Subject: 1.1 MAC "proof of performance"

From: Jason Schnitzer <[email-masked]>
Date: Thu, 25 Nov 1999 09:04:18 -0700

Folks,

I understand that there was some discussion during the last IETF/IPCDN WG
meeting on measurement metrics for MAC layer performance.

RFC-2070 provides mechanisms reporting failed transmission request in the
CM(docsifCmServiceTable) and broken requests counted over an entire MAC
domain in the CMTS (docsifCmtsStatusTable). Though it's possible to glean
some sense of performance, it's far from complete.

Has anyone proposed a mechanism for observing per SF temporal statistics?
For example, min/avg/max frame latency as seen by the CMTS. Perhaps a
layer-2 intrusive "ping" to be enabled on a per CM basis with a running
average reported via SNMP in a new CMTS table.

The operational importance of such a mechanism can't be overstated. As we
all know, CM subscriber appetites are quickly evolving from "minimize packet
loss" to "minimize packet loss, delay, and jitter". A facility providing the
visibility to help demonstrate per CM subscriber QoS SLA's would not only
support proactive management practices, but would also help appease
subscribers with rigid service requirements. 

The only mechanism currently available is ICMP -- too high up the stack and
not repeatable (downright cheesy). We need something more precise on layer 2
with per CM/SF granularity.   

Any thoughts?

Cheers,
Jason

---

From: "David Willming" <[email-masked]>
Date: Mon, 29 Nov 1999 08:56:09 -0600

Some of this capability is already supported with the Layer 2 TEST/XID
messaging.  This is like a Layer 2 PING.

     Dave

[email-masked] on 11/26/99 07:20:31 AM

Sent by:  [email-masked]

To:   "Jason Schnitzer" <[email-masked]>, [email-masked]
cc:   "'docsis-oss'" <[email-masked]>, "'docsis-macup'"
      <[email-masked]> (David Willming/MW/US/3Com)
Subject:  RE: 1.1 MAC "proof of performance"

I agree with Jason, I would definitely like to measure latency accurately on
the hfc plant and the rest of the network for that matter.  Right now we are
doing ICMP stuff with friendly modems, but I don't think its a viable
solution.  Its also useful to be able to trend latency as this is one of the
critical parameters needed for feedback into capacity planning models. - Dan
Rice

> -----Original Message-----
> From: [email-masked]
> [mailto:[email-masked]]On Behalf Of Jason Schnitzer
> Sent: Thursday, November 25, 1999 11:04 AM
> To: [email-masked]'
> Cc: 'docsis-oss'; 'docsis-macup'
> Subject: 1.1 MAC "proof of performance"
>
>
> Folks,
>