Network Working Group K. Nagami
Request for Comments: 3038 Y. Katsube
Category: Standards Track Toshiba Corp.
N. Demizu
WaterSprings.ORG
H. Esaki
Univ. of Tokyo
P. Doolan
Ennovate Networks
January 2001
Network Working Group K. Nagami
Request for Comments: 3038 Y. Katsube
Category: Standards Track Toshiba Corp.
N. Demizu
WaterSprings.ORG
H. Esaki
Univ. of Tokyo
P. Doolan
Ennovate Networks
January 2001
VCID Notification over ATM link for LDP
LDP的ATM链路上的VCID通知
Status of this Memo
本备忘录的状况
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
本文件规定了互联网社区的互联网标准跟踪协议，并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态，请参考当前版本的“互联网官方协议标准”（STD 1）。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (2001). All Rights Reserved.
版权所有（C）互联网协会（2001年）。版权所有。
Abstract
摘要
The Asynchronous Transfer Mode Label Switching Router (ATM-LSR) is one of the major applications of label switching. Because the ATM layer labels (VPI and VCI) associated with a VC rewritten with new value at every ATM switch nodes, it is not possible to use them to identify a VC in label mapping messages. The concept of Virtual Connection Identifier (VCID) is introduced to solve this problem. VCID has the same value at both ends of a VC. This document specifies the procedures for the communication of VCID values between neighboring ATM-LSRs that must occur in order to ensure this property.
异步传输模式标签交换路由器（ATM-LSR）是标签交换的主要应用之一。由于与VC关联的ATM层标签（VPI和VCI）在每个ATM交换机节点上用新值重写，因此无法使用它们在标签映射消息中识别VC。为了解决这个问题，引入了虚拟连接标识符（VCID）的概念。VCID在VC的两端具有相同的值。本文件规定了相邻ATM LSR之间必须进行VCID值通信的程序，以确保该属性。
Several label switching schemes have been proposed to integrate Layer 2 and Layer 3. The ATM Label Switching Router (ATM-LSR) is one of the major applications of label switching.
已经提出了几种标签交换方案来集成第2层和第3层。ATM标签交换路由器（ATM-LSR）是标签交换的主要应用之一。
In the case of ATM VCs, the VPI and VCI labels are, in the general case, rewritten with new values at every switch node through which the VC passes and cannot be used to provide end to end identification of a VC.
对于ATM VCs，通常情况下，VPI和VCI标签在VC通过的每个交换机节点上用新值重写，并且不能用于提供VC的端到端标识。
In the context of MPLS 'stream', which are classes of packets that have some common characteristic that may be deduced by examination of the layer 3 header in the packets, are bound to layer 2 'labels'. We speak of stream being 'bound' to labels. These bindings are conveyed between peer LSRs by means of a Label Distribution Protocol [LDP].
In the context of MPLS 'stream', which are classes of packets that have some common characteristic that may be deduced by examination of the layer 3 header in the packets, are bound to layer 2 'labels'. We speak of stream being 'bound' to labels. These bindings are conveyed between peer LSRs by means of a Label Distribution Protocol [LDP].translate error, please retry
In order to apply MPLS to ATM links, we need some way to identify ATM VCs in LDP mapping messages. An identifier called a Virtual Connection ID (VCID) is introduced. VCID has the same value at both ends of a VC. This document specifies the procedures for the communication of VCID values between neighboring ATM-LSRs that must occur in order to ensure this property.
为了将MPLS应用于ATM链路，我们需要某种方法来识别LDP映射消息中的ATM VCs。引入了一个称为虚拟连接ID（VCID）的标识符。VCID在VC的两端具有相同的值。本文件规定了相邻ATM LSR之间必须进行VCID值通信的程序，以确保该属性。
The ATM has several types of VCs (transparent point-to-point link/VP/PVC/SVC). A transparent point-to-point link is defined as one that has the same VPI/VCI label at both ends of a VC. For example, two nodes are directly connected (i.e., without intervening ATM switches) or are connected through a VP with the same VPI value at both ends of the VP.
ATM有几种类型的VCs（透明点对点链路/VP/PVC/SVC）。透明点到点链路定义为在VC两端具有相同VPI/VCI标签的链路。例如，两个节点直接连接（即，不干预ATM交换机）或通过VP连接，VP两端的VPI值相同。
There are two broad categories of VCID notification procedures; inband and outband. The categorization refers to the connection over which the messages of the VCID notification procedure are forwarded. In the case of the inband procedures, those messages are forwarded over the VC to which they refer. In contrast the out of band procedures transmit the messages over some other connection (than the VC to which they refer).
VCID通知程序分为两大类；带内和带外。分类是指转发VCID通知过程消息的连接。对于带内过程，这些消息通过它们所指的VC转发。相比之下，带外过程通过其他连接（而不是它们所指的VC）传输消息。
We list below the various types of link and briefly mention the VCID notification procedures employed and the rational for that choice. The procedures themselves are discussed in detail in later sections.
