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VCID Notification over ATM link for LDP (RFC3038)

IP.com Disclosure Number: IPCOM000005230D
Original Publication Date: 2001-Jan-01
Included in the Prior Art Database: 2001-Aug-17
Document File: 20 page(s) / 39K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

K. Nagami: AUTHOR [+5]

Abstract

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.

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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

Status of this Memo

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.

Copyright Notice

Copyright (C) The Internet Society (2001). All Rights Reserved.

Abstract

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.

1. Introduction

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.

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.

Nagami, et al. Standards Track [Page 1]

RFC 3038 VCID Notification for LDP January 2001

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 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.

2. Overview of VCID Notification Procedures

2.1 VCID Notification procedures

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 swit...