference field.
o 创建加入拒绝消息的代理将与加入消息中的LNKREFENCE字段中的值相同的值分配给LNKREFENCE字段。
o An intermediate agent must not modify the value of the LnkReference field in the CONNECT, JOIN, or JOIN-REJECT message. Note that this rule differs from the LnkReference field processing rule in the ACCEPT and REFUSE messages.
o 中间代理不得修改CONNECT、JOIN或JOIN-REJECT消息中LNKREFENCE字段的值。请注意，此规则不同于接受和拒绝消息中的LNKREFENCE字段处理规则。
The modified JOIN-REJECT control message in the ST2+ over ATM protocol is shown in Fig. 3.3
图3.3显示了ST2+over ATM协议中修改后的加入-拒绝控制消息
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OpCode = 9 | 0 | TotalBytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reference | LnkReference |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SenderIPAddress |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Checksum | ReasonCode |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GeneratorIPAddress |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: TargetList :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OpCode = 9 | 0 | TotalBytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reference | LnkReference |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SenderIPAddress |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Checksum | ReasonCode |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GeneratorIPAddress |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: TargetList :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Fig. 3.3: JOIN-REJECT Control Message.
图3.3：加入-拒绝控制消息。
The TargetList is assigned the same TargetList in the JOIN message as the one that corresponds to the JOIN-REJECT message.
在加入消息中为目标列表分配与加入拒绝消息对应的目标列表相同的目标列表。
This section specifies the AAL5 PDU encapusulation for the ST2+ Data PDU.
本节规定了ST2+数据PDU的AAL5 PDU封装。
The ST2+ data layer entity on the user plane of the ST2+ over ATM protocol provides the following services to the upper layer.
ST2+over ATM协议用户平面上的ST2+数据层实体向上层提供以下服务。
o st2p_unitdata.req
o st2p_unitdata.req
o st2p_unitdata.ind
o st2p_unitdata.ind
The st2p_unitdata.req primitive sends a request for an ST2+ Data PDU transfer to the ST2+ data layer entity. The semantics of the primitive are as follows:
st2p_unitdata.req原语向ST2+数据层实体发送ST2+数据PDU传输请求。原语的语义如下所示：
st2p_unitdata.req ( pri, sid, data )
st2p_unitdata.req（优先级、sid、数据）
The pri parameter specifies priority of ST2+ Data PDU. The sid parameter specifies SID of ST2+ Data PDU. The data parameter specifies ST2+ data to be transferred.
pri参数指定ST2+数据PDU的优先级。sid参数指定ST2+数据PDU的sid。数据参数指定要传输的ST2+数据。
The st2p_unitdata.ind primitive indicates an ST2+ Data PDU delivery from the ST2+ data layer entity. The semantics of the primitive are as follows:
st2p_unitdata.ind原语表示从ST2+数据层实体发送的ST2+数据PDU。原语的语义如下所示：
st2p_unitdata.ind ( pri [optional], sid, data, status [optional] )
st2p_unitdata.ind（优先级[可选]、sid、数据、状态[可选]）
The pri parameter indicates priority of ST2+ Data PDU, if AAL5 is used for encapsulating the ST2+ Data PDU. The sid parameter indicates SID of ST2+ Data PDU. The data parameter indicates delivered ST2+ data. The status is an optional parameter that indicates whether the delivered ST2+ data is corrupt or not.
如果AAL5用于封装ST2+数据PDU，pri参数表示ST2+数据PDU的优先级。sid参数表示ST2+数据PDU的sid。数据参数表示已交付的ST2+数据。状态是一个可选参数，用于指示交付的ST2+数据是否损坏。
The requirements for the AAL5 layer on the ST2+ over ATM user plane are as follows:
ATM上ST2+用户平面上的AAL5层要求如下：
o The SSCS must be null.
o SSC必须为空。
o Implementations must use message-mode service.
o 实现必须使用消息模式服务。
Note: Selection of the corrupted SDU delivery option on the receiver side depends on the implementation, so the receiver may or may not be able to select this option.
注意：接收器端损坏SDU交付选项的选择取决于实现，因此接收器可能无法选择此选项。
The AAL5 layer entity on the ST2+ over ATM user plane provides the following services to the ST2+ data layer.
ST2+over ATM用户平面上的AAL5层实体向ST2+数据层提供以下服务。
o AAL5_UNITDATA.req
o AAL5_UNITDATA.req
o AAL5_UNITDATA.ind
o AAL5_UNITDATA.ind
The AAL5_UNITDATA.req primitive sends a request for an AAL5 data (AAL5 CPCS_SDU) transfer from the ST2+ data layer entity to the AAL5 layer entity. The semantics of the primitive are as follows:
AAL5_UNITDATA.req原语发送从ST2+数据层实体到AAL5层实体的AAL5数据（AAL5 CPCS_SDU）传输请求。原语的语义如下所示：
AAL5_UNITDATA.req ( DATA, CPCS_LP, CPCS_UU )
AAL5_UNITDATA.req（数据、CPCS_LP、CPCS_UU）
The DATA parameter specifies the AAL5 data to be transferred. The CPCS_LP parameter specifies the value of the CLP field in the ATM cell. The CPCS_UU parameter specifies the user-to-user data to be transferred.
数据参数指定要传输的AAL5数据。CPCS_LP参数指定ATM信元中CLP字段的值。CPCS_UU参数指定要传输的用户到用户数据。
The AAL5_UNITDATA.ind indicates an AAL5 data (AAL5 CPCS_SDU) delivery from the AAL5 layer entity to the ST2+ data layer entity. The semantics of the primitive are as follows:
AAL5_UNITDATA.ind表示从AAL5层实体到ST2+数据层实体的AAL5数据（AAL5 CPCS_SDU）传递。原语的语义如下所示：
AAL5_UNITDATA.ind ( DATA, CPCS_LP, CPCS_UU, STATUS [optional] )
AAL5_UNITDATA.ind（数据、CPCS_LP、CPCS_UU、状态[可选]）
The DATA parameter indicates the delivered AAL5 data. The CPCS_LP parameter indicates the value of the CLP field in the ATM cell. The CPCS_UU parameter indicates the delivered user-to-user data. The STATUS parameter indicates whether the delivered AAL5 data is corrupt or not. The STATUS parameter is an optional parameter, and valid only when the corrupted SDU delivery option is selected.
数据参数表示交付的AAL5数据。CPCS_LP参数表示ATM信元中CLP字段的值。CPCS_UU参数表示交付的用户对用户数据。STATUS参数指示传递的AAL5数据是否损坏。状态参数是可选参数，仅在选择损坏的SDU传递选项时有效。
The ST2+ Data PDU is directly assigned to the DATA parameter in AAL5_UNITDATA.req. That is, as shown in Fig. 4.1, the ST2+ Data PDU is mapped to the payload of AAL5 CPCS_PDU.
ST2+数据PDU直接分配给AAL5_UNITDATA.req中的数据参数。即，如图4.1所示，ST2+数据PDU映射到AAL5 CPCS_PDU的有效载荷。
+-------+---------------------------+
| ST | ST2+ data | ST2+
| header| | Data PDU
+-------+---------------------------+
: :
: :
+---------------------------------------+--------+
| CPCS_PDU |PAD|CPCS_PDU| AAL5
| payload | |trailer | CPCS_PDU
+---------------------------------------+--------+
+-------+---------------------------+
| ST | ST2+ data | ST2+
| header| | Data PDU
+-------+---------------------------+
: :
: :
+---------------------------------------+--------+
| CPCS_PDU |PAD|CPCS_PDU| AAL5
| payload | |trailer | CPCS_PDU
+---------------------------------------+--------+
Fig. 4.1: Mapping of ST2+ data to AAL5 CPCS_PDU payload.
图4.1:ST2+数据到AAL5 CPCS_PDU有效载荷的映射。
The value of CPCS_LP in AAL5_UNITDATA.req depends on the implementation: 1 (low priority) or zero (high priority) may be assigned permanently, or they may be assigned depending on the value of pri in st2_unitdata.req.
AAL5_UNITDATA.req中CPCS_LP的值取决于实现：1（低优先级）或0（高优先级）可以永久分配，也可以根据st2_UNITDATA.req中pri的值分配。
The value of the CPCS_UU indication field in AAL5_UNITDATA.req is set to zero.
AAL5_UNITDATA.req中CPCS_UU指示字段的值设置为零。
The DATA parameter in AL5_UNITDATA.ind is directly assigned to the ST2+ Data PDU. That is, the payload in AAL5 CPCS_PDU is mapped to the ST2+ Data PDU.
AL5_UNITDATA.ind中的数据参数直接分配给ST2+数据PDU。也就是说，AAL5 CPCS_PDU中的有效负载映射到ST2+数据PDU。
If the value of STATUS in AAL5_UNITDATA.ind is valid, it is assigned to the status in st2p_unitdata.ind.
如果AAL5_UNITDATA.ind中的状态值有效，则会将其分配给st2p_UNITDATA.ind中的状态。
The value of MTU is Maximum CPCS_SDU size.
MTU的值是最大CPCS\U SDU大小。
The management plane specifies the Null FlowSpec, the Controlled-Load Service FlowSpec, and the Guaranteed Service FlowSpec mapping rules for UNI 3.1 traffic management.
管理平面为UNI 3.1流量管理指定空流程规范、受控负载服务流程规范和保证服务流程规范映射规则。
The Null FlowSpec is mapped to the UBR (VBR with the Best Effort Indicator).
空FlowSpec映射到UBR（带尽力指示器的VBR）。
The value of the PCR (CLP=0+1) is shown in section 6.7.2.
PCR值（CLP=0+1）如第6.7.2节所示。
The Controlled-Load FlowSpec is mapped to the VBR whose PCR (CLP=0+1), SCR (CLP=0+1), and MBS (CLP=0+1) are specified.
受控负载流规范映射到指定了PCR（CLP=0+1）、SCR（CLP=0+1）和MBS（CLP=0+1）的VBR。
The value of the PCR (CLP=0+1) is shown in section 6.7.2.
PCR值（CLP=0+1）如第6.7.2节所示。
Let scr be the calculated value of the SCR (CLP=0+1). Based on the
value of the [r] field in the Controlled-Load FlowSpec, it is given
by:
scr = ([r] / 48) * S,
Let scr be the calculated value of the SCR (CLP=0+1). Based on the
value of the [r] field in the Controlled-Load FlowSpec, it is given
by:
scr = ([r] / 48) * S,
where S is the coefficient of segmentation, and in an implementation, it must be configurable to any value between 1.0 and 56.0. The recommended default value is 1.2. The value of the SCR (CLP=0+1) is a minimum integer equal to or more than the calculated value of the scr.
其中S是分段系数，在实现中，它必须可配置为1.0和56.0之间的任何值。建议的默认值为1.2。SCR值（CLP=0+1）是等于或大于SCR计算值的最小整数。
Let mbs be the calculated value of the MBS (CLP=0+1). Based on the
value of the [b] field in the Controlled-Load FlowSpec, it is given
by:
mbs = ([b] / 48) * S.