我们在下面列出了各种类型的链接，并简要介绍了所采用的VCID通知程序以及该选择的合理性。这些程序本身将在后面的章节中详细讨论。
Transparent point-to-point link : no VCID notification VCID notification procedure is not necessary because the label (i.e., VPI/VCI) is the same at each end of the VC.
透明点对点链接：不需要VCID通知VCID通知程序，因为VC两端的标签（即VPI/VCI）相同。
VP : inband notification or VPID notification or no notification - Inband notification VCID notification is needed because the VPI at each end of the VC may not be the same. Inband VCID notification is used in this case.
VP：带内通知或VPID通知或无通知-需要带内通知VCID通知，因为VC两端的VPI可能不同。在这种情况下使用带内VCID通知。
- VPID notification VCID notification is needed because the VPI at each end of the VC may not be the same. VPID notification is used in this case.
- 需要VPID通知VCID通知，因为VC两端的VPI可能不同。在这种情况下使用VPID通知。
- No notification If a node has only one VP to a neighboring node, VCID notification procedure is not mandatory. The VCI can be used as the VCID. This is because the VCI value is the same at each end of the VP.
- 无通知如果一个节点与相邻节点只有一个VP，则VCID通知过程不是强制性的。VCI可用作VCID。这是因为VP两端的VCI值相同。
PVC : inband notification Inband VCID notification is used in this case because the labels at each end of the VC may not be the same.
PVC：带内通知在这种情况下使用带内VCID通知，因为VC两端的标签可能不同。
SVC : there are three possibilities - Outband notification If a signaling message has a field which is large enough to carry a VCID value (e.g., GIT [GIT]), then the VCID is carried directly in it.
SVC：有三种可能性-带外通知如果信令消息的字段足够大，可以携带VCID值（例如GIT[GIT]），那么VCID将直接携带在其中。
- Outband notification using a small-sized field If a signaling message has a field which is not large enough to carry a VCID value, this procedure is used.
- 使用小字段的带外通知如果信令消息的字段不足以承载VCID值，则使用此过程。
- Inband notification If a signaling message can not carry user information, this procedure is used.
- 带内通知如果信令消息不能承载用户信息，则使用此过程。
When an LSP is a point-to-multipoint VC and an ATM switch in an LSR is not capable of VC merge, it may cause problems in performance and quality of service. When the LSR wants to add a new leaf to the LSP, it needs to split the active LSP temporarily to send an inband notification message.
当LSP是点对多点VC且LSR中的ATM交换机不能进行VC合并时，可能会导致性能和服务质量问题。当LSR想要向LSP添加新叶时，它需要临时拆分活动LSP以发送带内通知消息。
A VC has a directionality. The VCID procedure for a VC is always triggered from the upstream node of the VC, i.e., the upstream node notifies the downstream node of the VCID.
风险投资具有方向性。VC的VCID过程始终从VC的上游节点触发，即上游节点将VCID通知下游节点。
If bidirectional use of a label switched VC is allowed, the label switched VC is said to be bidirectional. In this case, two VCID procedures are taken, one for each direction.
如果允许标签交换VC的双向使用，则标签交换VC称为双向。在这种情况下，采用两个VCID程序，每个方向一个。
If bidirectional use of a label switched VC is not allowed, the label switched VC is said to be unidirectional. In this case, only one VCID procedure is taken for the allowed direction.
如果不允许标签交换VC的双向使用，则称标签交换VC为单向。在这种情况下，只对允许的方向执行一个VCID程序。
VC directionality is communicated through LDP.
VC方向性通过LDP进行沟通。
VCID notification is performed by transmitting a control message through the VC newly established (by signalling or management) for use as an label switched path (LSP). The procedure for VCID notification between two nodes A and B is detailed below.
VCID通知通过新建立（通过信令或管理）的VC发送控制消息来执行，以用作标签交换路径（LSP）。下面详细说明两个节点A和B之间的VCID通知过程。
0. The node A establishes a VC to the destination node B (by signalling or management).
0. 节点A（通过信令或管理）建立到目的地节点B的VC。
1. The node A selects a VCID value.
1. 节点A选择VCID值。
2. The node A sends a VCID PROPOSE message which contains the VCID value and a message ID through the newly established VC to the node B.
2. 节点A通过新建立的VC向节点B发送包含VCID值和消息ID的VCID建议消息。
3. The node A establishes an association between the outgoing label (VPI/VCI) for the VC and the VCID value.
3. 节点A在VC的传出标签（VPI/VCI）和VCID值之间建立关联。
4. The node B receives the message from the VC and establishes an association between the VCID in the message and the incoming label(VPI/VCI) for the VC. Until the node B receives the LDP Request message, the node B discards any packet received over the VC other than the VCID PROPOSE message.
4. 节点B从VC接收消息，并在消息中的VCID与VC的传入标签（VPI/VCI）之间建立关联。在节点B接收到LDP请求消息之前，节点B丢弃通过VC接收的除VCID建议消息之外的任何分组。
5. The node B sends an ACK message to the node A. This message contains the same VCID and message ID as specified in the received message. This message is sent through the VC for LDP.
