Network Working Group A. G. Malis
Request for Comments: 3496 T. Hsiao
Category: Informational Vivace Networks
March 2003
Network Working Group A. G. Malis
Request for Comments: 3496 T. Hsiao
Category: Informational Vivace Networks
March 2003
Protocol Extension for Support of Asynchronous Transfer Mode (ATM) Service Class-aware Multiprotocol Label Switching (MPLS) Traffic Engineering
支持异步传输模式（ATM）服务类感知多协议标签交换（MPLS）流量工程的协议扩展
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 (2003). All Rights Reserved.
版权所有（C）互联网协会（2003年）。版权所有。
Abstract
摘要
This document specifies a Resource ReSerVation Protocol-Traffic Engineering (RSVP-TE) signaling extension for support of Asynchronous Transfer Mode (ATM) Service Class-aware Multiprotocol Label Switching (MPLS) Traffic Engineering.
本文件规定了一种资源预留协议流量工程（RSVP-TE）信令扩展，用于支持异步传输模式（ATM）服务类感知多协议标签交换（MPLS）流量工程。
Table of Contents
目录
1. Overview......................................................2
2. Extended RSVP-TE Path Message Format..........................2
2.1 PATH Message Format.......................................3
3. ATM_SERVICECLASS Object.......................................3
4. Handling the ATM_SERVICECLASS Object..........................4
5. Non-support of the ATM_SERVICECLASS Object....................4
6. Security Considerations.......................................4
7. IANA Considerations...........................................5
8. References....................................................5
9. Authors' Addresses............................................5
10. Full Copyright Statement......................................6
1. Overview......................................................2
2. Extended RSVP-TE Path Message Format..........................2
2.1 PATH Message Format.......................................3
3. ATM_SERVICECLASS Object.......................................3
4. Handling the ATM_SERVICECLASS Object..........................4
5. Non-support of the ATM_SERVICECLASS Object....................4
6. Security Considerations.......................................4
7. IANA Considerations...........................................5
8. References....................................................5
9. Authors' Addresses............................................5
10. Full Copyright Statement......................................6
This document defines a Resource ReSerVation Protocol-Traffic Engineering (RSVP-TE) protocol addition to support ATM (Asynchronous Transfer Mode) Service Class-aware MPLS (MultiProtocol Label Switching) Traffic Engineering.
本文档定义了资源预留协议流量工程（RSVP-TE）协议，以支持ATM（异步传输模式）服务类感知MPLS（多协议标签交换）流量工程。
This protocol addition is used with all MPLS Label Switched Routers (LSRs) and link types (including, but not restricted to, Packet over SONET, Ethernet, and ATM links) to signal traffic engineered paths that can support the ATM service classes as defined by the ATM Forum [TM]. This document does not specify HOW to actually implement the functionality in the MPLS LSRs to emulate the ATM Forum service classes (such as necessary queuing and scheduling mechanisms), only how to signal that the TE path must support the ATM Forum service classes. A useful application for such paths is the carriage of ATM cells encapsulated in IP or MPLS packets in order to use MPLS networks as functional replacements for ATM networks.
此协议添加用于所有MPLS标签交换路由器（LSR）和链路类型（包括但不限于SONET上的数据包、以太网和ATM链路），以信号流量工程路径，可支持ATM论坛[TM]定义的ATM服务类别。本文档未指定如何实际实现MPLS LSR中的功能以模拟ATM论坛服务类（如必要的排队和调度机制），仅说明如何发出TE路径必须支持ATM论坛服务类的信号。这种路径的一个有用应用是携带封装在IP或MPLS数据包中的ATM信元，以便使用MPLS网络作为ATM网络的功能替代品。
One new RSVP-TE Object is defined in this document: the ATM_SERVICECLASS Object. Detailed description of this Object is provided below. This new Object is applicable to PATH messages. This specification only defines the use of the ATM_SERVICECLASS Object in PATH messages used to establish LSP (Label Switched Path) Tunnels in accordance with [RSVP-TE]. Such PATH messages contain a Session Object with a C-Type equal to LSP_TUNNEL_IPv4 and a LABEL_REQUEST object.
本文定义了一个新的RSVP-TE对象：ATM_SERVICECLASS对象。下文提供了该对象的详细说明。此新对象适用于路径消息。本规范仅定义了根据[RSVP-TE]在用于建立LSP（标签交换路径）隧道的路径消息中使用ATM_SERVICECLASS对象。这样的路径消息包含一个C类型等于LSP_TUNNEL_IPv4的会话对象和一个LABEL_请求对象。
Restrictions defined in [RSVP-TE] for support of establishment of LSP Tunnels via RSVP-TE are also applicable to the establishment of LSP Tunnels supporting ATM Service Class-aware traffic engineering. For instance, only unicast LSPs are supported and Multicast LSPs are for further study.