Let mbs be the calculated value of the MBS (CLP=0+1). Based on the
value of the [b] field in the Controlled-Load FlowSpec, it is given
by:
mbs = ([b] / 48) * S.
The value of the MBS (CLP=0+1) is a minimum integer equal to or more than the calculated value of the mbs.
MBS的值（CLP=0+1）是等于或大于MBS计算值的最小整数。
The values of the [p] and [m] fields in the Controlled-Load FlowSpec are ignored.
忽略受控负载流规范中[p]和[m]字段的值。
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not support Guaranteed Services. It will be supported by the UNI 3.1/4.0 version.
注：ATM上ST2+协议的UNI 3.1版本不支持保证服务。UNI 3.1/4.0版本将支持它。
This section specifies the rules for encapsulating the ST2+ SCMP PDU into the AAL5 PDU, the relationship between ST2+ SCMP and PVC management for ST2+ data, and the protocol interaction between ST2+ SCMP and UNI 3.1 signaling.
本节规定了将ST2+SCMP PDU封装到AAL5 PDU中的规则、ST2+SCMP与ST2+数据PVC管理之间的关系以及ST2+SCMP与UNI 3.1信令之间的协议交互。
This subsection describes AAL5 PDU encapsulation for the ST2+ SCMP PDU. ST2+ Data PDU compatible encapsulation, AAL5 encapsulation based on RFC 1483, and on the RFC 1483 extension are specified. Selection of which one to use depends on the implementation.
本小节描述ST2+SCMP PDU的AAL5 PDU封装。指定了ST2+数据PDU兼容封装、基于RFC 1483的AAL5封装和基于RFC 1483扩展的AAL5封装。选择使用哪一个取决于实现。
The ST2+ over ATM protocol does not cover a VC (SVC/PVC) that transfers ST2+ SCMP. VCs for IPv4 transfer may be used for ST2+ SCMP transfer, and implementations may provide particular VCs for ST2+ SCMP transfer. Selection of these VCs depends on the implementation.
ATM上的ST2+协议不包括传输ST2+SCMP的VC（SVC/PVC）。IPv4传输的VCs可用于ST2+SCMP传输，并且实施方案可为ST2+SCMP传输提供特定的VCs。这些VCs的选择取决于实施情况。
The ST2+ Data PDU compatible encapsulation is shown in Fig. 6.1: the ST2+ SCMP PDU is mapped to the payload of AAL5 CPCS_PDU. Implementors should note that this encapsulation is not applicable when the ST2+ SCMP PDU is multiplexed with other protocols.
ST2+数据PDU兼容封装如图6.1所示：ST2+SCMP PDU映射到AAL5 CPCS_PDU的有效负载。实现者应该注意，当ST2+SCMP PDU与其他协议多路复用时，这种封装不适用。
+-------+---------------------------+
| ST | ST2+ SCMP | ST2+
| header| | SCMP PDU
+-------+---------------------------+
: :
: :
+---------------------------------------+--------+
| CPCS_PDU |PAD|CPCS_PDU| AAL5
| payload | |trailer | CPCS_PDU
+---------------------------------------+--------+
+-------+---------------------------+
| ST | ST2+ SCMP | ST2+
| header| | SCMP PDU
+-------+---------------------------+
: :
: :
+---------------------------------------+--------+
| CPCS_PDU |PAD|CPCS_PDU| AAL5
| payload | |trailer | CPCS_PDU
+---------------------------------------+--------+
Fig. 6.1: ST2+ Data PDU conpatible encapsulation.
图6.1:ST2+数据PDU可兼容封装。
The RFC 1483 base encapsulation is shown in Fig. 6.2: the ST2+ SCMP PDU with the RFC 1483 LLC encapsulation for routed protocol format is mapped to the payload in AAL5 CPCS_PDU.
RFC 1483基本封装如图6.2所示：采用RFC 1483 LLC封装的路由协议格式的ST2+SCMP PDU映射到AAL5 CPCS_PDU中的有效负载。
+------+----------------+
| ST | ST2+ SCMP | ST2+
|header| | SCMP PDU
+------+----------------+
: :
+---+---+---+-----------------------+
|LLC|OUI|PID| Information | IEEE 802 SNAP
| | | | | ISO 8802-2 LLC
+---+---+---+-----------------------+
: :
+---------------------------------------+--------+
| CPCS_PDU |PAD|CPCS_PDU| AAL5
| payload | |trailer | CPCS_PDU
+---------------------------------------+--------+
+------+----------------+
| ST | ST2+ SCMP | ST2+
|header| | SCMP PDU
+------+----------------+
: :
+---+---+---+-----------------------+
|LLC|OUI|PID| Information | IEEE 802 SNAP
| | | | | ISO 8802-2 LLC
+---+---+---+-----------------------+
: :
+---------------------------------------+--------+
| CPCS_PDU |PAD|CPCS_PDU| AAL5
| payload | |trailer | CPCS_PDU
+---------------------------------------+--------+
Fig. 6.2: RFC 1483 base encapsulation.
图6.2:RFC 1483基座封装。
The value of the LLC is 0xAA-AA-03, the value of the OUI is 0x00-00- 00, and the value of the PID is 0x08-00. The classification of the IPv4 and the ST2+ SCMP is determined by the IP version number, which is located in the first four bits of the IPv4 or ST headers.
LLC的值为0xAA-AA-03，OUI的值为0x00-00-00，PID的值为0x08-00。IPv4和ST2+SCMP的分类由IP版本号决定，该版本号位于IPv4或ST头的前四位。
The RFC 1483 extension base encapsulation is the same as for RFC 1483 base encapsulation, except that the value of the OUI is 0x00-00-5E (IANA) and the value of the PID is 0xXX-XX (TBD).
RFC 1483扩展基本封装与RFC 1483基本封装相同，只是OUI的值为0x00-00-5E（IANA），PID的值为0xXX XX（待定）。
The RFC 1483 base encapsulation for the SCMP is ideal, but requires modifying the IPv4 processing in the driver software of the WS or PC. Therefore, the RFC 1483 base encapsulation may be difficult to implement. This encapsulation is designed to solve this problem.
SCMP的RFC 1483基本封装是理想的，但需要在WS或PC的驱动程序软件中修改IPv4处理。因此，RFC 1483基本封装可能难以实现。此封装旨在解决此问题。
RFC 1819 ST2+ does not specify SCMP state machines. And the ST2+ over ATM protocol does not correspond to SCMP state machines. Therefore, the control plane specification assumes the following.
RFC 1819 ST2+未指定SCMP状态机。ATM上的ST2+协议与SCMP状态机不对应。因此，控制平面规范假设如下。
o The ST2+ agent has ST2+ SCMP layer entities that correspond to the next hops and the previous hop in the stream.
o ST2+代理具有与流中的下一个跃点和上一个跃点相对应的ST2+SCMP层实体。
o The SCMP layer entity terminates ACK, ERROR, and timeout processing and provides reliable SCMP delivery.
o SCMP层实体终止ACK、错误和超时处理，并提供可靠的SCMP传递。
o The origin consists of an upper layer entity, ST2+ SCMP layer entities for next hops, and a routing machine that delivers SCMP messages between these entities.
o 原点由上层实体、下一跳的ST2+SCMP层实体和在这些实体之间传递SCMP消息的路由机器组成。
o The intermediate agent consists of ST2+ SCMP layer entities for a previous hop and for next hops and a routing machine that delivers SCMP messages between these entities.
o 中间代理由上一跳和下一跳的ST2+SCMP层实体以及在这些实体之间传递SCMP消息的路由机器组成。
o The target consists of an upper layer entity, an ST2+ SCMP layer entity for a previous hop, and a routing machine that delivers SCMP messages between these entities.
o 目标由上层实体、前一跳的ST2+SCMP层实体和在这些实体之间传递SCMP消息的路由机器组成。
At least, the ST2+ SCMP layer entity for the next hop provides the following services to the routing machine.
至少，下一跳的ST2+SCMP层实体向路由机器提供以下服务。
o connect.req This primitive sends a request for a CONNECT message transfer to the ST2+ SCMP layer entity.
o connect.req此原语向ST2+SCMP层实体发送连接消息传输请求。
o change.req This primitive sends a request for a CHANGE message transfer to the ST2+ SCMP layer entity.
o change.req此原语向ST2+SCMP层实体发送更改消息传输请求。
o accept.ind This primitive indicates an ACCEPT message delivery from the ST2+ SCMP layer entity.
o accept.ind此原语表示接受来自ST2+SCMP层实体的消息传递。
o disconnect.req This primitive sends a request for a DISCONNECT message transfer to the ST2+ SCMP layer entity.
o disconnect.req此原语向ST2+SCMP层实体发送断开消息传输请求。
o refuse.ind This primitive indicates a REFUSE message delivery from the ST2+ SCMP layer entity, or indicates detection of an abnormal status such as an illegal message or timeout in the ST2+ SCMP layer entity.
o 拒绝.ind此原语表示拒绝来自ST2+SCMP层实体的消息传递，或表示检测到异常状态，如ST2+SCMP层实体中的非法消息或超时。
At least, the ST2+ SCMP layer entity for the previous hop provides the following services to the routing machine.
至少，前一跳的ST2+SCMP层实体向路由机器提供以下服务。
o connect.ind This primitive indicates a CONNECT message delivery from the ST2+ SCMP layer entity.
o connect.ind此原语表示从ST2+SCMP层实体传递的connect消息。
o change.ind This primitive indicates a CHANGE message delivery from the ST2+ SCMP layer entity.
o change.ind此原语表示来自ST2+SCMP层实体的更改消息传递。
o accept.req This primitive sends a request for an ACCEPT message transfer to the ST2+ SCMP layer entity.
o accept.req此原语向ST2+SCMP层实体发送接受消息传输请求。
o disconnect.ind This primitive indicates a DISCONNECT message delivery from the ST2+ SCMP layer entity, or indicates detection of an abnormal status such as an illegal message or timeout in the ST2+ SCMP layer entity.
o disconnect.ind此原语表示从ST2+SCMP层实体断开消息传递，或表示检测到异常状态，如ST2+SCMP层实体中的非法消息或超时。
o refuse.req This primitive sends a request for a REFUSE message transfer to the ST2+ SCMP layer entity.
o req该原语向ST2+SCMP层实体发送拒绝消息传输请求。
The UNI 3.1 signaling layer entity on the ST2+ over ATM control plane provides the following services to the ST2+ SCMP layer entity. The ST2+ over ATM protocol does not specify the UNI 3.1 signaling state
ST2+over ATM控制平面上的UNI 3.1信令层实体向ST2+SCMP层实体提供以下服务。ATM上的ST2+协议未指定UNI 3.1信令状态
machines. These are defined in [10, 12, 13].