5. 节点B向节点A发送ACK消息。该消息包含与接收到的消息中指定的相同VCID和消息ID。此消息通过VC发送给LDP。
6. When node A receives the ACK message, it checks whether the VCID and the message ID in the message are the same as the registered ones. If they are the same, node A regards that node B has established the association between the VC and VCID. Otherwise, the message is ignored. If the node A does not receive the ACK message with the expected message ID and VCID during a given period, the node A resends the VCID PROPOSE message to the node B.
6. 当节点A接收到ACK消息时，它检查消息中的VCID和消息ID是否与注册的相同。如果它们相同，则节点A认为节点B已经在VC和VCID之间建立了关联。否则，该消息将被忽略。如果节点A在给定时段内没有接收到具有预期消息ID和VCID的ACK消息，则节点A将VCID建议消息重新发送给节点B。
7. After receiving the proposer ACK message, the node A sends an LDP REQUEST message to the node B. It contains the message ID used for VCID PROPOSE. When the node B receives the LDP REQUEST message, it regards that the node A has received the ACK correctly. The message exchange using VCID PROPOSE, VCID ACK, and LDP REQUEST messages constitutes a 3-way handshake. The 3-way handshake mechanism is required since the transmission of VCID
7. 在接收到提议者ACK消息之后，节点A向节点B发送LDP请求消息。该消息包含用于VCID提议的消息ID。当节点B接收到LDP请求消息时，它认为节点A已经正确地接收到ACK。使用VCID-PROPOSE、VCID-ACK和LDP请求消息的消息交换构成了一个3路握手。由于VCID的传输，因此需要3路握手机制
PROPOSE message is unreliable. Once the 3-way handshake completes, the node B ignores all VCID PROPOSE messages received over the VC. The node B sends an LDP Mapping message, which contains the VCID value in the label TLV.
“建议”消息不可靠。一旦三方握手完成，节点B将忽略通过VC接收的所有VCID建议消息。节点B发送LDP映射消息，该消息包含标签TLV中的VCID值。
Node A Node B
| |
|--------------->| VCID PROPOSE
| |
|<---------------| VCID ACK
| |
|--------------->| LDP Label Request
| |
|<---------------| LDP Label Mapping
Node A Node B
| |
|--------------->| VCID PROPOSE
| |
|<---------------| VCID ACK
| |
|--------------->| LDP Label Request
| |
|<---------------| LDP Label Mapping
Current LDP specification does not support multicast. But the VCID notification procedure is defined for future use. VCID notification is performed by sending a control message through the VC to be used as an LSP. The upstream node assigns the VCID value. The procedure by which it notifies the downstream node of that value is given below. The procedure is used when a new VC is created or a new leaf is added to the VC.
当前LDP规范不支持多播。但VCID通知程序是为将来使用而定义的。VCID通知通过VC发送控制消息以用作LSP来执行。上游节点分配VCID值。它通知下游节点该值的过程如下所示。创建新VC或向VC添加新叶时，将使用此过程。
First, the procedure for establishing the first VC is described.
首先，描述用于建立第一VC的过程。
1. The upstream node assigns a VCID value for the VC. When the VCID value is already assigned to a VC, it is used for VCID.
1. 上游节点为VC分配一个VCID值。当VCID值已分配给VC时，它将用于VCID。
2. The upstream node sends a message which contains the VCID value and a message ID through the VC used for an LSP. This message is transferred to all leaf nodes.
2. 上游节点通过用于LSP的VC发送包含VCID值和消息ID的消息。此消息将传输到所有叶节点。
3. The upstream node establishes an association between the outgoing label for the VC and the VCID value.
3. 上游节点在VC的传出标签和VCID值之间建立关联。
4. When the downstream nodes receiving the message already received the LDP REQUEST message for the VC, the received message is discarded. Otherwise, the downstream nodes establish an association between the VCID in the message and the VC from which the message is received.
4. 当接收消息的下游节点已经接收到针对VC的LDP请求消息时，所接收的消息被丢弃。否则，下游节点在消息中的VCID与接收消息的VC之间建立关联。
5. The downstream nodes send an ACK message to the upstream node.
5. 下游节点向上游节点发送ACK消息。
6. After the upstream node receives the ACK messages, the upstream node and the downstream nodes share the VCID. The upstream node sends the LDP REQUEST message in order to make a 3-way handshake.
6. 在上游节点接收到ACK消息之后，上游节点和下游节点共享VCID。上游节点发送LDP请求消息以进行3路握手。
Upstream Downstream 1 Downstream 2
| | |
|-----------+--->| | VCID PROPOSE
| +------------------->|
| | |
|<---------------| |
| VCID ACK | |
|<-------------------------------| VCID ACK
Upstream Downstream 1 Downstream 2
| | |
|-----------+--->| | VCID PROPOSE
| +------------------->|
| | |
|<---------------| |
| VCID ACK | |
|<-------------------------------| VCID ACK
Second, the procedure for adding a leaf to the existing point-to-multipoint VC is described.
