[c-nsp] Occasion unreachability on switched metro ethernet connection

[Steven Pfister]

We have several remote sites connecting back to a central site through
AT&T's switched metro ethernet service, CSME. We have several CSME
connections at the central side, each providing 100 Mbps bandwidth to
about 10 sites each.

Recently, they're having us convert over to a new service, Opt-E-Man.
Since, some of the central site connections were not set up correctly in
the beginning, the existing central side connections are needing to have
the sites they serve moved elsewhere temporarily so they can be
reconfigured. This process is underway, but we're running into a
problem. Two of the sites which were moved temporarily and have been
moved back are losing connectivity for periods of time (these sites are
now Opt-E-Man sites). They come and go seemly randomly. As far as I can
see,  nothing is being changed on either side. 

When the sites become unreachable from the central side (pings are
failing), I can still connect to other sites served by the same central
side connection and get to the "unreachable" site. Once on the
"unreachable" site, everything looks fine. The default gateway is set
correctly (but can't be pinged), the results of 'show ip eigrp
neighbors' seems fine. And then suddenly, without changing anything,
that site will return to normal. AT&T is not considering this to be a
problem on their equipment. The configuration on our equipment is
basically exactly the same as it's always been. Two sites have problems,
and others have no problems at all.
Is there some way I can prove it is AT&T's problem or if it is on our
end?





Steve Pfister
Technical Coordinator, 
The Office of Information Technology
Dayton Public Schools
115 S. Ludlow St. 
Dayton, OH 45402

Office (937) 542-3149
Cell (937) 673-6779
Direct Connect: 137*131747*8
Email spfister at dps.k12.oh.us