[RSVP-TE]中定义的用于支持通过RSVP-TE建立LSP隧道的限制也适用于支持ATM服务等级感知流量工程的LSP隧道的建立。例如，仅支持单播LSP，多播LSP有待进一步研究。
This new ATM_SERVICECLASS object is optional with respect to RSVP-TE so that general RSVP-TE implementations not concerned with ATM Service Class-aware traffic engineering MPLS LSP setup do not have to support this object.
这个新的ATM_SERVICECLASS对象对于RSVP-TE是可选的，因此与ATM服务类感知流量工程MPLS LSP设置无关的一般RSVP-TE实现不必支持此对象。
The format of the extended PATH message is as follows:
扩展路径消息的格式如下所示：
<PATH Message> ::= <Common Header> [ <INTEGRITY> ]
<SESSION> <RSVP_HOP>
<TIME_VALUES>
[ <EXPLICIT_ROUTE> ]
<LABEL_REQUEST>
[ <SESSION_ATTRIBUTE> ]
[ <DIFFSERV> ]
[ <ATM_SERVICECLASS> ]
[ <POLICY_DATA> ... ]
[ <sender descriptor> ]
<PATH Message> ::= <Common Header> [ <INTEGRITY> ]
<SESSION> <RSVP_HOP>
<TIME_VALUES>
[ <EXPLICIT_ROUTE> ]
<LABEL_REQUEST>
[ <SESSION_ATTRIBUTE> ]
[ <DIFFSERV> ]
[ <ATM_SERVICECLASS> ]
[ <POLICY_DATA> ... ]
[ <sender descriptor> ]
<sender descriptor> ::= <SENDER_TEMPLATE> [ <SENDER_TSPEC> ]
[ <ADSPEC> ]
[ <RECORD_ROUTE> ]
<sender descriptor> ::= <SENDER_TEMPLATE> [ <SENDER_TSPEC> ]
[ <ADSPEC> ]
[ <RECORD_ROUTE> ]
The ATM_SERVICECLASS object format is as follows:
ATM_SERVICECLASS对象格式如下：
Class Number = 227, C_Type = 1
类别编号=227，C_类型=1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | SC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | SC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Reserved : 29 bits This field is reserved. It must be set to zero on transmission and must be ignored on receipt.
保留：29位此字段保留。传输时必须将其设置为零，接收时必须忽略。
SC : 3 bits Indicates the ATM Service Class. Values currently allowed are: 0: UBR (Unspecified Bit Rate) 1: VBR-NRT (Variable Bit Rate, Non-Real Time) 2: VBR-RT (Variable Bit Rate, Real Time) 3: CBR (Constant Bit Rate) 4-7: reserved
SC:3位表示ATM服务等级。当前允许的值为：0:UBR（未指定比特率）1:VBR-NRT（可变比特率，非实时）2:VBR-RT（可变比特率，实时）3:CBR（恒定比特率）4-7：保留
To establish an LSP tunnel with RSVP-TE, the sender LSR creates a PATH message with a session type of LSP_Tunnel_IPv4 and with a LABEL_REQUEST object as per [RSVP-TE]. The sender LSR may also include the DIFFSERV object as per [DIFF-MPLS].
要使用RSVP-TE建立LSP隧道，发送方LSR将创建一个会话类型为LSP_tunnel_IPv4的路径消息，并根据[RSVP-TE]创建一个LABEL_请求对象。发送方LSR还可以包括根据[DIFF-MPLS]的DIFFSERV对象。
If the LSP is associated with an ATM Service Class, the sender LSR must include the ATM_SERVICECLASS object in the PATH message with the Service-Class (SC) field set to signify the desired ATM Service Class.
如果LSP与ATM服务类别相关联，则发送方LSR必须在路径消息中包含ATM_SERVICECLASS对象，并将服务类别（SC）字段设置为表示所需的ATM服务类别。
If a path message contains multiple ATM_SERVICECLASS objects, only the first one is meaningful; subsequent ATM_SERVICECLASS object(s) must be ignored and must not be forwarded.
如果路径消息包含多个ATM_SERVICECLASS对象，则只有第一个对象有意义；必须忽略后续ATM_SERVICECLASS对象，且不得转发。
Each LSR along the path that is ATM_SERVICECLASS-aware records the ATM_SERVICECLASS object, when present, in its path state block.