其次，描述了将叶添加到现有点对多点VC的过程。
0. The upstream node adds the downstream node, using the ATM signaling.
0. 上游节点使用ATM信令添加下游节点。
1. The VCID value which already assigned to the VC is used.
1. 使用已分配给VC的VCID值。
2. The upstream node sends a message which contains the VCID value and a message ID through the VC used for an LSP. This message is transferred to all leaf nodes.
2. 上游节点通过用于LSP的VC发送包含VCID值和消息ID的消息。此消息将传输到所有叶节点。
3. When the downstream nodes receiving the message already received the LDP REQUEST message for the VC, the received message is discarded. Otherwise, the downstream nodes establish an association between the VCID in the message and the VC from which the message is received.
3. 当接收消息的下游节点已经接收到针对VC的LDP请求消息时，所接收的消息被丢弃。否则，下游节点在消息中的VCID与接收消息的VC之间建立关联。
4. After the upstream node receives the ACK messages, the upstream node and the downstream nodes share the VCID. The upstream node sends the LDP REQUEST message in order to make a 3-way handshake.
4. 在上游节点接收到ACK消息之后，上游节点和下游节点共享VCID。上游节点发送LDP请求消息以进行3路握手。
This method can be applied when a VC is established using an ATM signaling message and the message has a field which is not large enough to carry a VCID value.
当使用ATM信令消息建立VC，并且该消息的字段不足以承载VCID值时，可以应用此方法。
SETUP message of the ATM Forum UNI 3.1/4.0 has a 7-bit mandatory field for the user. This is a user specific field in the Layer 3 protocol field in the BLLI IE (Broadband Low Layer Information Information Element).
ATM论坛UNI 3.1/4.0的设置消息对用户有一个7位必填字段。这是BLLI IE（宽带低层信息元素）中第3层协议字段中的用户特定字段。
The BLLI value is used as a temporary identifier for a VC during a VCID notification procedure. This mechanism is defined as "Outband Notification using a small-sized field". The BLLI value of a new VC must not be assigned to other VCs during the procedure to avoid identifier conflict. When the association among the BLLI value, a
BLLI值在VCID通知过程中用作VC的临时标识符。该机制被定义为“使用小型字段的带外通知”。在此过程中，不得将新VC的BLLI值分配给其他VC，以避免标识符冲突。当BLLI值之间的关联
VCID value, and the corresponding VC is established, the BLLI value can be reused for a new VC. VCID values can be assigned independently from BLLI values.
VCID值，并建立相应的VC，BLLI值可重新用于新VC。VCID值可以独立于BLLI值进行分配。
Node A Node B
| |
|--------------->| ATM Signaling with BLLI
|<---------------|
| |
|--------------->| VCID PROPOSE with BLLI
| |
|<---------------| VCID ACK
| |
|--------------->| LDP Label Request
| |
|<---------------| LDP Label Mapping
Node A Node B
| |
|--------------->| ATM Signaling with BLLI
|<---------------|
| |
|--------------->| VCID PROPOSE with BLLI
| |
|<---------------| VCID ACK
| |
|--------------->| LDP Label Request
| |
|<---------------| LDP Label Mapping
A point-to-multipoint VC can also be established using ADD_PARTY of the ATM Forum Signaling. ADD_PARTY adds a new VC leaf to an existing VC or an existing VC tree. In this procedure, the BLLI value of ADD_PARTY has to be the same value as that used to establish the first point-to-point VC of the tree. The same BLLI value can be used in different VC trees only when these VC trees can not add a leaf at the same time. As a result, the BLLI value used in the signaling must be determined by the root node of the multicast tree.
也可以使用ATM论坛信令的添加方建立点对多点VC。添加方将新的VC叶添加到现有VC或现有VC树。在此过程中，ADD_PARTY的BLLI值必须与用于建立树的第一个点到点VC的值相同。只有当不同的VC树不能同时添加叶子时，才能在不同的VC树中使用相同的BLLI值。因此，信令中使用的BLLI值必须由多播树的根节点确定。
[note] BLLI value is unique at the sender node. But BLLI value is not unique at the receiver node because multiple sender nodes may allocate the same BLLI value. So, the receiver node must recognize BLLI value and the sender address. ATM Signaling messages (SETUP and ADD_PARTY) carry both the BLLI and the sender ATM address. The receiver node can realize which node sends the BLLI message.
[注意]BLLI值在发送方节点上是唯一的。但是BLLI值在接收方节点处不是唯一的，因为多个发送方节点可能分配相同的BLLI值。因此，接收方节点必须识别BLLI值和发送方地址。ATM信令消息（设置方和添加方）携带BLLI和发送方ATM地址。接收方节点可以实现哪个节点发送BLLI消息。
3.2.1 Outband notification using a small-sized field for point-to-point VC
3.2.1 使用小型字段进行点对点VC的带外通知
This subsection describes procedures for establishing a VC and for notification of its VCID between neighboring LSRs for unicast traffic.