机器。这些在[10,12,13]中有定义。
o setup.req This primitive sends a request for a SETUP message transfer from the ST2+ SCMP layer entity to the UNI 3.1 signaling layer entity. The ST2+ SCMP layer entity that sent this primitive receives an acknowledgment. If the setup succeeds the acknowledgment is a setup.conf primitive and if the setup fails it is a release.ind or release.conf primitive.
o setup.req此原语将设置消息传输请求从ST2+SCMP层实体发送到UNI 3.1信令层实体。发送此原语的ST2+SCMP层实体接收确认。如果安装成功，则确认为setup.conf原语，如果安装失败，则确认为release.ind或release.conf原语。
o setup.conf This primitive indicates a CONNECT message delivery from the UNI 3.1 signaling layer entity to the ST2+ SCMP layer entity.
o setup.conf此原语表示从UNI 3.1信令层实体到ST2+SCMP层实体的连接消息传递。
o setup.ind This primitive indicates a SETUP message delivery from the UNI 3.1 signaling layer entity to the ST2+ SCMP layer entity. The ST2+ SCMP layer entity that received this primitive sends an acknowledgment. If the setup is accepted the acknowledgment is a setup.resp primitive and if the setup is rejected it is a release.resp primitive if the state of the UNI 3.1 signaling layer entity is U6; otherwise it is a release.req primitive.
o setup.ind此原语表示从UNI 3.1信令层实体到ST2+SCMP层实体的设置消息传递。接收此原语的ST2+SCMP层实体发送确认。如果接受设置，则确认为setup.resp原语；如果拒绝设置，则确认为release.resp原语（如果UNI 3.1信令层实体的状态为U6）；否则它是一个release.req原语。
o setup.resp This primitive sends a request for a CONNECT message transfer from the ST2+ SCMP layer entity to the UNI 3.1 signaling layer entity. The ST2+ SCMP layer entity that sent this primitive receives an acknowledgment. If the setup is completed the acknowledgment is a setup-complete.ind primitive and if the setup fails it is a release.ind or release.conf primitive.
o setup.resp此原语将连接消息传输请求从ST2+SCMP层实体发送到UNI 3.1信令层实体。发送此原语的ST2+SCMP层实体接收确认。如果安装完成，则确认为setup-complete.ind原语，如果安装失败，则确认为release.ind或release.conf原语。
o setup-complete.ind This primitive indicates a CONNECT ACKNOWLEDGE message delivery from the UNI 3.1 signaling layer entity to the ST2+ SCMP layer entity.
o setup-complete.ind此原语表示从UNI 3.1信令层实体到ST2+SCMP层实体的连接确认消息传递。
o release.req This primitive sends a request for a RELEASE message transfer from the ST2+ SCMP layer entity to the UNI 3.1 signaling layer entity. The ST2+ SCMP layer entity that sent this primitive receives an acknowledgment that is a release.conf primitive.
o release.req此原语将释放消息传输请求从ST2+SCMP层实体发送到UNI 3.1信令层实体。发送此原语的ST2+SCMP层实体接收一个确认，该确认是release.conf原语。
o release.conf This primitive indicates a RELEASE COMPLETE message delivery, or indicates a RELEASE message delivery when the status of the UNI 3.1 signaling layer entity is U11, or indicates detection of an abnormal status such as an illegal message or timeout in the UNI 3.1 signaling layer entity, from the UNI 3.1 signaling layer entity
o release.conf此原语表示释放完成消息传递，或在UNI 3.1信令层实体的状态为U11时表示释放消息传递，或表示从UNI 3.1信令层实体检测到异常状态，如UNI 3.1信令层实体中的非法消息或超时
to the ST2+ SCMP layer entity.
到ST2+SCMP层实体。
o release.ind This primitive indicates a RELEASE message delivery from the UNI 3.1 signaling layer entity to the ST2+ SCMP layer entity when the status of the UNI 3.1 signaling layer entity is other than U11. The ST2+ SCMP layer entity that received this primitive sends an acknowledgment that is a release.resp primitive. And this primitive also indicates detection of an abnormal status such as an illegal message or timeout in the UNI 3.1 signaling layer entity and then a REFUSE message is transferred. In this case, the ST2+ SCMP layer entity that received this primitive receives a release.conf primitive in succession.
o release.ind此原语表示当UNI 3.1信令层实体的状态不是U11时，从UNI 3.1信令层实体到ST2+SCMP层实体的释放消息传递。接收此原语的ST2+SCMP层实体发送一个确认，该确认是release.resp原语。该原语还指示检测到异常状态，例如UNI 3.1信令层实体中的非法消息或超时，然后传输拒绝消息。在本例中，接收此原语的ST2+SCMP层实体将依次接收release.conf原语。
o release.resp This primitive sends a request for a RELEASE COMPLETE message transfer from the ST2+ SCMP layer entity to the UNI 3.1 signaling layer entity.
o release.resp此原语将释放完成消息传输请求从ST2+SCMP层实体发送到UNI 3.1信令层实体。
o add-party.req This primitive sends a request for an ADD PARTY message transfer from the ST2+ SCMP layer entity to the UNI 3.1 signaling layer entity. The ST2+ SCMP layer entity that sent this primitive receives an acknowledgment. If the setup is succeeds the acknowledgment is an add-party.conf primitive and if the setup fails it is a drop-party.conf primitive.
o add-party.req此原语将添加方消息传输请求从ST2+SCMP层实体发送到UNI 3.1信令层实体。发送此原语的ST2+SCMP层实体接收确认。如果安装成功，则确认为add-party.conf原语，如果安装失败，则确认为drop-party.conf原语。
o add-party.conf This primitive indicates an ADD PARTY ACKNOWLEDGE message delivery from the UNI 3.1 signaling layer entity to the ST2+ SCMP layer entity.
o add-party.conf此原语表示从UNI 3.1信令层实体到ST2+SCMP层实体的添加方确认消息传递。
o drop-party.req This primitive sends a request for a DROP PARTY message transfer from the ST2+ SCMP layer entity to the UNI 3.1 signaling layer entity. The ST2+ SCMP layer entity that sent this primitive receives an acknowledgment that is a drop-party.conf primitive.
o drop-party.req此原语将请求从ST2+SCMP层实体发送到UNI 3.1信令层实体的drop-party消息传输。发送此原语的ST2+SCMP层实体接收一个确认，该确认是drop-party.conf原语。
o drop-party.conf This primitive indicates an ADD PARTY REJECT message delivery, or indicates a DROP PARTY ACKNOWLEDGE message delivery, or indicates detection of an abnormal status such as an illegal message or timeout in the UNI 3.1 signaling layer entity, from the UNI 3.1 signaling layer entity to the ST2+ SCMP layer entity.
o drop-party.conf此原语表示添加方拒绝消息传递，或表示丢弃方确认消息传递，或表示检测到异常状态，如UNI 3.1信令层实体到ST2+SCMP层实体的UNI 3.1信令层实体中的非法消息或超时。
o drop-party.ind This primitive indicates a DROP PARTY message delivery from the UNI 3.1 signaling layer entity to the ST2+ SCMP layer entity. The ST2+
o drop-party.ind此原语表示从UNI 3.1信令层实体到ST2+SCMP层实体的丢弃方消息传递。ST2+
SCMP layer entity that sent this primitive receives an acknowledgment that is a drop-party.resp primitive.
发送此原语的SCMP层实体将接收一个作为drop-party.resp原语的确认。
o drop-party.resp This primitive sends a request for a DROP PARTY ACKNOWLEDGE message transfer from the ST2+ SCMP layer entity to the UNI 3.1 signaling layer entity.
o drop-party.resp此原语发送请求，请求从ST2+SCMP层实体向UNI 3.1信令层实体传输drop-party确认消息。
The ST2+ over ATM protocol supports PVC, the reverse channel of bi-directional SVC, point-to-point SVC, and point-to-multipoint SVC for ST2+ Data PDU transfer. And SVC supports both upstream and downstream call initiation styles.
ST2+over ATM协议支持PVC，即双向SVC、点对点SVC和点对多点SVC的反向信道，用于ST2+数据PDU传输。SVC同时支持上游和下游调用启动样式。
A 32-bit PVC identifier that is unique between neighboring ST2+ agents is assigned to each PVC. And the reverse channel of the bi-directional point-to-point SVC used by the existing stream is identified by the SID of the stream that occupies the forward channel.
为每个PVC分配一个在相邻ST2+代理之间唯一的32位PVC标识符。并且现有流使用的双向点到点SVC的反向信道由占用前向信道的流的SID标识。
When the ST2+ agent sets up a stream or changes QoS, the ST2+ agent must select one VC style from these SVC and PVC styles as a hop that is part of the stream. In the ST2+ over ATM protocol, VC style selection criteria depend on the implementation.
当ST2+代理设置流或更改QoS时，ST2+代理必须从这些SVC和PVC样式中选择一种VC样式作为流的一部分的跃点。在ST2+over ATM协议中，VC风格的选择标准取决于实现。
This subsection describes examples of VC style selection criteria for the ST2+ over ATM protocol as a reference for implementors. Note that the following descriptions in this subsection are not part of the ST2+ over ATM protocol specification.
本小节描述了ST2+over ATM协议的VC风格选择标准示例，供实施者参考。请注意，本小节中的以下描述不是ST2+over ATM协议规范的一部分。
At least, the ST2+ agent may have to manage the following information for each PVC that can be used by ST2+ Data PDU transfer.
至少，ST2+代理可能必须管理ST2+数据PDU传输可使用的每个PVC的以下信息。
o PVC identifier
o PVC标识符
o ATM interface identifier in the ST2+ agent
o ST2+代理中的ATM接口标识符
o VPI/VCI
o VPI/VCI
o State of VC: e.g. enabled or disabled, occupied or vacant
o VC状态：例如启用或禁用、占用或空闲
o QoS of VC
o VC的QoS
o Nexthop IP address
o 下一个IP地址
When a PVC is selected for a hop of a stream, at least confirmations, that is the state of the PVC is vacant and the next hop IP address and QoS are consistent with the requirements from the stream, may be needed.
当为流的跳选择PVC时，可能需要至少确认，即PVC的状态为空，并且下一跳IP地址和QoS与来自流的要求一致。
It is also feasible to introduce access lists to each PVC and to consider the access lists in the selection process. Examples of an access list are shown in the following.
将访问列表引入每个PVC并考虑选择过程中的访问列表也是可行的。访问列表的示例如下所示。
o Permit or deny use by a stream whose the previous hop is specified.
o 允许或拒绝指定前一跳的流使用。
o Permit or deny use by a stream whose the origin is specified.
o 允许或拒绝指定来源的流使用。
o Permit or deny use by a stream whose the SID is specified.
o 允许或拒绝指定SID的流使用。
o Permit or deny use by a stream whose the target is specified.
o 允许或拒绝指定目标的流使用。
o Permit or deny use by a stream whose the target and SAP are specified.
o 允许或拒绝指定了目标和SAP的流使用。
o Any combination of the above.
o 上述各项的任意组合。
6.4.2 Examples of reverse channel of bi-directional SVC selection criteria
6.4.2 双向SVC选择标准的反向通道示例
At least, the ST2+ agent may have to manage the following information for each reverse channel of bi-directional SVCs.
