Subject: Re: [ippm] bandwidth measuring/estimating

From: "Allen B. Downey" <[email-masked]>
Date: Fri, 22 Jun 2001 10:30:46 -0400 (EDT)

On Thu, 21 Jun 2001, [email-masked] wrote:

> 1.  The premise of this thread if I remember correctly was a statement made
> wrt "I'm surprised more people are not interested in validating what their
> b/w is from their provider."  In that case where Joe pays for a 40Mb/s
> pipe to his provider and Joe wants to check that her provider really gives
> her the b/w she cares to pay for the test is really only hurting Joe if
> Joe decides to saturate a link for a long period of time.
> If Joe targets the provider's router though Joe is likely to have some
> very upset provider at the other end of the phone.  Routers are not good
> targets for such tools as they should be routing not measuring.

This scenario is something pathchar/pchar/clink are useful for.
Since the link in question is likely to be close to the sender,
and not as fast as backbone links, you are likely to get an
accurate answer.  Also, the route to that link is unlikely to
change, so you could spread the measurement over an arbitrarily
long period of time, and thereby make the measurement load
insignificant.  The only caveat is that the number you get
would be the hardware bandwidth of the link -- it would not
tell you what fraction of that bandwidth a given customer could
get.

In general, pathchar/pchar/clink are configured to introduce
an insignificant amount of traffic.

Cheers,
Allen

_______________________________________________
ippm mailing list
[email-masked]
http://mailhost.advanced.org/mailman/listinfo/ippm

---

From: Victor Reijs <[email-masked]>
Date: Thu, 28 Jun 2001 10:28:17 +0100

Hello all of you,

> > Joe decides to saturate a link for a long period of time.

Can the pchar/pathrate/clink family determine the physical capacity or
can they also determine the logical capacity (like determined the
bandwidth determined by shaping/CAR etc. IP features in a router)?

I really wonder of they are able to do this? (they even can't determine
if a link is OC-3c, because it only measures an OC-1).

If these tools can't see these 'IP features', they are perhaps not
really usefull. Hope someone can help me with this 'IP feature' issue
and the tools.

All the best,

Victor