本小节描述了在单播业务的相邻LSR之间建立VC和通知其VCID的过程。
The procedure employed when the upstream LSR assigns a VCID is as follows.
上游LSR分配VCID时采用的程序如下。
1. An upstream LSR establishes a VC to the downstream LSR using ATM signaling and supplies a value in the BLLI field that it is not currently using for any other (incomplete) VCID notification transaction with this peer.
1. 上游LSR使用ATM信令向下游LSR建立VC，并在BLLI字段中提供当前未用于与该对等方的任何其他（不完整）VCID通知事务的值。
2. The upstream LSR sends the VCID PROPOSE message through the VC for LDP to notify the downstream LSR of the association between the BLLI and VCID values.
2. 上游LSR通过VC for LDP发送VCID建议消息，以通知下游LSR BLLI和VCID值之间的关联。
3. The downstream LSR establishes the association between the VC with the BLLI value and the VCID and sends an ACK message to the upstream LSR.
3. 下游LSR在具有BLLI值的VC和VCID之间建立关联，并向上游LSR发送ACK消息。
4. After the upstream LSR receives the ACK message, it establishes the association between the VC and the VCID. The VC is ready to be used. At this time the BLLI value employed in this transaction is free for reuse.
4. 上游LSR收到ACK消息后，建立VC和VCID之间的关联。VC已准备好使用。此时，此事务中使用的BLLI值可以自由重用。
5. After VCID notification, the upstream node sends the LDP REQUEST message to the downstream node. The downstream node sends the LDP mapping message, which contains the VCID value in the label TLV of LDP.
5. 在VCID通知之后，上游节点向下游节点发送LDP请求消息。下游节点发送LDP映射消息，该消息包含LDP标签TLV中的VCID值。
3.2.2 Outband notification using a small-sized field for point-to-multipoint VC
3.2.2 使用小型字段的点对多点VC带外通知
This subsection describes procedures for establishing the first VC for a multicast tree and for adding a new VC leaf to an existing VC tree including the notification of its VCID for a multicast stream using point-to-multipoint VCs.
本小节描述了为多播树建立第一个VC和向现有VC树添加新VC叶的过程，包括使用点对多点VCs通知多播流的VCID。
In this procedure, an upstream LSR determines both the VCID and BLLI value in the multicast case. The reason that the BLLI value is determined by an upstream LSR is described above.
在此过程中，上游LSR确定多播情况下的VCID和BLLI值。上面描述了由上游LSR确定BLLI值的原因。
First, the procedure for establishing the first VC is described.
首先，描述用于建立第一VC的过程。
1. An upstream LSR establishes a VC by the ATM Forum Signaling between the downstream LSR with a unique BLLI value at this time.
1. 此时，上游LSR通过ATM论坛信令在具有唯一BLLI值的下游LSR之间建立VC。
2. The upstream LSR notifies the downstream LSR of a paired BLLI value and VCID using a message dedicated for this purpose.
2. 上游LSR使用专用于此目的的消息通知下游LSR成对的BLLI值和VCID。
3. The downstream LSR establishes the association between the VC with the BLLI value and the VCID and sends an ACK message to the upstream LSR. If the VCID is used by some other VC between the upstream and downstream LSRs, the old VC is discarded.
3. 下游LSR在具有BLLI值的VC和VCID之间建立关联，并向上游LSR发送ACK消息。如果VCID被上游和下游LSR之间的其他VC使用，则旧VC将被丢弃。
4. After the upstream LSR receives the ACK message, the VC is ready to be used and the BLLI value can be used for another VC.
4. 上游LSR收到ACK消息后，VC准备好使用，BLLI值可用于另一个VC。
Second, the procedure for adding a leaf to the existing point-to-multipoint VC is described.
其次，描述了将叶添加到现有点对多点VC的过程。
1. The upstream LSR establishes a VC by the ATM Forum Signaling between its downstream LSR with the BLLI value that was used during the first signaling procedure. If another VC is using the BLLI value at the same time, the upstream waits for the completion of the signaling procedure that is using this BLLI value.
1. 上游LSR通过ATM论坛信令在其下游LSR与第一信令过程中使用的BLLI值之间建立VC。如果另一个VC同时使用BLLI值，则上游等待使用该BLLI值的信令过程完成。
2. Go to step 2 of the procedure for the first VC.
2. 进入第一个VC程序的步骤2。
This method can be applied when a VC is established using a ATM signaling message and the message has a field (e.g., GIT [GIT]) which is large enough to carry a VCID value. Message format is described in [GIT]. After the VCID notification, the node A sends the LDP request message is sent to the node B. Then, the node B sends the LDP mapping message to the node A.