至少，ST2+代理可能必须为双向SVC的每个反向信道管理以下信息。
o SID of the stream that occupies the forward channel
o 占用前向通道的流的SID
o ATM interface identifier in the ST2+ agent
o ST2+代理中的ATM接口标识符
o VPI/VCI
o VPI/VCI
o State of the reverse channel in the VC: e.g. enabled or disabled, occupied or vacant
o VC中反向通道的状态：例如启用或禁用、占用或空闲
o QoS of VC
o VC的QoS
o Nexthop IP address
o 下一个IP地址
When a reverse channel of the bi-directional point-to-point SVC used by the existing stream is selected for a hop of a stream, at least confirmations, that is the state of the channel is vacant and the next hop IP address and QoS are consistent with the requirements from the stream, may be needed.
当为流的跳选择由现有流使用的双向点到点SVC的反向信道时，可能需要至少确认，即信道的状态为空并且下一跳IP地址和QoS与来自流的要求一致。
It is also feasible to introduce selection rules to the ST2+ agent. Examples of selection rule are shown in the following.
将选择规则引入ST2+代理也是可行的。选择规则的示例如下所示。
o Permit reuse of the reverse channel by a stream whose the origin is one of targets in the stream that occupies the forward channel.
o 允许源是占用前向信道的流中的目标之一的流重用反向信道。
o Permit reuse of the reverse channel by a stream whose one of targets is the origin in the stream that occupies the forward channel.
o 允许目标之一是占用正向信道的流中的源的流重用反向信道。
o Permit reuse of the reverse channel by a stream whose the previous hop is one of the next hops in the stream that occupies the forward channel.
o 允许前一跳是占用前向信道的流中的下一跳之一的流重用反向信道。
o Any combination of the avobe.
o avobe的任何组合。
When an SVC is used for a hop of a stream, at first, the ST2+ agent must select point-to-point or point-to-multipoint SVC. Examples of this selection rule are shown in the following.
当SVC用于流的一个跃点时，首先，ST2+代理必须选择点对点或点对多点SVC。此选择规则的示例如下所示。
o If the network supports only point-to-point SVC, select it.
o 如果网络仅支持点对点SVC，请选择它。
o If the network supports point-to-multipoint SVC, select it.
o 如果网络支持点对多点SVC，请选择它。
If point-to-point SVC is selected, the ST2+ agent must select upstream or downstream call initiation style. Examples of this selection rule are shown in the following.
如果选择了点对点SVC，则ST2+代理必须选择上游或下游呼叫发起样式。此选择规则的示例如下所示。
o A VC for a stream whose previous hop is specified is initiated from upstream or downstream.
o 指定了前一跳的流的VC从上游或下游启动。
o A VC for a stream whose next hop is specified is initiated from upstream or downstream.
o 指定下一跳的流的VC从上游或下游启动。
o A VC for a stream whose origin is specified is initiated from upstream or downstream.
o 指定来源的流的VC从上游或下游启动。
o A VC for a stream whose SID is specified is initiated from upstream or downstream.
o 指定SID的流的VC从上游或下游启动。
o A VC for a stream whose target is specified is initiated from upstream or downstream.
o 指定目标的流的VC从上游或下游启动。
o A VC for a stream whose target and SAP are specified is initiated from upstream or downstream.
o 指定了目标和SAP的流的VC从上游或下游启动。
o Any combination of the above.
o 上述各项的任意组合。
This subsection specifies VC management in the ST2+ over ATM protocol.
本小节规定了ST2+over ATM协议中的VC管理。
When outgoing call processing of the first leaf of a point-to-multipoint SVC or a point-to-point SVC is required inside the ST2+ SCMP layer entity, a setup.req primitive is sent to the UNI 3.1 signaling layer entity. If the UNI 3.1 signaling layer entity responds with a setup.conf primitive, the call processing is assumed to have succeeded. If the UNI 3.1 signaling layer entity responds with anything other than this primitive, the processing rule is the same as the SVC disconnect processing that is shown in section 6.5.4 and the outgoing call processing is assumed to have failed.
当ST2+SCMP层实体内需要对点对多点SVC或点对点SVC的第一个叶进行传出呼叫处理时，setup.req原语被发送到UNI 3.1信令层实体。如果UNI 3.1信令层实体响应setup.conf原语，则假定呼叫处理已成功。如果UNI 3.1信令层实体响应的不是该原语，则处理规则与第6.5.4节所示的SVC断开连接处理相同，并假定传出呼叫处理失败。
When outgoing call processing of a later leaf of a point-to-multipoint SVC is required, an add-party.req primitive is sent to the UNI 3.1 signaling layer entity. If the UNI 3.1 signaling layer entity responds with an add-party.conf primitive, the call processing is assumed to have succeeded. If the UNI 3.1 signaling layer entity responds with anything other than this primitive, the processing rule is the same as the SVC disconnect processing that is shown in section 6.5.4 and the outgoing call processing is assumed to have failed.
当需要对点对多点SVC的后一个叶进行传出呼叫处理时，向UNI 3.1信令层实体发送add-party.req原语。如果UNI 3.1信令层实体响应add-party.conf原语，则假定呼叫处理已成功。如果UNI 3.1信令层实体响应的不是该原语，则处理规则与第6.5.4节所示的SVC断开连接处理相同，并假定传出呼叫处理失败。
When an incoming call processing of SVC is required inside the ST2+ SCMP layer entity, it sets a watchdog timer. The time interval of the timer depends on the implementation.
当ST2+SCMP层实体内需要SVC的传入呼叫处理时，它会设置看门狗定时器。计时器的时间间隔取决于实现。
The ST2+ SCMP layer entity waits for a setup.ind primitive indication from the UNI 3.1 signaling layer entity. When this primitive is indicated and the parameters in it are acceptable, the ST2+ SCMP layer entity responds with a setup.resp primitive. If the parameters are not acceptable, the ST2+ SCMP layer entity stops the timer, and if the state of the UNI 3.1 signaling layer entity is U6, the entity responds with a release.resp primitive, and if the state is other than this, the entity responds with a release.req primitive, and then waits for a release.conf primitive response and the incoming call processing is assumed to have failed.
ST2+SCMP层实体等待来自UNI 3.1信令层实体的setup.ind原语指示。当指示此原语且其中的参数可接受时，ST2+SCMP层实体将使用setup.resp原语进行响应。如果参数不可接受，则ST2+SCMP层实体停止计时器，如果UNI 3.1信令层实体的状态为U6，则该实体用release.resp原语响应，如果状态不是这样，则该实体用release.req原语响应，然后等待release.conf原语响应，并假定传入呼叫处理失败。
If the ST2+ SCMP layer entity responds with a setup.resp primitive, then the entity waits for the next primitive indication, and when the next primitive is indicated, the ST2+ SCMP layer entity stops the
如果ST2+SCMP层实体以setup.resp原语响应，则该实体将等待下一个原语指示，当指示下一个原语时，ST2+SCMP层实体将停止
timer. If a setup-complete.ind primitive is indicated, the incoming call processing is assumed to have succeeded. If the UNI 3.1 signaling layer entity responds with anything other than this primitive or if the timer expires, the processing rule is the same as the SVC disconnect processing that is shown in section 6.5.4 and the incoming call processing is assumed to have failed.
计时器。如果指示setup-complete.ind原语，则假定传入呼叫处理已成功。如果UNI 3.1信令层实体响应除此原语之外的任何内容，或者如果计时器过期，则处理规则与第6.5.4节所示的SVC断开连接处理相同，并且假设传入呼叫处理失败。
When a VC release is required inside an ST2+ SCMP layer entity, if the previous hop or next hop is connected with a PVC, the PVC state is set to vacant and the VC release processing is assumed to be completed.
当ST2+SCMP层实体内需要VC释放时，如果前一个跃点或下一个跃点与PVC连接，则PVC状态设置为空闲，并且假设VC释放处理已完成。
If the previous hop or next hop is connected with a point-to-point SVC whose reverse channel is occupied, the state of the channel in the VC is set to vacant, the SID information of the VC is updated, and the VC release processing is assumed to be completed.
如果上一跳或下一跳与反向信道被占用的点对点SVC连接，则VC中的信道状态被设置为空闲，VC的SID信息被更新，并且假设VC释放处理已完成。
If the previous hop or next hop is connected with a point-to-point SVC whose reverse channel is vacant, if the previous hop is connected with a point-to-multipoint SVC, or if the next hop is connected with a point-to-multipoint SVC and the number of leaves is 1, then the ST2+ SCMP layer entity sends a release.req primitive to the UNI 3.1 signaling layer entity, then waits for a release.conf primitive indication; when one is indicated, the VC release processing is assumed to be completed.
如果上一跳或下一跳与反向信道为空的点对点SVC连接，如果上一跳与点对多点SVC连接，或者如果下一跳与点对多点SVC连接且叶数为1，然后ST2+SCMP层实体向UNI 3.1信令层实体发送release.req原语，然后等待release.conf原语指示；当指示一个时，假设VC发布处理已完成。
If the next hop is connected with a point-to-multipoint SVC and the number of leaves is other than 1, the ST2+ SCMP layer entity sends a drop-party.req primitive to the UNI 3.1 signaling layer entity, then waits for a drop-party.conf primitive indication; when one is indicated, the VC release processing is assumed to be completed.
如果下一跳与点对多点SVC连接，且叶数不是1，则ST2+SCMP层实体向UNI 3.1信令层实体发送drop-party.req原语，然后等待drop-party.conf原语指示；当指示一个时，假设VC发布处理已完成。
If an ST2+ SCMP layer entity corresponds to a UNI 3.1 signaling layer entity, and if the ST2+ SCMP layer entity is sent a release.ind primitive from the UNI 3.1 signaling layer entity, whose cause is a delivery of a RELEASE message, the ST2+ SCMP layer entity responds with a release.resp primitive, and then the VC disconnect processing is assumed to be completed. If the ST2+ SCMP layer entity is sent a release.ind primitive, whose cause is other than the previous case, the ST2+ SCMP layer entity waits for a release.conf primitive response. When a release.conf primitive is indicated, the VC disconnect processing is assumed to be completed.
