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)
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Authors | Andy Malis , Paul Doolan , Alex Conta | ||
Last updated | 2013-03-02 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized 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 2001Show full document text