当使用ATM信令消息建立VC并且该消息具有足够大以携带VCID值的字段（例如GIT[GIT]）时，可以应用该方法。消息格式在[GIT]中描述。在VCID通知之后，节点A向节点B发送LDP请求消息，然后节点B向节点A发送LDP映射消息。
Node A Node B
| |
|--------------->| ATM signaling with VCID
|<---------------|
| |
|--------------->| LDP Label Request
| |
|<---------------| LDP Label Mapping
Node A Node B
| |
|--------------->| ATM signaling with VCID
|<---------------|
| |
|--------------->| LDP Label Request
| |
|<---------------| LDP Label Mapping
4 VPID Notification Procedure
4 VPID通知程序
The approach that is used for the VCID notification procedure is also applicable to share the same identifier between both ends for a VP. VPID notification procedure is defined for this purpose.
用于VCID通知过程的方法也适用于在VP的两端共享相同的标识符。VPID通知程序是为此目的而定义的。
A distinct VPID notification procedure is performed for each direction of each VP.
对每个VP的每个方向执行不同的VPID通知程序。
After the VPID notification is finished for a VP, a VCID of a VC in the VP is constructed with the VPID(MSB) and VCI(LSB) of the VC. The VCID can be used by LDP without performing VCID notification procedure. The message sequence is given below.
VP的VPID通知完成后，VP中VC的VCID将使用VC的VPID（MSB）和VCI（LSB）构造。LDP无需执行VCID通知程序即可使用VCID。下面给出了消息序列。
1. An upstream node sends the VPID PROPOSE message. In the case of bidirectional label switched VC, both the upstream and downstream nodes use VCI=33. In the case of unidirectional label switched VC, the node which has larger LDP Identifier uses VCI=33 and the other node uses VCI=34. Note that VCI=32, which is used for unlabeled packet transfer, is not used for VPID notification procedure so that the same encapsulation method can be applied for both VPID procedure and inband VCID procedure.
1. 上游节点发送VPID建议消息。在双向标签交换VC的情况下，上游和下游节点都使用VCI＝33。在单向标签交换VC的情况下，具有较大LDP标识符的节点使用VCI=33，而另一个节点使用VCI=34。请注意，用于未标记数据包传输的VCI=32不用于VPID通知过程，因此相同的封装方法可应用于VPID过程和带内VCID过程。
2. The downstream node sends the VPID ACK message.
2. 下游节点发送VPID ACK消息。
3. The upstream node sends the LDP Label Request message.
3. 上游节点发送LDP标签请求消息。
4. The downstream node sends the LDP Label Mapping message.
4. 下游节点发送LDP标签映射消息。
5 VCID Message Format
5 VCID消息格式
An LDP VCID message consists of the LDP [LDP] fixed header followed by one or more TLV. A VCID PROPOSE inband message and a VPID PROPOSE message are sent as a null encapsulation packet through a VC to be used as an LSP. There is only the label stack header before the LDP VCID PDU. A label value in the label stack entry [ENCAPS] for the VCID PROPOSE inband message and the VPID PROPOSE message are 4. Other messages are sent as TCP packets. This is the same as LDP.
LDP VCID消息由LDP[LDP]固定报头和一个或多个TLV组成。VCID建议带内消息和VPID建议消息作为空封装包通过VC发送，用作LSP。LDP VCID PDU之前只有标签堆栈头。VCID建议带内消息和VPID建议消息的标签堆栈条目[ENCAPS]中的标签值为4。其他消息作为TCP数据包发送。这与自民党一样。
The VCID message type field is as follows:
VCID消息类型字段如下所示：
VCID Propose inband Message = 0x0501 VCID Propose Message = 0x0502 VCID ACK Message = 0x0503 VCID NACK Message = 0x0504 VPID Propose inband Message = 0x0505 VPID ACK Message = 0x0506 VPID NACK Message = 0x0507
VCID建议带内消息=0x0501 VCID建议消息=0x0502 VCID确认消息=0x0503 VCID NACK消息=0x0504 VPID建议带内消息=0x0505 VPID确认消息=0x0506 VPID NACK消息=0x0507
This message is sent as a null encapsulation packet with LDP header and label stack header through a VC to be used as an LSP. The label value is 4. The reserved label value is required because the downstream node may receive this message after receiving the LDP
此消息作为空封装包发送，带有LDP头和标签堆栈头，通过VC作为LSP使用。标签值为4。需要保留标签值，因为下游节点可能在接收到LDP后接收到该消息
Label Request message in the case of point-to-multipoint VC. The downstream node must distinguish the VCID PROPOSE message from other messages and ignore the VCID PROPOSE message when the node already received the LDP Label Request message for the VC.
在点对多点VC的情况下，标记请求消息。下游节点必须将VCID建议消息与其他消息区分开来，并在节点已经收到VC的LDP标签请求消息时忽略VCID建议消息。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|VCID Inband Propose (0x0501) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|VCID Inband Propose (0x0501) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Id Four octet integer used to identify this message.
消息Id用于标识此消息的四个八位整数。
Label TLV Label TLV contains VCID value. Type of label TLV is VCID(0x0203).