如果ST2+SCMP层实体对应于UNI 3.1信令层实体，并且如果ST2+SCMP层实体从UNI 3.1信令层实体发送了release.ind原语，其原因是释放消息的传递，则ST2+SCMP层实体用release.resp原语响应，然后假设VC断开连接处理已完成。如果向ST2+SCMP层实体发送了一个release.ind原语，其原因与前一种情况不同，则ST2+SCMP层实体将等待release.conf原语响应。当指示release.conf原语时，假设VC断开连接处理已完成。
Note that if next hops from ST2+ SCMP layer entities are connected with a point-to-multipoint SVC, the ST2+ SCMP layer entities to next hops correspond to a UNI 3.1 signaling layer entity. In this case, if the ST2+ SCMP layer entities are sent release.ind primitives from the UNI 3.1 signaling layer entity, whose cause is the delivery of a RELEASE message, one of the ST2+ SCMP layer entities responds with a release.resp primitive, and then the VC disconnect processing in the entities that are sent release.ind primitives are assumed to be completed. If the ST2+ SCMP layer entities are sent release.ind primitives, whose cause is other than the previous case, the ST2+ SCMP layer entities wait for release.conf primitives responses. When release.conf primitives are indicated, the VC disconnect processing in the entities that are indicated release.ind primitives are assumed to be completed.
注意，如果来自ST2+SCMP层实体的下一跳与点对多点SVC连接，则到下一跳的ST2+SCMP层实体对应于UNI 3.1信令层实体。在这种情况下，如果ST2+SCMP层实体从UNI 3.1信令层实体发送release.ind原语，其原因是释放消息的传递，则其中一个ST2+SCMP层实体用release.resp原语响应，然后，假定发送release.ind原语的实体中的VC断开连接处理已完成。如果发送ST2+SCMP层实体的是release.ind原语（其原因与前一种情况不同），则ST2+SCMP层实体将等待release.conf原语响应。当指示release.conf原语时，假定指示release.ind原语的实体中的VC断开连接处理已完成。
If the ST2+ SCMP layer entity is sent a drop-party.ind primitive from the UNI 3.1 signaling layer entity, the ST2+ SCMP layer entity responds with a drop-party.resp primitive, and then the VC disconnect processing is assumed to be completed. If the ST2+ SCMP layer entity is sent a drop-party.conf primitive, the VC disconnect processing is assumed to be completed.
如果ST2+SCMP层实体从UNI 3.1信令层实体发送一个drop-party.ind原语，则ST2+SCMP层实体用drop-party.resp原语响应，然后假设VC断开连接处理已完成。如果向ST2+SCMP层实体发送drop-party.conf原语，则假定VC断开连接处理已完成。
This subsection specifies the additional SCMP processing rules that are defined in RFC 1819 ST2+ protocol specification. The following additional rules are applied when the previous hop or next hop is connected with an ATM connection in the ST2+ SCMP layer entity.
本小节规定了RFC 1819 ST2+协议规范中定义的附加SCMP处理规则。当上一跳或下一跳与ST2+SCMP层实体中的ATM连接连接时，将应用以下附加规则。
When a connect.req primitive is sent to the ST2+ SCMP layer entity for the next hop, the entity confirms whether or not the VC for the next hop exists.
将connect.req原语发送到下一跳的ST2+SCMP层实体时，该实体确认下一跳的VC是否存在。
If it does, the entity forwards a CONNECT message that does not include a VC-type common SCMP element to the next hop.
如果是，则实体将不包含VC类型公共SCMP元素的CONNECT消息转发到下一个跃点。
If it does not, the entity selects a VC style. If the result is a PVC or a reverse channel of a bi-directional point-to-point SVC used by an existing stream, the VC state is set to occupied. The entity forwards a CONNECT message with a VC-type common SCMP element that reflects the result of the selection to the next hop.
如果没有，实体将选择VC样式。如果结果是现有流使用的双向点到点SVC的PVC或反向通道，则VC状态设置为已占用。实体使用VC类型的公共SCMP元素将CONNECT消息转发到下一个跃点，该元素反映选择的结果。
The ST2+ SCMP layer entity for the previous hop confirms whether or not the CONNECT message includes a VC-type common SCMP element.
前一跳的ST2+SCMP层实体确认连接消息是否包含VC类型的公共SCMP元素。
If a VC-type common SCMP element is not included and the VC for the next hop exists, a connect.ind primitive is sent to the routing machine. If the VC for the next hop does not exist, a REFUSE message is forwarded to the previous hop.
如果不包括VC类型的common SCMP元素，并且存在下一个跃点的VC，则会向路由计算机发送connect.ind原语。如果下一个跃点的VC不存在，将拒绝消息转发到上一个跃点。
If a VC-type common SCMP element is included and a point-to-point SVC, whose calling party is the upstream or downstream, or a point-to-multipoint SVC is specified, a connect.ind primitive is sent to the routing machine. If a PVC or a reverse channel of a bi-directional point-to-point SVC used by an existing stream is specified and the specified VC exists, the VC state is set to occupied and a connect.ind primitive is sent to the routing machine. Otherwise, a REFUSE message is forwarded to the previous hop.
如果包含VC类型的通用SCMP元素，并且指定了调用方为上游或下游的点对点SVC或点对多点SVC，则会向路由计算机发送connect.ind原语。如果指定了现有流使用的双向点到点SVC的PVC或反向通道，并且指定的VC存在，则VC状态设置为已占用，并向路由计算机发送connect.ind原语。否则，将拒绝消息转发到上一跳。
When a change.req primitive is sent to the ST2+ SCMP layer entity for the next hop, the entity releases the VC whose process is shown in section 6.5.3.
当change.req原语被发送到ST2+SCMP层实体进行下一跳时，该实体将释放VC，其过程如第6.5.3节所示。
Then, the entity selects a VC style. If the result is a PVC or a reverse channel of a bi-directional point-to-point SVC used by an existing stream, the VC state is set to occupied. The entity forwards a CHANGE message with a VC-type common SCMP element that reflects the result of the selection to the next hop.
然后，实体选择VC样式。如果结果是现有流使用的双向点到点SVC的PVC或反向通道，则VC状态设置为已占用。实体使用VC类型的公共SCMP元素将更改消息转发到下一个跃点，该元素反映选择的结果。
The ST2+ SCMP layer entity for the previous hop confirms whether the CHANGE message includes a VC-type common SCMP element. If a VC-type common SCMP element is not included, a REFUSE message is forwarded to the previous hop.
前一跳的ST2+SCMP层实体确认更改消息是否包含VC类型的公共SCMP元素。如果不包括VC类型的公共SCMP元素，则会将拒绝消息转发到上一个跃点。
If a VC-type common SCMP element is included, the entity releases the VC whose process is shown in section 6.5.3. If the element specifies a point-to-point SVC, whose calling party is the upstream or downstream, or a point-to-multipoint SVC, a change.ind primitive is sent to the routing machine. If a PVC or a reverse channel of a bi-directional point-to-point SVC used by an existing stream is specified and the specified VC exists, the VC state is set to occupied and a change.ind primitive is sent to the routing machine. Otherwise, a REFUSE message is forwarded to the previous hop.
如果包含VC类型的通用SCMP元素，实体将释放VC，其过程如第6.5.3节所示。如果元素指定了一个调用方为上游或下游的点对点SVC，或一个点对多点SVC，则会向路由计算机发送change.ind原语。如果指定了现有流使用的双向点对点SVC的PVC或反向通道，并且指定的VC存在，则VC状态设置为已占用，并向路由计算机发送change.ind原语。否则，将拒绝消息转发到上一跳。
When an accept.req primitive is sent to the ST2+ SCMP layer entity for the previous hop, the entity confirms the state of the UNI 3.1 signaling layer entity. If the state of the entity is other than U0
当向上一跳的ST2+SCMP层实体发送accept.req原语时，该实体确认UNI 3.1信令层实体的状态。如果实体的状态不是U0
or U10, the accept.req primitive is queued and is processed after the state changes to U0 or U10.
或者U10，accept.req原语排队，并在状态更改为U0或U10后处理。
If the state of the entity is U0 or U10, the ST2+ SCMP layer entity confirms whether or not the VC for the previous hop exists. If it does, an ACCEPT message is forwarded to the previous hop.
如果实体的状态为U0或U10，则ST2+SCMP层实体确认前一跳的VC是否存在。如果是，则接受消息将转发到上一个跃点。
If it does not and the CONNECT or CHANGE message that corresponds to the accept.req primitive specified a point-to-point SVC whose calling party is the upstream or a point-to-multipoint SVC, then the entity processes an incoming call that is shown in section 6.5.2. If the incoming call processing succeeds, an ACCEPT message is forwarded to the previous hop. If the CONNECT or CHANGE message that corresponds to the accept.req primitive specified a point-to-point SVC whose calling party is downstream, the entity converts from the IP address of the previous hop to the ATM address, and then the entity processes an outgoing call that is shown in section 6.5.1. If the outgoing call processing succeeds, an ACCEPT message is forwarded to the previous hop. For cases other than those described above or if the incoming or outgoing call processing fails, a REFUSE message is forwarded to the previous hop and a disconnect.ind primitive is sent to the routing machine.
如果没有，且对应于accept.req原语的CONNECT或CHANGE消息指定了主叫方为上游的点对点SVC或点对多点SVC，则实体处理第6.5.2节所示的传入呼叫。如果传入呼叫处理成功，接受消息将转发到上一跳。如果对应于accept.req原语的CONNECT或CHANGE消息指定了主叫方为下游的点对点SVC，则该实体将前一跳的IP地址转换为ATM地址，然后该实体处理第6.5.1节所示的传出呼叫。如果传出呼叫处理成功，则接受消息将转发到上一跳。对于上述情况以外的情况，或者如果传入或传出呼叫处理失败，将拒绝消息转发到上一个跃点，并将disconnect.ind原语发送到路由机器。
When an ACCEPT message is processed in the ST2+ SCMP layer entity for the next hop, the entity confirms the state of the UNI 3.1 signaling layer entity. If the state of the entity is other than U0 or U10, the ACCEPT message is queued and is processed after the state changes to U0 or U10.
当在ST2+SCMP层实体中为下一跳处理接受消息时，该实体确认UNI 3.1信令层实体的状态。如果实体的状态不是U0或U10，则接受消息将排队，并在状态更改为U0或U10后进行处理。
If the state of the entity is U0 or U10, the ST2+ SCMP layer entity confirms whether or not the VC for the next hop exists. If it does, an accept.ind primitive is sent to the routing machine.
