Subject: Measurement protocol for one-way performance metrics

From: Lijun Qian <[email-masked]>
Date: Wed, 9 Aug 2000 15:13:33 -0400 (EDT)

Hi, all, here are some explanations about our approach of measurement
protocol for one-way performance metrics presented at the IETF meeting.
A protocol which measures one-way performance metrics(loss, delay, etc.)
in REAL TIME is indispensible in many cases, for example, Traffic
Engineering.

Q: How to get one-way packet loss?

A:    The source encodes a Source Sequence Number to notify the
      destination how many probe packets have been transmitted by the
      source. The destination encodes a destination Sequence Number
      to notify the source how many probe packets have been received
      by the destination so far.

      When a probe reply packet returns, the source is able to
      estimate the one-way packet loss rate based on the two
      sequence numbers encoded in the probe reply packet. The
      detailed procedure is included in Appendix 1 in
      <draft-elwalid-icmp-ext-01.txt>. (We just submitted it to IETF, it
      should be available soon. In the mean time, you could download
      it from my homepage.)

Q: What if there is packet loss in the reverse channel?

A:
      The mechanism is fault tolerant against losses in the reverse
      channel, since the source will update one-way packet loss
      rate based on the information in the most recent reply.

Suggestions, comments are welcomed.

Lijun
********************************************************************
Lijun Qian
Department of Electrical & Computer Engineering
Rutgers University
Piscataway, NJ 08854
Phone:
      (732)445-0679(Office)
Email:[email-masked]
Web:  http://www.eden.rutgers.edu/~ljqian
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