标签TLV标签TLV包含VCID值。标签TLV的类型为VCID（0x0203）。
An LSR uses the VCID PROPOSE message for the VCID notification procedure of the outband notification using a small-sized field. This message is sent through the VC for the LDP.
LSR使用VCID建议消息作为使用小字段的带外通知的VCID通知过程。此消息通过VC发送给LDP。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VCID Propose (0x0502) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Temporary ID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VCID Propose (0x0502) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Temporary ID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message ID Four octet integer used to identify this message.
消息ID用于标识此消息的四个八位整数。
Label TLV Label TLV contains VCID value. Type of label TLV is VCID(0x0203).
标签TLV标签TLV包含VCID值。标签TLV的类型为VCID（0x0203）。
Temporary ID TLV The value carried in the user specific field in the layer 3 protocol field in the BLLI ID in the ATM Forum UNI 3.1/4.0 Type of label TLV is VCID temporary ID(0x0702).
临时ID TLV ATM论坛UNI 3.1/4.0标签类型TLV中BLLI ID第3层协议字段中用户特定字段中的值为VCID临时ID（0x0702）。
An LSR send the VCID ACK message when the LSR accepts the VCID PROPOSE message.
当LSR接受VCID建议消息时，LSR发送VCID确认消息。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VCID ACK (0x0503) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VCID ACK (0x0503) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message ID Four octet integer used to identify this message.
消息ID用于标识此消息的四个八位整数。
Label TLV The label TLV contains the VCID value of the received VCID PROPOSE message. Type of label TLV is VCID(0x0203).
标签TLV标签TLV包含收到的VCID建议消息的VCID值。标签TLV的类型为VCID（0x0203）。
VCID Message ID This value is the same as that of received VCID PROPOSE message.
VCID消息ID此值与收到的VCID建议消息的值相同。
An LSR send the VCID NACK message when the LSR does not accept the VCID PROPOSE message.
当LSR不接受VCID建议消息时，LSR发送VCID NACK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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VCID NACK (0x0504) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VCID NACK (0x0504) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message ID Four octet integer used to identify this message.
消息ID用于标识此消息的四个八位整数。
Label TLV The label TLV contains the VCID value of the received VCID PROPOSE message. Type of label TLV is VCID(0x0203).
标签TLV标签TLV包含收到的VCID建议消息的VCID值。标签TLV的类型为VCID（0x0203）。
VCID Message ID This value is the same as that of received VCID PROPOSE message.
VCID消息ID此值与收到的VCID建议消息的值相同。
This message is sent as a null encapsulation packet with LDP header and label stack header through a VC to be used as an LSP. The label value is 4. The downstream node must distinguish the VPID PROPOSE message from other messages and ignore the VPID PROPOSE message when the node already received the LDP Label Request message for the VC.
此消息作为空封装包发送，带有LDP头和标签堆栈头，通过VC作为LSP使用。标签值为4。下游节点必须将VPID建议消息与其他消息区分开来，并在节点已经收到VC的LDP标签请求消息时忽略VPID建议消息。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|VPID Inband Propose (0x0505) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VPID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|VPID Inband Propose (0x0505) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VPID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Id Four octet integer used to identify this message.
消息Id用于标识此消息的四个八位整数。
VPID TLV VPID TLV contains VPID value. Type of label TLV is VPID(0x0703).
VPID TLV VPID TLV包含VPID值。标签TLV的类型为VPID（0x0703）。
An LSR send the VPID ACK message when the LSR accepts the VPID PROPOSE message.
当LSR接受VPID建议消息时，LSR发送VPID ACK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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VPID ACK (0x0506) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VPID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VPID ACK (0x0506) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VPID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message ID Four octet integer used to identify this message.
消息ID用于标识此消息的四个八位整数。
VPID TLV The VPID TLV contains the VPID value of the received VPID PROPOSE message.
VPID TLV VPID TLV包含收到的VPID建议消息的VPID值。
VCID Message ID This value is the same as that of received VCID PROPOSE message.
VCID消息ID此值与收到的VCID建议消息的值相同。
An LSR send the VPID NACK message when the LSR accepts the VPID PROPOSE message.
当LSR接受VPID建议消息时，LSR发送VPID NACK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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VPID NACK (0x0507) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VPID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| VPID NACK (0x0507) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VPID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message ID Four octet integer used to identify this message.
消息ID用于标识此消息的四个八位整数。
VPID TLV The VPID TLV contains the VPID value of the received VPID PROPOSE message.
VPID TLV VPID TLV包含收到的VPID建议消息的VPID值。
VCID Message ID This value is the same as that of received VCID PROPOSE message.
VCID消息ID此值与收到的VCID建议消息的值相同。
An LSR uses VCID Label TLV to encode labels for use on the link which does not have the same data link label at both ends of a VC.
LSR使用VCID标签TLV对标签进行编码，以便在VC两端没有相同数据链路标签的链路上使用。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F|VCID Label (0x0203) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F|VCID Label (0x0203) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
VCID This is 4 byte VCID value.
