Subject: Re: invalid values for intserv parameters?

From: [email-masked]
Date: Wed, 2 Apr 97 14:49:04 PST

JJ,

The ISI implementation sets the defaults:

	p = floating pt infinity
	m = 0
	M = 65535

in a Tspec.  These values seems sensible to me.

Bob Braden

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From: John Krawczyk <[email-masked]>
Date: Wed, 2 Apr 1997 17:59:21 -0500

On Wed, 2 April, [email-masked] ([email-masked]) wrote:

   	p = floating pt infinity
   	m = 0
   	M = 65535

p seems fine, but let's look at the other two.

m says "I'm going to send zero-length packets"   ???

This doesn't allow a router to figure out how much bandwidth to reserve
for the link-level headers that have to be appended to your zero-length
packets.

With M of 65535, you will not successfully install a reservation over
any link with an MTU of lesser value.

Since sending my message, I finally did find some rules about these
parameters in draft-ietf-intserv-charac-02.txt:

   The peak traffic rate p is measured in bytes of IP datagrams per
   second. Values of this parameter may range from 1 byte per second to
   40 terabytes per second.

That needs to be updated to include the infinity value (to be consistant
with rsvp-use).

   The minimum policed unit, m, is an integer measured in bytes.  All IP
   datagrams less than size m will be counted against the token bucket
   as being of size m. The maximum packet size, M, is the biggest packet
   that will conform to the traffic specification; it is also measured
   in bytes.  Both m and M must be positive, and m must be less then or
   equal to M.

-jj