Use of Label Switching on Frame Relay Networks Specification
RFC 3034
| Document | Type |
RFC - Proposed Standard
(January 2001; No errata)
Was draft-ietf-mpls-fr (mpls WG)
|
|
|---|---|---|---|
| Last updated | 2013-03-02 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 3034 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
Network Working Group A. Conta
Request for Comments: 3034 Transwitch Corporation
Category: Standards Track P. Doolan
Ennovate
A. Malis
Vivace Networks, Inc.
January 2001
Use of Label Switching on Frame Relay Networks
Specification
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
This document defines the model and generic mechanisms for
Multiprotocol Label Switching on Frame Relay networks. Furthermore,
it extends and clarifies portions of the Multiprotocol Label
Switching Architecture described in [ARCH] and the Label Distribution
Protocol (LDP) described in [LDP] relative to Frame Relay Networks.
MPLS enables the use of Frame Relay Switches as Label Switching
Routers (LSRs).
Table of Contents
1. Introduction................................................2
2. Terminology.................................................3
3. Special Characteristics of Frame Relay Switches.............4
4. Label Encapsulation.........................................5
5. Frame Relay Label Switching Processing......................6
5.1 Use of DLCIs..............................................6
5.2 Homogeneous LSPs..........................................7
5.3 Heterogeneous LSPs........................................7
5.4 Frame Relay Label Switching Loop Prevention and Control...7
5.4.1 FR-LSRs Loop Control - MPLS TTL Processing.............7
5.4.2 Performing MPLS TTL calculations.......................8
5.5 Label Processing by Ingress FR-LSRs......................12
Conta, et al. Standards Track [Page 1]
RFC 3034 Label Switching with Frame Relay January 2001
5.6 Label Processing by Core FR-LSRs.........................12
5.7 Label Processing by Egress FR-LSRs.......................13
6. Label Switching Control Component for Frame Relay.........13
6.1 Hybrid Switches (Ships in the Night) ...................14
7. Label Allocation and Maintenance Procedures ..............15
7.1 Edge LSR Behavior........................................15
7.2 Efficient use of label space-Merging FR-LSRs.............18
7.3 LDP message fields specific to Frame Relay...............19
8. Security Considerations .................................21
9. Acknowledgments .........................................21
10. References ..............................................22
11. Authors' Addresses ......................................23
12. Full Copyright Statement ................................24
1. Introduction
The Multiprotocol Label Switching Architecture is described in
[ARCH]. It is possible to use Frame Relay switches as Label
Switching Routers. Such Frame Relay switches run network layer
routing algorithms (such as OSPF, IS-IS, etc.), and their forwarding
is based on the results of these routing algorithms. No specific
Frame Relay routing is needed.
When a Frame Relay switch is used for label switching, the top
(current) label, on which forwarding decisions are based, is carried
in the DLCI field of the Frame Relay data link layer header of a
frame. Additional information carried along with the top (current)
label, but not processed by Frame Relay switching, along with other
labels, if the packet is multiply labeled, are carried in the generic
MPLS encapsulation defined in [STACK].
Frame Relay permanent virtual circuits (PVCs) could be configured to
carry label switching based traffic. The DLCIs would be used as MPLS
Labels and the Frame Relay switches would become Frame Relay Label
Switching Routers, while the MPLS traffic would be encapsulated
according to this specification, and would be forwarded based on
network layer routing information.
The keywords MUST, MUST NOT, MAY, OPTIONAL, REQUIRED, RECOMMENDED,
SHALL, SHALL NOT, SHOULD, SHOULD NOT are to be interpreted as defined
in RFC 2119.
This document is a companion document to [STACK] and [ATM].
Conta, et al. Standards Track [Page 2]
RFC 3034 Label Switching with Frame Relay January 2001
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