如果实体的状态为U0或U10，则ST2+SCMP层实体确认下一跳的VC是否存在。如果是，则会向路由计算机发送accept.ind原语。
If it does not and the CONNECT or CHANGE message that corresponds to the ACCEPT message specified a point-to-point SVC whose calling party is the upstream or a point-to-multipoint SVC, then the entity converts from the IP address of the next hop to the ATM address, and then the entity processes an outgoing call that is shown in section 6.5.1. If the outgoing call processing succeeds, an accept.ind primitive is sent to the routing machine. If the CONNECT or CHANGE message that corresponds to the ACCEPT message specified a point-to-point SVC whose calling party is downstream, the entity processes an incoming call that is shown in section 6.5.2. If the incoming call processing succeeds, an accept.ind primitive is sent to the routing machine. For cases other than those described above or if the incoming or outgoing call processing fails, a refuse.ind primitive is
如果没有，且对应于接收消息的CONNECT或CHANGE消息指定为主叫方为上游的点对点SVC或点对多点SVC，则实体将从下一跳的IP地址转换为ATM地址，然后实体处理第6.5.1节所示的传出呼叫。如果传出呼叫处理成功，则会向路由计算机发送accept.ind原语。如果与接受消息相对应的CONNECT或CHANGE消息由主叫方位于下游的点对点SVC指定，则实体将处理第6.5.2节所示的传入呼叫。如果传入呼叫处理成功，则会向路由计算机发送accept.ind原语。对于上述情况以外的情况，或者如果传入或传出呼叫处理失败，则使用拒绝.ind原语
sent to the routing machine and a DISCONNECT message is forwarded to the next hop.
发送到路由机器，断开连接消息转发到下一个跃点。
At first, the ST2+ SCMP layer entity for the next hop forwards a DISCONNECT message to the next hop.
首先，下一跳的ST2+SCMP层实体将断开连接消息转发给下一跳。
And then, after the disconnect.req processing, if there are no more targets that are connected downstream of the entity and the entity is not waiting for an ACCEPT or REFUSE message response from targets, the entity releases the VC whose process is shown in section 6.5.3.
然后，在disconnect.req处理之后，如果没有更多的目标连接到实体的下游，并且实体没有等待来自目标的接受或拒绝消息响应，则实体释放VC，其过程如第6.5.3节所示。
AT first, after the disconnect.ind processing, if there are no more targets that are connected downstream of the ST2+ SCMP layer entity for the previous hop and the entity is not waiting for an ACCEPT or REFUSE message response from targets, the entity releases the VC whose process is shown in section 6.5.3.
首先，在disconnect.ind处理之后，如果没有更多的目标连接到上一跳的ST2+SCMP层实体的下游，并且该实体没有等待来自目标的接受或拒绝消息响应，则该实体释放VC，其过程如第6.5.3节所示。
And then, the entity sends a disconnect.ind primitive to the routing machine.
然后，实体向路由机器发送disconnect.ind原语。
At first, the ST2+ SCMP layer entity for the previous hop forwards a REFUSE message to the previous hop.
首先，前一跳的ST2+SCMP层实体将拒绝消息转发给前一跳。
And then, after the refuse.req processing, if there are no more targets that are connected downstream of the entity and the entity is not waiting for an ACCEPT or REFUSE message response from targets, the entity releases the VC whose process is shown in section 6.5.3.
然后，在拒绝.req处理之后，如果没有更多的目标连接到实体的下游，并且实体没有等待来自目标的接受或拒绝消息响应，则实体释放VC，其过程如第6.5.3节所示。
At first, after the refuse.ind processing, if there are no more targets that are connected downstream of the ST2+ SCMP layer entity for the next hop and the entity is not waiting for an ACCEPT or REFUSE message response from targets, the entity releases the VC whose process is shown in section 6.5.3.
首先，在拒绝.ind处理之后，如果没有更多的目标连接到ST2+SCMP层实体的下游用于下一跳，并且该实体没有等待来自目标的接受或拒绝消息响应，则该实体释放VC，其过程如第6.5.3节所示。
And then, the entity sends a refuse.ind primitive to the routing machine.
然后，实体向路由机器发送一个拒绝.ind原语。
When the ST2+ SCMP layer entity for the previous hop is sent a SVC disconnect processing from the UNI 3.1 signaling layer entity and then the SVC disconnect processing is completed, the entity forwards a REFUSE message to the previous hop and sends a disconnect.ind primitive to the routing machine.
当前一跳的ST2+SCMP层实体从UNI 3.1信令层实体发送一个SVC断开连接处理，然后SVC断开连接处理完成时，该实体将拒绝消息转发给前一跳，并向路由机器发送disconnect.ind原语。
When the ST2+ SCMP layer entity for the next hop is sent a SVC disconnect processing from the UNI 3.1 signaling layer entity and then the SVC disconnect processing is completed, the entity sends a refuse.ind primitive to the routing machine and forwards a DISCONNECT message to the previous hop.
当下一跳的ST2+SCMP层实体从UNI 3.1信令层实体发送一个SVC断开连接处理，然后SVC断开连接处理完成时，该实体向路由机器发送一个拒绝.ind原语，并将一个断开连接消息转发给前一跳。
The ST2+ over ATM protocol does not specify the coding rules needed for the following information elements in UNI 3.1 signaling. The usages of these information elements are specified in [10].
ATM上的ST2+协议未规定UNI 3.1信令中以下信息元素所需的编码规则。[10]中规定了这些信息元素的用法。
o Protocol discriminator
o 协议鉴别器
o Call reference
o 呼叫参考
o Message type
o 消息类型
o Message length
o 消息长度
o Call state
o 呼叫状态
o Called party number
o 被叫方号码
o Called party subaddress
o 被叫方子地址
o Calling party number
o 主叫方号码
o Calling party subaddress
o 主叫方子地址
o Cause
o 原因
o Connection identifier
o 连接标识符
o Broadband repeat indicator
o 宽带重复指示符
o Restart indicator
o 重启指示器
o Broadband sending complete
o 宽带发送完成
o Transit network selection
o 公交线网选择
o Endpoint reference
o 端点引用
o Endpoint state
o 端点状态
The SETUP and ADD PARTY messages in the ST2+ over ATM protocol must include an ATM adaptation layer parameters information element. The CONNECT message may or may not include this element. The coding rules for the fields are as follows.
ST2+over ATM协议中的设置和添加方消息必须包括ATM适配层参数信息元素。连接消息可能包含也可能不包含此元素。字段的编码规则如下所示。
o The AAL Type is set to AAL5.
o AAL类型设置为AAL5。
o The value of the Forward maximum CPCS size field is set to the same as that of the MaxMsgSize field in the CONNECT SCMP message corresponding to the SETUP or ADD PARTY message.
o 向前最大CPCS大小字段的值设置为与设置或添加方消息对应的CONNECT SCMP消息中的MaxMsgSize字段的值相同。
o If the VC is established as a point-to-point call, the value of the Backward maximum CPCS size field is set the same as that of the Forward maximum CPCS size field. If the VC is established as a point-to-multipoint call, the value of the Backward maximum CPCS size field is set to zero.
o 如果VC建立为点对点调用，则向后最大CPCS大小字段的值设置为与向前最大CPCS大小字段的值相同。如果VC建立为点对多点调用，则向后最大CPCS大小字段的值设置为零。
o The SSCS type is set to null.
o SSCS类型设置为空。
If the Null FlowSpec is specified in the ST2+ over ATM protocol, the coding rules for the fields in the ATM traffic descriptor information element in the SETUP message are as follows.
如果在ST2+over ATM协议中指定了空流规范，则设置消息中ATM流量描述符信息元素中字段的编码规则如下所示。
o The value of the Forward PCR (CLP=0+1) field depends on the specification of the ATM network. The Forward PCR (CLP=0+1) field in each ATM interface in an implementation must be configurable to any value between zero and 16,777,215.
o 前向PCR（CLP=0+1）字段的值取决于ATM网络的规格。实现中每个ATM接口中的前向PCR（CLP=0+1）字段必须可配置为0到16777215之间的任何值。
o If the VC is established as a point-to-point call, the value of the Backward PCR (CLP=0+1) field is set the same as that of the Forward PCR (CLP=0+1) field. If the VC is established as a point-to-multipoint call, the value of the Backward PCR (CLP=0+1) field is set to zero.
o 如果VC建立为点对点调用，则向后PCR（CLP=0+1）字段的值设置为与向前PCR（CLP=0+1）字段的值相同。如果VC建立为点对多点调用，则反向PCR（CLP=0+1）字段的值设置为零。
o The Best effort indication must be present.
o 必须提供最大努力指示。
If the Controlled-Load Service FlowSpec is specified, the coding rules for the fields are as follows.
如果指定了受控负载服务流程规范，则字段的编码规则如下所示。
o The value of the Forward PCR (CLP=0+1) field depends on the specification of the ATM network. The Forward PCR (CLP=0+1) field in each ATM interface in an implementation must be configurable to any value between zero and 16,777,215.
o 前向PCR（CLP=0+1）字段的值取决于ATM网络的规格。实现中每个ATM接口中的前向PCR（CLP=0+1）字段必须可配置为0到16777215之间的任何值。
o If the VC is established as a point-to-point call, the value of the Backward PCR (CLP=0+1) field is set the same as that of the Forward PCR (CLP=0+1) field. If the VC is established as a point-to-multipoint call, the value of the Backward PCR (CLP=0+1) field is set to zero.
o 如果VC建立为点对点调用，则向后PCR（CLP=0+1）字段的值设置为与向前PCR（CLP=0+1）字段的值相同。如果VC建立为点对多点调用，则反向PCR（CLP=0+1）字段的值设置为零。
o The method for calculating the Forward SCR (CLP=0+1) field is shown in section 5.
o 计算正向SCR（CLP=0+1）字段的方法如第5节所示。
o If the VC is established as a point-to-point call, the value of the Backward SCR (CLP=0+1) field is set the same as that of the Forward SCR (CLP=0+1) field. If the VC is established as a point-to-multipoint call, this field must not be present.
o 如果VC建立为点对点调用，则向后SCR（CLP=0+1）字段的值设置为与向前SCR（CLP=0+1）字段的值相同。如果VC建立为点对多点调用，则此字段不得存在。
o The method for calculating the Forward MBS (CLP=0+1) field is shown in section 5.
o 计算前向MBS（CLP=0+1）字段的方法如第5节所示。
o If the VC is established as a point-to-point call, the value of the Backward MBS (CLP=0+1) field is set the same as that of the Forward MBS (CLP=0+1) field. If the VC is established as a point-to-multipoint call, this field must not be present.
o 如果VC建立为点对点调用，则向后MBS（CLP=0+1）字段的值设置为与向前MBS（CLP=0+1）字段的值相同。如果VC建立为点对多点调用，则此字段不得存在。
o The Best effort indication, Tagging backward, and Tagging forward fields must not be present.
o 最大努力指示、向后标记和向前标记字段不得存在。
If the Null FlowSpec is specified in the ST2+ over ATM protocol, the coding rules for the fields in the Broadband bearer capability information element in the SETUP message are as follows.