这是4字节的VCID值。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F|VCID Message ID(0x0701) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F|VCID Message ID(0x0701) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
VCID Message ID This is 4 byte VCID Message ID
VCID消息ID这是4字节的VCID消息ID
An LSR uses the VCID temporary ID TLV for the VCID notification procedure of the outband notification using a small-sized field.
LSR使用VCID临时ID TLV作为使用小型字段的带外通知的VCID通知过程。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| VCID Temporary ID (0x0702)| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Temporary ID |
+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| VCID Temporary ID (0x0702)| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Temporary ID |
+-+-+-+-+-+-+-+-+
Temporary ID: The value carried in the user specific field in the layer 3 protocol field in the BLLI ID in the ATM Forum UNI 3.1/4.0
临时ID：ATM论坛UNI 3.1/4.0中BLLI ID中第3层协议字段中用户特定字段中的值
An LSR uses VPID TLV for the VPID notification procedure.
LSR将VPID TLV用于VPID通知过程。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| VPID (0x0703) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VPID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| VPID (0x0703) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VPID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
VPID This is 2 byte VPID value.
VPID这是2字节的VPID值。
Security Considerations
安全考虑
This document does not introduce new security issues other than those present in the LDP and may use the same mechanisms proposed for this technology.
除LDP中存在的安全问题外，本文件不会引入新的安全问题，并可能使用针对该技术提出的相同机制。
Acknowledgments
致谢
The authors would like to acknowledge the valuable technical comments of Yoshihiro Ohba, Shigeo Matsuzawa, Akiyoshi Mogi, Muneyoshi Suzuki, George Swallow and members of the LAST-WG of the WIDE Project.
作者要感谢大叶吉弘、松泽茂雄、大木昭吉、铃木木木义彦、乔治·斯沃诺和WIDE项目最后工作组成员的宝贵技术意见。
References
工具书类
[LDP] Andersson, L., Doolan, P., Feldman, N., Fredette, A. and B. Thomas, "LDP Specification", RFC 3036, January 2001.
[LDP]Andersson，L.，Doolan，P.，Feldman，N.，Fredette，A.和B.Thomas，“LDP规范”，RFC 3036，2001年1月。
[GIT] Suzuki, M., "The Assignment of the Information Field and Protocol Identifier in the Q.2941 Generic Identifier and Q.2957 User-to-user Signaling for the Internet Protocol", RFC 3033, January 2001.
[GIT]Suzuki，M.，“互联网协议的Q.2941通用标识符和Q.2957用户对用户信令中信息字段和协议标识符的分配”，RFC 3033，2001年1月。
[ENCAPS] Rosen, E., Viswanathan, A. and R. Callon, "MPLS Label Stack Encoding", RFC 3032, January 2001.
[ENCAPS]Rosen，E.，Viswanathan，A.和R.Callon，“MPLS标签堆栈编码”，RFC 3032，2001年1月。
Authors' Addresses
作者地址
Ken-ichi Nagami Computer & Network Development Center, Toshiba Corporation, 1, Toshiba-cho, Fuchu-shi, Tokyo, 183-8511, Japan
Ken ichi Nagami计算机与网络开发中心，东芝公司，日本东京府柱市东芝町1号，183-8511
Phone: +81-42-333-2884
EMail: ken.nagami@toshiba.co.jp
Phone: +81-42-333-2884
EMail: ken.nagami@toshiba.co.jp
Noritoshi Demizu WaterSprings.ORG 1-6-11-501, Honjo, Sumida-ku, Tokyo, 130-0004, Japan
Noritoshi Demizu WaterSprings.ORG 1-6-11-501，日本东京住田区本州，130-0004
EMail: demizu@dd.iij4u.or.jp
EMail: demizu@dd.iij4u.or.jp
Hiroshi Esaki Computer Center, University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-8658, Japan
东京大学广崎电脑中心，2-11-16 Yayoi，本笃，东京，113-865，日本
Phone: +81-3-3812-1111
EMail: hiroshi@wide.ad.jp
Phone: +81-3-3812-1111
EMail: hiroshi@wide.ad.jp
Yasuhiro Katsube Computer & Network Development Center, Toshiba Corporation, 1, Toshiba-cho, Fuchu-shi, Tokyo, 183-8511, Japan
日本东京府町市东芝町1号东芝公司安弘胜本计算机与网络开发中心，183-8511
Phone: +81-42-333-2844
EMail: yasuhiro.katsube@toshiba.co.jp
Phone: +81-42-333-2844
EMail: yasuhiro.katsube@toshiba.co.jp
Paul Doolan Ennovate Networks 60 Codman Hill Road Boxborough, MA
Paul Doolan Ennovate Networks马萨诸塞州Boxborough Codman Hill路60号
Phone: 978-263-2002 x103 EMail: pdoolan@ennovatenetworks.com
电话：978-263-2002 x103电子邮件：pdoolan@ennovatenetworks.com
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Acknowledgement
确认
Funding for the RFC Editor function is currently provided by the Internet Society.
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