Subject: Re: Latency and load

From: David Newman <[email-masked]>
Date: Mon, 23 Aug 1999 17:20:07 -0400

What Jim said.

The particular instances I mentioned always involved more than two
ports, but I don't think that should be a requirement in determining a
"correct" method of measurement. The methodology should work independent
of the number of ports. Of course, the number of ports, offered load,
and traffic orientation should be declared by the tester.

dn

> I think the current discussion is about what might be the ingredients of
> "correct way" since there is no specific definition in 1944/2544 about
> multiport devices.  Multiport devices probably have different latency
> characteristics for different paths but that is a real rathole!!
> 
> Jim McQuaid
> Ganymede Software
> 
> -----Original Message-----
> From: [email-masked]
> [mailto:[email-masked]]
> Sent: Monday, August 23, 1999 1:31 PM
> To: [email-masked]
> Subject: Latency and load
> 
> 
> I have another question regarding the Latency and Load issue.
> 
> How many port pairs are you utilizing when running the latency test  ??

---

From: Jeffrey Dunn <[email-masked]>
Date: Mon, 23 Aug 1999 22:06:09 -0400

David,

I absolutely disagree.  In the case of devices such as ATM and FR
switches or routers, the number of cells/frames/packets per second per
port/interface and, more importantly, the number of forwarding
discussions per port/interface per second will significantly effect both
the latency and loss statistics.  In any device which bases forwarding
decisions on information in multi-level caches, the number of ports and
destinations per port involved in a test will drastically impact
performance both in latency and loss.

Jeff Dunn
Advanced Network Consultants

>David Newman wrote: