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E2E VoIP over MPLS ('VoMPLS') Header Compression

  • From: "Ash, Gerald R (Jerry), ALABS" <gash@att.com>
  • Date: Wed, 19 Feb 2003 10:29:06 -0500
  • Cc: "Ash, Gerald R (Jerry), ALABS" <gash@att.com>, "raymond zhang" <zhangr@info.net>, "MPLS@UU.net" <MPLS@UU.NET>, "George Swallow" <swallow@cisco.com>, "Loa Andersson" <loa.andersson@utfors.se>, "GOODE, B (Bur), ALABS" <bgoode@att.com>, "Hand, James C, ALABS" <jameshand@att.com>, "Dave Cooper" <cooper@GBLX.net>
  • Thread-Index: AcLX0nC9C2v8Rxd4TDuCeRrgnh/KvAAVNQvQ
  • Thread-Topic: E2E VoIP over MPLS ('VoMPLS') Header Compression
  • X-MIME-Autoconverted: from quoted-printable to 8bit by cell.onecall.net id h1JFQUP28405

Curtis,

>I think the SPs should speak as to whether the bandwidth inefficiency
>of 30 byte payloads or the potential to lose a packet with a 200 byte
>is a greater problem.  

Both are important issues, but if you read the first few sentences of http://ietf.org/internet-drafts/draft-ash-e2e-vompls-hdr-compress-00.txt you'll see that bandwidth efficiency plays a major role in the motivation for the proposed capability.  Further, the packet sizes quoted in the I-D are typical for VoIP in SP networks, as Raymond noted.  Also, VoIP header compression (cRTP, for example) is in use in SP networks on a link by link basis to address the bandwidth efficiency issue.  

The proposal in the I-Ds is to extend VoIP header compression on an end-to-end basis, in an MPLS context.

Your suggestions for muxing voice calls into larger packets connote a PSTN/TDM-like model.  Some people actually think that the TDM model is pretty efficient for voice, however, VoIP is another matter, and has issues for larger packets, e.g., increased e2e delay, etc.

Jerry