204.17.16.0/20 Unreachable via Comcast ASN 7992; Looking for Help or Contacts

Tony Tauber ttauber at 1-4-5.net
Thu Aug 8 16:39:44 UTC 2013


It's a fair question and had nothing to do with the other network (TW
Telecom, in this case, not TIme Warner Cable).
Sorry for not filling in details sooner.

We recently needed to adjust the scale profile on some of our Cisco ASR9k
trident chip (80gig) Line Cards as we reached . The default profile only
supports up to 512k routes and will notify that CEF has run out of
DATA_TYPE_TABLE_SET space as a result. The profile change required (profile
13) requires a reload of the chassis. please be advised.  You might want to
review with your local support team.

The symptom involved BGP neighbor instability and unreachability of some
destinations.
Shutting down that particular BGP session was a temporary work-around until
the adjustment could be made during a demand maintenance window to minimize
disruption.

Thanks,
Tony


On Wed, Aug 7, 2013 at 5:31 PM, Phil Fagan <philfagan at gmail.com> wrote:

> BGP Noob question here; but wouldn't Time Warner not recieve a prefix if it
> wasn't reachable? Is this an artifact?
>
>
> On Mon, Aug 5, 2013 at 11:32 AM, Chad Reid <Chad.Reid at apollogrp.edu>
> wrote:
>
> > Thanks for the assistance everyone. This issue was resolved by shutting
> > down a BGP peering session between Time Warner and Comcast. --Chad
> >
> > Chad M. Reid, Network Administrator II
> > Work Hours: Sun. - Tue. 6AM-6PM and  Wed. 6AM-3PM (MST -7)
> > Apollo Group | IT Services │ IT Operations Center (ITOC)
> > 4025 S. Riverpoint Parkway │ MS: AA-M002 │ Phoenix, AZ 85040
> > phone: 602.557.6746 │ fax: 602.557.6606 │ email: chad.reid at apollogrp.edu
> >
> >
> > -----Original Message-----
> > From: Chad Reid
> > Sent: Sunday, August 04, 2013 7:41 AM
> > To: 'nanog at nanog.org'
> > Subject: 204.17.16.0/20 Unreachable via Comcast ASN 7992; Looking for
> > Help or Contacts
> >
> > Hello NANOG,
> >
> > A few hundred of our users that use Comcast in the South East United
> > States (other regions aren't affected) are unable to access our websites
> in
> > the IP block 204.17.16.0/20. Based upon testing with the users, they're
> > getting a destination unreachable from a Comcast backbone router in ASN
> > 7922:
> > be-16-pe03.56marietta.ga.ibone.comcast.net [68.86.83.134] reports:
> > Destination net unreachable.
> >
> > We're not a customer of Comcast, nor are any of our ISPs. Because of
> this,
> > we can't find anyone at Comcast to look at this issue nor do we have good
> > contact info to even reach someone. Our users in the South East can open
> > tickets with Comcast technical support, but you can imagine how
> successful
> > they are trying to explain this to frontline support and getting
> frontline
> > support to understand.
> >
> > Is anyone from Comcast on the list that can assist or know of a contact?
> >
> >
> > Chad M. Reid, Network Administrator II
> > Work Hours: Sun. - Tue. 6AM-6PM and  Wed. 6AM-3PM (MST -7) Apollo Group |
> > IT Services │ IT Operations Center (ITOC)
> > 4025 S. Riverpoint Parkway │ MS: AA-M002 │ Phoenix, AZ 85040
> > phone: 602.557.6746 │ fax: 602.557.6606 │ email: chad.reid at apollogrp.edu
> >
> >
> >
> > This message is private and confidential. If you have received it in
> > error, please notify the sender and remove it from your system.
> >
> >
> >
> >
>
>
> --
> Phil Fagan
> Denver, CO
> 970-480-7618
>


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