如果在ST2+over ATM协议中指定了空FlowSpec，则设置消息中宽带承载能力信息元素中字段的编码规则如下所示。
o The Bearer class depends on the specification of the ATM network. The Bearer class in each ATM interface in an implementation must be configurable as either BCOB-X or BCOB-C. BCOB-X is recommended as the default configuration.
o 承载类取决于ATM网络的规格。实现中每个ATM接口中的承载类必须可配置为BCOB-X或BCOB-C。建议将BCOB-X作为默认配置。
o The Traffic type and Timing requirements fields must not be present.
o 交通类型和时间要求字段不得存在。
o The Susceptibility to clipping field is set to not susceptible to clipping.
o “易受剪裁影响”字段设置为“不易受剪裁影响”。
o If the VC is established as a point-to-point call, the User plane connection configuration field is set to point-to-point, and if the VC is established as a point-to-multipoint call, it is set to point-to-multipoint.
o 如果VC建立为点对点调用，则用户平面连接配置字段设置为点对点，如果VC建立为点对多点调用，则设置为点对多点。
If the Controlled-Load Service FlowSpec is specified, the coding rules for the fields are as follows.
如果指定了受控负载服务流程规范，则字段的编码规则如下所示。
o The Bearer class depends on the specification of the ATM network. The Bearer class in each ATM interface in an implementation must be configurable as either BCOB-X or BCOB-C. BCOB-X is recommended as the default configuration.
o 承载类取决于ATM网络的规格。实现中每个ATM接口中的承载类必须可配置为BCOB-X或BCOB-C。建议将BCOB-X作为默认配置。
o If the Bearer class is BCOB-X, the Traffic type and Timing requirements fields depend on the specification of the ATM network. The Traffic type and Timing requirements fields in each ATM interface in an implementation must be configurable as either no indication or VBR and Not required, respectively. No indication is recommended as the default configuration. If the Bearer class is BCOB-C, the Traffic type and Timing requirements fields must not be present.
o 如果承载类别为BCOB-X，则业务类型和定时要求字段取决于ATM网络的规范。实现中每个ATM接口中的流量类型和定时要求字段必须分别配置为无指示或VBR和Not required。不建议将任何指示作为默认配置。如果承载类别为BCOB-C，则不得存在“业务类型”和“定时要求”字段。
o The Susceptibility to clipping field depends on the specification of the ATM network. The Susceptibility to clipping field in each ATM interface in an implementation must be configurable as either not susceptible to clipping or susceptible to clipping. Not susceptible to clipping is recommended as the default configuration.
o 对削波场的敏感性取决于ATM网络的规格。实现中每个ATM接口中的易受剪裁影响字段必须可配置为不易受剪裁影响或易受剪裁影响。建议将不受剪裁影响作为默认配置。
o If the VC is established as a point-to-point call, the User plane connection configuration field is set to point-to-point, and if the VC is established as a point-to-multipoint call, it is set to point-to-multipoint.
o 如果VC建立为点对点调用，则用户平面连接配置字段设置为点对点，如果VC建立为点对多点调用，则设置为点对多点。
The SETUP and ADD PARTY messages in the ST2+ over ATM protocol must include a Broadband high layer information information element. The coding rules for the fields are as follows.
ST2+over ATM协议中的设置和添加方消息必须包括宽带高层信息元素。字段的编码规则如下所示。
o The High layer information type is set to User specific.
o 高层信息类型设置为用户特定。
o The first 6 bytes in the High layer information field are set to the SID of the stream corresponding to the VC.
o 高层信息字段中的前6个字节被设置为与VC对应的流的SID。
The SETUP and ADD PARTY messages in the ST2+ over ATM protocol must include a Broadband low layer information information element. The CONNECT message may or may not include this element. The coding rules for the fields are as follows.
ST2+over ATM协议中的设置和添加方消息必须包括宽带低层信息元素。连接消息可能包含也可能不包含此元素。字段的编码规则如下所示。
o The User information layer 3 protocol field is set to ISO/IEC TR 9577.
o 用户信息第3层协议字段设置为ISO/IEC TR 9577。
o The IPI field is set to IEEE 802.1 SNAP (0x80).
o IPI字段设置为IEEE 802.1快照（0x80）。
o The OUI field is set to IANA (0x00-00-5E).
o OUI字段设置为IANA（0x00-00-5E）。
o The PID field is set to ST2+ (TBD).
o PID字段设置为ST2+（待定）。
If the Null FlowSpec is specified in the ST2+ over ATM protocol, the coding rules for the fields in the QoS parameter in the SETUP message are as follows.
如果在ST2+over ATM协议中指定了空FlowSpec，则设置消息中QoS参数字段的编码规则如下所示。
o The QoS class forward and QoS class backward fields are set to QoS class 0.
o QoS类向前和QoS类向后字段设置为QoS类0。
If the Controlled-Load Service FlowSpec is specified, the coding rules for the fields are as follows.
如果指定了受控负载服务流程规范，则字段的编码规则如下所示。
o The QoS class forward and QoS class backward fields depend on the specification of the ATM network. The QoS class forward and QoS class backward fields in each ATM interface in an implementation must be configurable as either QoS class 0 or QoS class 3. QoS class 0 is recommended as the default configuration.
o QoS类向前和QoS类向后字段取决于ATM网络的规范。实现中每个ATM接口中的QoS类向前和QoS类向后字段必须可配置为QoS类0或QoS类3。建议将QoS等级0作为默认配置。
The ST2+ over ATM protocol modifies RFC 1819 ST2+ protocol, but basically these modifications are minimum extensions for ATM support and bug fixes, so they do not weaken the security of the ST2+ protocol.
ST2+over ATM协议修改了RFC 1819 ST2+协议，但基本上这些修改是对ATM支持和错误修复的最小扩展，因此它们不会削弱ST2+协议的安全性。
The ST2+ over ATM protocol specifies protocol interaction between ST2+ and UNI 3.1, and this does not weaken the security of the UNI 3.1 protocol.
ATM上的ST2+协议规定了ST2+和UNI 3.1之间的协议交互，这不会削弱UNI 3.1协议的安全性。
In an ST2+ agent that processes an incoming call of SVC, if the incoming SETUP message contains the calling party number and if it is verified and passed by the ATM network or it is provided by the
在处理SVC传入呼叫的ST2+代理中，如果传入设置消息包含主叫方号码，并且ATM网络验证并传递了该号码，或者由
network, then it is feasible to use the calling party number for part of the calling party authentication to strengthen security.
网络中，则可以使用主叫方号码进行部分主叫方身份验证，以增强安全性。
References
工具书类
[1] Borden, M., Crawley, E., Davie, B., and S. Batsell, "Integration of Real-time Services in an IP-ATM Network Architecture", RFC 1821, August 1995.
[1] Borden，M.，Crawley，E.，Davie，B.，和S.Batsell，“IP-ATM网络架构中的实时服务集成”，RFC 18211995年8月。
[2] Jackowski, S., "Native ATM Support for ST2+", RFC 1946, May 1996.
[2] Jackowski，S.，“ST2+的本机ATM支持”，RFC 1946，1996年5月。
[3] S. Damaskos and A. Gavras, "Connection Oriented Protocols over ATM: A case study", Proc. SPIE, Vol. 2188, pp.226-278, February 1994.
[3] S.Damaskos和A.Gavras，“ATM上面向连接的协议：案例研究”，Proc。SPIE，第2188卷，第226-278页，1994年2月。
[4] Delgrossi, L., and L. Berger, Ed., "Internet Stream Protocol Version 2 (ST2) Protocol Specification - Version ST2+", RFC 1819, August 1995.
[4] Delgrossi，L.和L.Berger，编辑，“互联网流协议版本2（ST2）协议规范-版本ST2+”，RFC 18191995年8月。
[5] Wroclawski, J., "Specification of the Controlled-Load Network Element Service", RFC 2211, September 1997.
[5] Wroclawski，J.，“受控负荷网元服务规范”，RFC2211，1997年9月。
[6] Shenker, S., Partridge, C., and R. Guerin, "Specification of Guaranteed Quality of Service", RFC 2212, September 1997.
[6] Shenker，S.，Partridge，C.和R.Guerin，“保证服务质量规范”，RFC 2212，1997年9月。
[7] Wroclawski, J., "The Use of RSVP with IETF Integrated Services", RFC 2210, September 1997.
[7] Wroclawski，J.，“RSVP与IETF综合服务的使用”，RFC 2210，1997年9月。
[8] Garrett, M., and M. Borden, "Interoperation of Controlled-Load Service and Guaranteed Service with ATM", RFC 2381, August 1998.
[8] Garrett，M.和M.Borden，“受控负载服务和保证服务与ATM的互操作”，RFC 2381，1998年8月。
[9] Ghanwani, A., Pace, J., and V. Srinivasan, "A Framework for Providing Integrated Services Over Shared and Switched LAN Technologies", Work in Progress.
[9] Ghanwani，A.，Pace，J.，和V.Srinivasan，“通过共享和交换LAN技术提供综合服务的框架”，正在进行中。
[10] The ATM Forum, "ATM User-Network Interface Specification Version 3.1", September 1994.
[10] ATM论坛，“ATM用户网络接口规范3.1版”，1994年9月。
[11] The ATM Forum, "ATM User-Network Interface (UNI) Signaling Specification Version 4.0", af-sig-0061.000, July 1996.
[11] ATM论坛，“ATM用户网络接口（UNI）信令规范版本4.0”，af-sig-0061.000，1996年7月。
[12] ITU-T, "Broadband Integrated Services Digital Network (B-ISDN)- Digital Subscriber Signaling System No. 2 (DSS 2)-User-Network Interface (UNI) Layer 3 Specification for Basic Call/Connection Control", ITU-T Recommendation Q.2931, September 1995.
[12] ITU-T，“宽带综合业务数字网（B-ISDN）-第2号数字用户信令系统（DSS2）-基本呼叫/连接控制的用户网络接口（UNI）第3层规范”，ITU-T建议Q.2931995年9月。
[13] ITU-T, "Broadband Integrated Services Digital Network (B-ISDN)- Digital Subscriber Signaling System No. 2 (DSS 2)-User-Network Interface Layer 3 Specification for Point-to-Multipoint Call/Connection Control", ITU-T Recommendation Q.2971, October 1995.
[13] ITU-T，“宽带综合业务数字网（B-ISDN）-第2号数字用户信令系统（DSS 2）-点对多点呼叫/连接控制的用户网络接口层3规范”，ITU-T建议Q.2971，1995年10月。
[14] ITU-T, "B-ISDN Protocol Reference Model and its Application", CCITT Recommendation I.321, April 1991.
[14] ITU-T，“B-ISDN协议参考模型及其应用”，CCITT建议I.321，1991年4月。
[15] ITU-T, "B-ISDN ATM Adaptation Layer (AAL) type 5 specification", Draft new ITU-T Recommendation I.363.5, September 1995.
[15] ITU-T，“B-ISDN ATM适配层（AAL）第5类规范”，新的ITU-T建议I.363.5草案，1995年9月。
[16] Heinanen, J., "Multiprotocol Encapsulation over ATM Adaptation Layer 5", RFC 1483, July 1993.
[16] Heinanen，J.，“ATM适配层5上的多协议封装”，RFC 1483，1993年7月。
[17] Laubach, M., "Classical IP and ARP over ATM", RFC 1577, January 1994.