ATM_SERVICECLASS感知路径上的每个LSR将ATM_SERVICECLASS对象（如果存在）记录在其路径状态块中。
The destination LSR responds to the PATH message by sending a RESV message without an ATM_SERVICECLASS object (whether the PATH message contained an ATM_SERVICECLASS object or not).
目标LSR通过发送不带ATM_SERVICECLASS对象的RESV消息（无论路径消息是否包含ATM_SERVICECLASS对象）来响应PATH消息。
An LSR that does not recognize the ATM_SERVICECLASS object Class Number must behave in accordance with the procedures specified in [RSVP] for an unknown Class Number with the binary format 11bbbbbb, where b=0 or 1 (i.e., RSVP will ignore the object but forward it unexamined and unmodified).
不识别ATM_SERVICECLASS对象类号的LSR必须按照[RSVP]中针对二进制格式为11bbbbbb的未知类号指定的程序进行操作，其中b=0或1（即，RSVP将忽略该对象，但未经检查和修改就转发它）。
An LSR that recognizes the ATM_SERVICECLASS object Class Number but does not recognize the ATM_SERVICECLASS object C-Type, must behave in accordance with the procedures specified in [RSVP] for an unknown C-type (i.e., it must send a PathErr with the error code 'Unknown object C-Type' toward the sender).
识别ATM_SERVICECLASS对象类编号但不识别ATM_SERVICECLASS对象C-Type的LSR必须按照[RSVP]中为未知C-Type指定的程序进行操作（即，它必须向发送方发送错误代码为“unknown object C-Type”的PathErr）。
In both situations, this causes the path setup to fail. The sender should notify management that a LSP cannot be established and possibly might take action to retry reservation establishment without the ATM_SERVICECLASS object.
在这两种情况下，这都会导致路径设置失败。发送方应通知管理层无法建立LSP，并可能采取措施在没有ATM_SERVICECLASS对象的情况下重试保留建立。
The solution is not expected to add specific security requirements beyond those of Diff-Serv and existing TE. The security mechanisms currently used with Diff-Serv and existing TE can be used with this solution.
除了Diff-Serv和现有的TE之外，该解决方案预计不会添加特定的安全需求。当前与Diff Serv和现有TE一起使用的安全机制可以与此解决方案一起使用。
The IANA has registered a new RSVP Class Number for ATM_SERVICECLASS (227). (See http://www.iana.org/assignments/rsvp-parameters).
IANA已为ATM_SERVICECLASS（227）注册了一个新的RSVP类别号。（见http://www.iana.org/assignments/rsvp-parameters).
[DIFF-MPLS] Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen, P., Krishnan, R., Cheval, P. and J. Heinanen, "Multi-Protocol Label Switching (MPLS) Support of Differentiated Services", RFC 3270, May 2002.
[DIFF-MPLS]Le Faucheur，F.，Wu，L.，Davie，B.，Davari，S.，Vaananen，P.，Krishnan，R.，Cheval，P.和J.Heinanen，“区分服务的多协议标签交换（MPLS）支持”，RFC 32702002年5月。
[RSVP] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S. and S. Jazmin , "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997.
[RSVP]Braden，R.，Ed.，Zhang，L.，Berson，S.，Herzog，S.和S.Jazmin，“资源预留协议（RSVP）——第1版功能规范”，RFC 22052997年9月。
[RSVP-TE] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V. and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001.
[RSVP-TE]Awduche，D.，Berger，L.，Gan，D.，Li，T.，Srinivasan，V.和G.Swallow，“RSVP-TE：LSP隧道RSVP的扩展”，RFC 3209，2001年12月。
[TM] ATM Forum Traffic Management Specification Version 4.0, af-tm-0056.000, April 1996.
[TM]ATM论坛流量管理规范版本4.0，af-TM-0056.000，1996年4月。
Andrew G. Malis Vivace Networks, Inc. 2730 Orchard Parkway San Jose, CA 95134
Andrew G.Malis Vivace Networks，Inc.加利福尼亚州圣何塞市果园大道2730号，邮编95134
EMail: Andy.Malis@vivacenetworks.com
EMail: Andy.Malis@vivacenetworks.com
Tony Hsiao Vivace Networks, Inc. 2730 Orchard Parkway San Jose, CA 95134
萧东尼Vivace Networks，Inc.加利福尼亚州圣何塞市果园大道2730号，邮编95134
EMail: Tony.Hsiao@VivaceNetworks.com
EMail: Tony.Hsiao@VivaceNetworks.com
Copyright (C) The Internet Society (2003). All Rights Reserved.
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确认
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