The MPLS WG Archive

[David Zelig <Davidz@corrigent.com>]

Tom, Dave and Jim,

In order to detect payload defects at the STS level there are BIP checking
on the path overhead. If an operator want to check errors generated by the
CEM operation it may be simpler (and more understood) to monitor the B3 byte
for errors in both ends of the tunnel. This can be done on the example below
on the interface on the IP edge device.

It is very hard to manipulate CEM errors to payload errors, and if the
customer bought SONET service (and sign on SONET SLA) the PM should be on
SONET "language" and measured at the SONET level.

Sure we must cover all potential CEM errors in order to enable detecting the
cause of the errors, especially for the case of problems caused by
mis-configuration.I think that we need to deliver interval data for all PM
related errors, and for events count.

David
-----Original Message-----
From: Thomas D. Nadeau [mailto:tnadeau@cisco.com]
Sent: Wednesday, February 28, 2001 5:49 AM
To: Dave Danenberg; Jim Boyle
Cc: mpls@UU.NET
Subject: RE: draft-danenberg-sonet-ces-mpls-mib-00.txt


At 08:02 PM 2/27/2001 -0500, Dave Danenberg wrote:
>Jim,
>
>Thanx for your input. It sounds like you'd like to see the same sort of
>statistical information from the emulated SONET that folks are
>accustomed to seeing from SONET networking equipment. I like that too
>(from years of developing telecomm equipment for service providers).
>
>Although I was considering second order counts (errored seconds) or
>trends (15 minute, 24 hour interval data), I decided to start with just
>simple counts - and see what folks think.
>
>Andy's CEM does not detect errors over the CEM payload, but it does
>detect errors within the CEM header (the CEM MIB counts them with
>mplsCemVcPerfCrctHdrErrors and mplsCemVcPerfUncrctHdrErrors). Perhaps
>CEM header error rates can be extrapolated to indicate payload errors
>rates. Due to the nature of CEM, other types of errors are detectable
>(buffer errors, missing packets, etc). Assuming CEM equipment can
>process this raw info into some nice statistics, another set of objects
>can be added to the CEM MIB.
>
>So, I'd like to include the type of statistical info you suggest as well
>as your "reason for last down" idea. Would you like to see interval data
>as well?
>
>What do you think Tom? If you agree, I can come up with another set of
>objects and send it to Jim (and mpls email) for comment.

         Yes, as I mentioned earlier, I think these things are a
good idea. Lets work on them and get our ideas back out to the
list shortly.

         --Tom




>Dave
>
>
>-----Original Message-----
>From: owner-mpls@UU.NET [mailto:owner-mpls@UU.NET]On Behalf Of Jim Boyle
>Sent: Tuesday, February 27, 2001 2:24 PM
>To: Thomas D. Nadeau
>Cc: mpls@UU.NET
>Subject: Re: draft-danenberg-sonet-ces-mpls-mib-00.txt
>
>
>
>pretend you are a service provider, a customer calls in and says he's
>seeing errors on his service (in particular, bip violalations in POH).
>
>He is directly connected to your network via port A.
>On the far end, he connects to a clec, which hands it off to you at port
>Z.  He connects to a CLEC adm on port Z'.  His path terminating
>equipment
>(maybe a router) is port Ac, and Zc, such that the service looks like:
>
>Ac-A-[IP]-Z-CLEC-Z'-Zc
>
>Looking at lines Ac-A and Z-CLEC shows clean lines.
>
>How does the operator determine if his IP network is to blame, or the
>CLECs network is to blame?
>
>i'd recomend a few things:
>
>o) Andy's draft should have some sort of way to determine if there are
>bit
>errors hapenning across the IP network that affect the service
>payload.  This would provide the same sort of delineation of where a
>problem is occuring by looking at LOHs in more traditional transport
>network.
>
>o) your mib should include analogues to the SONET mib, such as bip-8
>violations, errored seconds, etc... (working off memory here).
>
>o) addition of a "reason for last down" might be nice.
>
>This way, when you, as the service provider, replies that "it's not our
>problem, must be the clec", they can say at least go look at it later to
>see if they were telling the truth.
>
>As usual, excellent attention paid to the configuration aspects.
>
>regards,
>
>Jim
>
>
>On Fri, 23 Feb 2001, Thomas D. Nadeau wrote:
>
> >
> >       Hi,
> >
> >       FYI a new MIB for managing SONET/SDH Circuit Emulation
> > Service Over MPLS has been posted. It should be available
> > shortly via the IETF's web site. In the meantime, it is available
> > at the following web/ftp link. As usual, comments are welcome.
> >
> >
>ftp://anonymous@ftp-eng.cisco.com/ftp/tnadeau/draft-danenberg-sonet-ces-
>mpls-mib-00.txt
> >
> >       --Tom
> >