5. Tony Dongliang Feng (tdfeng@sfu.ca)

Implementing MTU Signalling Extensions for LDP In OPNET:

Project Description:

1. Introduction

Multiprotocol Label Switching-MPLS has now become a fundamentally important technology in the internet. Several of the largest Internet service providers have deployed MPLS in their production networks to solve problems such as traffic engineering and to offer IP services efficiently over ATM backbone networks. [5]

As currently specified in RFC 3036 [3], the LDP protocol for MPLS does not support signalling of the MTU for LSPs to ingress LSRs. This functionality is essential to the proper functioning of RFC 1191 [2]. Without knowledge of the MTU for an LSP, edge LSRs may transmit packets along that LSP which are, according to [4], too big. Such packets may be silently discarded by LSRs along the LSP, effectively preventing communication between certain end hosts. [1]

The solution proposed in [1] enables automatic determination of the MTU for an LSP with the addition of a TLV to carry MTU information for a FEC between adjacent LSRs in LDP Label Mapping messages.

2. Project plan

In this project, I will first try to implement MTU Signalling extension for LDP [1] in OPNET. Then I will compare the model of extension with the one from the OPNET MPLS model suite .

Reference:

[1] Black et al,"MTU Signalling Extension for LDP" (draft-black-ldp-mtu- extension-02), Noverber 2001.

[2] Mogul, J. and S, Deering, "Path MTU Discovery",RFC 1191, November 1990.

[3] Andersson et al, "LDP Specification", RFC 3036, January 2001.

[4] Rosen et al, " MPLS Label Stack Encoding", RFC 3032, January 2001.

[5] Bruce Davie and Yakov Rekhter, MPLS Technology and Applications, Morgan Kaufmann Publishers, 2000