[17] Laubach，M.，“ATM上的经典IP和ARP”，RFC 1577，1994年1月。
[18] Perez, M., Liaw, F., Mankin, A., Hoffman, E., Grossman, D., and A. Malis, "ATM Signaling Support for IP over ATM", RFC 1755, February 1995.
[18] Perez，M.，Liaw，F.，Mankin，A.，Hoffman，E.，Grossman，D.，和A.Malis，“ATM上IP的ATM信令支持”，RFC 17551995年2月。
[19] Luciani, J., Katz, D., Piscitello, D., and B. Cole, "NBMA Next Hop Resolution Protocol (NHRP)", RFC 2332, April 1998.
[19] Luciani，J.，Katz，D.，Piscitello，D.，和B.Cole，“NBMA下一跳解析协议（NHRP）”，RFC 2332，1998年4月。
Acknowledgments
致谢
ATM is a huge technology and without the help of many colleagues at NTT who are involved in ATM research and development, it would have been impossible for me to complete this protocol specification. I would like to thank Hideaki Arai and Naotaka Morita of the NTT Network Strategy Planning Dept., Shin-ichi Kuribayashi, Jun Aramomi, and Takumi Ohba of the NTT Network Service Systems Labs., and also Hisao Uose and Yoshikazu Oda of the NTT Multimedia Networks Labs. for their valuable comments and discussions.
ATM是一项庞大的技术，如果没有NTT许多参与ATM研发的同事的帮助，我就不可能完成这个协议规范。我要感谢NTT网络战略规划部的荒井秀明和森田直隆、NTT网络服务系统实验室的黑井信一、Aramomi Jun和Ohba Takumi，以及NTT多媒体网络实验室的大田久夫和小田佳彦。感谢他们的宝贵意见和讨论。
And I would also like to especially thank Eric Crawley of Gigapacket Networks, John Wroclawski of MIT, Steven Jackowski of Net Manage, Louis Berger of FORE Systems, Steven Willis of Bay Networks, Greg Burch of Qosnetics, and Denis Gallant, James Watt, and Joel Halpern of Newbridge Networks for their valuable comments and suggestions.
我还要特别感谢Gigapacket Networks的Eric Crawley、麻省理工学院的John Wroclawski、网络管理公司的Steven Jackowski、FORE Systems公司的Louis Berger、Bay Networks公司的Steven Willis、Qosnetics公司的Greg Burch以及新桥网络公司的Denis Gallant、James Watt和Joel Halpern，感谢他们提出的宝贵意见和建议。
Also this specification is based on various discussions during NTT Multimedia Joint Project with NACSIS. I would like to thank Professor Shoichiro Asano of the National Center for Science Information Systems for his invaluable advice in this area.
此外，本规范基于NTT多媒体与NACSIS联合项目期间的各种讨论。我要感谢国家科学信息系统中心的浅野昭一教授在这方面提出的宝贵建议。
Author's Address
作者地址
Muneyoshi Suzuki NTT Multimedia Networks Laboratories 3-9-11, Midori-cho Musashino-shi, Tokyo 180-8585, Japan
Muneyoshi Suzuki NTT多媒体网络实验室3-9-11，Midori cho Musashino shi，东京180-8585
Phone: +81-422-59-2119
Fax: +81-422-59-2829
EMail: suzuki@nal.ecl.net
Phone: +81-422-59-2119
Fax: +81-422-59-2829
EMail: suzuki@nal.ecl.net
Appendix A. RFC 1819 ST2+ Errata
附录A.RFC 1819 ST2+勘误表
The following sentence in the second paragraph:
第二段中的以下句子：
< For some SCMP messages (CONNECT, CHANGE, JOIN, and STATUS) the
<对于某些SCMP消息（连接、更改、加入和状态），请
should be changed to
应改为
> For some SCMP messages (CONNECT, CHANGE, and JOIN) the
>对于某些SCMP消息（连接、更改和加入）
The following sentence:
以下一句：
< option can be included with ACCEPT, CHANGE, CONNECT, DISCONNECT, and < REFUSE messages. The format of the UserData parameter is shown in
<选项可包含在接受、更改、连接、断开和<拒绝消息中。UserData参数的格式如所示
should be changed to
应改为
> option can be included with ACCEPT, CHANGE, CONNECT, DISCONNECT, NOTIFY, > and REFUSE messages. The format of the UserData parameter is shown in
>选项可包含在接受、更改、连接、断开连接、通知、>和拒绝消息中。UserData参数的格式如所示
The following sentence:
以下一句：
< CONNECT with a REFUSE message with the affected targets specified in < the TargetList and an appropriate ReasonCode (StreamExists).
<使用拒绝消息连接，<目标列表中指定的受影响目标，并使用适当的推理代码（StreamExists）。
should be changed to
应改为
> CONNECT with a REFUSE message with the affected targets specified in > the TargetList and an appropriate ReasonCode (TargetExists).
>连接带有在>TargetList中指定的受影响目标的拒绝消息和适当的ReasonCode（TargetExists）。
The following sentence:
以下一句：
< notifies the processing ST agent which should respond with ReasonCode < (FlowSpecMismatch).
<通知处理ST代理，该代理应使用ReasonCode<（FlowSpecMismatch）进行响应。
should be changed to
应改为
> notifies the processing ST agent which should respond with a REFUSE > message with ReasonCode (FlowSpecMismatch).
>通知处理ST代理，该代理应使用ReasonCode（FlowSpecMismatch）以拒绝>消息进行响应。
The following sentence:
以下一句：
< some time after a failure. As a result, the ST agent attempting the < recovery may receive ERROR messages for the new CONNECTs that are < ... < failure, and will interpret the new CONNECT as resulting from a < routing failure. It will respond with an ERROR message with the < appropriate ReasonCode (StreamExists). Since the timeout that the ST < ... < remnants of the broken stream will soon be torn down by a DISCONNECT < message. Therefore, the ST agent that receives the ERROR message with < ReasonCode (StreamExists) should retransmit the CONNECT message after
<失败后一段时间。因此，尝试<恢复的ST代理可能会收到<…<新连接的错误消息失败，并将新连接解释为路由失败。它将以一条带有<property ReasonCode（streamxists）的错误消息进行响应。自ST<…<断流的残余物将很快被一条断开连接的消息拆下。因此，接收带有<ReasonCode（streamxists）的错误消息的ST代理应在
should be changed to
应改为
> some time after a failure. As a result, the ST agent attempting the > recovery may receive REFUSE messages for the new CONNECTs that are > ... > failure, and will interpret the new CONNECT as resulting from a > routing failure. It will respond with a REFUSE message with the > appropriate ReasonCode (TargetExists). Since the timeout that the ST > ... > remnants of the broken stream will soon be torn down by a DISCONNECT > message. Therefore, the ST agent that receives the REFUSE message with > ReasonCode (TargetExists) should retransmit the CONNECT message after
>失败后的一段时间。因此，尝试>恢复的ST代理可能会收到>的新连接的拒绝消息失败，并将新连接解释为>路由失败的结果。它将用带有>适当原因代码（TargetExists）的拒绝消息进行响应。自ST>..>断开连接>消息将很快清除断开的流的残余。因此，接收带有>ReasonCode（TargetExists）的拒绝消息的ST代理应在
The following sentence:
以下一句：
< (least important) to 256 (most important). This value is
<（最不重要）至256（最重要）。此值为
should be changed to
应改为
> (least important) to 255 (most important). This value is
>（最不重要）到255（最重要）。此值为
The following sentence:
以下一句：
<o Reference is a transaction number. Each sender of a request control < message assigns a Reference number to the message that is unique < with respect to the stream.
<o参考是一个交易编号。请求控制<消息的每个发送者为消息分配一个参考编号，该编号相对于流而言是唯一的<。
should be changed to
应改为
>o Reference is a transaction number. Each sender of a request control > message assigns a Reference number to the message that is unique > with respect to the stream for messages generated by each agent.
>o参考是一个交易编号。请求控制>消息的每个发送者为消息分配一个参考号，该参考号相对于每个代理生成的消息流而言是唯一的>。
The following:
以下是：
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< | PCode = 5 | PBytes | NextPcol |OriginSAPBytes |
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< | PCode = 5 | PBytes | NextPcol |OriginSAPBytes |
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
should be changed to
应改为
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | PCode = 4 | PBytes | NextPcol |OriginSAPBytes |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | PCode = 4 | PBytes | NextPcol |OriginSAPBytes |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The following sentence:
以下一句：
<o IPHops is the number of IP encapsulated hops traversed by the < stream. This field is set to zero by the origin, and is incremented < at each IP encapsulating agent.
<o IPHops是<流通过的IP封装跃点数。该字段由原点设置为零，并在每个IP封装代理处递增<。
should be changed to
应改为
>o IPHops is the number of IP encapsulated hops traversed by the > stream.
>o IPHops是>流通过的IP封装跃点的数量。
The following:
以下是：
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< | OpCode = 2 | 0 | TotalBytes |
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< | OpCode = 2 | 0 | TotalBytes |
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
should be changed to
应改为
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | OpCode = 2 | 0 | TotalBytes = 16 |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | OpCode = 2 | 0 | TotalBytes = 16 |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The following sentence:
以下一句：
<o I (bit 7) is used to indicate that the LRM is permitted to interrupt
<o I（位7）用于指示允许LRM中断
should be changed to
应改为
>o I (bit 9) is used to indicate that the LRM is permitted to interrupt
>o I（位9）用于指示允许LRM中断
The following:
以下是：
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< | OpCode = 7 |R| 0 | TotalBytes |
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
< | OpCode = 7 |R| 0 | TotalBytes |
< +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
should be changed to
应改为
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | OpCode = 7 |R| 0 | TotalBytes = 20 |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | OpCode = 7 |R| 0 | TotalBytes = 20 |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The following sentence:
以下一句：
<o Reference contains a number assigned by the ST agent sending the < REFUSE for use in the acknowledging ACK.
<o参考包含ST代理分配的编号，ST代理发送<拒绝以用于确认ACK。
should be changed to
应改为
>o Reference contains a number assigned by the ST agent sending the > JOIN-REJECT for use in the acknowledging ACK.
>o参考包含ST代理分配的编号，ST代理发送>加入-拒绝以用于确认确认确认。
The following sentence:
以下一句：
< possibly Groups of the stream. It the full target list can not fit in
<可能是流的组。如果没有完整的目标列表，可能无法容纳
should be changed to
应改为
> possibly Groups of the stream. If the full target list can not fit in
>可能是一组组流。如果无法容纳完整的目标列表
The following:
以下是：
< 32 PCodeUnknown Control PDU has a parameter with an invalid < PCode.
<32 PCodeUnknown控件PDU的参数具有无效的<PCode。
should be removed because a common SCMP element with an unknown PCode is equivalent to the UserData (RFC 1819, Section 10.3.8).
应删除，因为具有未知PCode的公共SCMP元素等同于用户数据（RFC 1819，第10.3.8节）。
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完整版权声明
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