1 MPLS/IP Header Compression (draft-berger-mpls-hdr-comp-00.txt) MPLS/IP Header Compression over PPP (draft-berger-mpls-hdr-comp-over-ppp-00.txt) Lou Berger LabN Consulting, LLC Jason JeffordsIntegral Access Inc. March, 2000

2 MPLS/IP Header Compression Being worked on in MPLS working group –Looking to coordinate work with AVT WG Objective: –Enable header compression for MPLS encapsulated traffic CRTP assumes no header between IP and link layer

3 MPLS/IP Header Compression: Basic Approach Start with standard IP header compression –Standards assume no headers between IP and link layer RFC IP Header Compression RFC Compressing IP/UDP/RTP Headers for Low-Speed Serial Link Add support for compression of MPLS packets –Includes support for: Arbitrary number of MPLS headers P er packet MPLS EXP field changes –End result: MPLS/IP/TECP/UDP/RTP header compression Preserves standard compression header –2 bytes –4 bytes when UDP checksums are used –+ 1 byte per EXP field change –Does not increase with more MPLS headers Defines PPP link layer support –Parallels RFC IP Header Compression over PPP

4 Known Issues Bit naming collision with draft-koren-avt-crtp-enhance-01.txt –Both define bit named “N” In different locations –N=NoEXP or N=negative cache stream –In next rev NoEXP will be called the “P-bit” Current draft doesn’t support CRTP enhancements MPLS/IP Header Compression over PPP issue: –Reuse same values as IP header compression or new values –Use of different values allows for unambiguous decoding of frames - for debugging