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Occasional unreachability on switched metro ethernet connection

spfister336
Level 2
Level 2

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?

1 Reply 1

Leo Laohoo
Hall of Fame
Hall of Fame
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.

You need to provide output to the interface (of both sides) during normal and abnormal operations.

Outputs such as "sh logs" and "sh interface " are very helpful.

AT&T is not considering this to be a problem on their equipment.

This is a "normal" behaviour of any Telco.  "Innocent until proven guilty".  If this link has a good or very good SLA agreement with AT&T, then consider getting an BER (Bit Error Rate) Test done.  Preferrably >4 hours.

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