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Criss-crossed PVC

Hi, I was hoping someone may have some insight into this strange issue I ran into the other day.


Router has an ATM collector (ATM2/1/0) with several sub-interfaces on it. Customer has network statically routed to ATM2/0/0.658 This interface has been assigned VPI 15 VCI 658 Unfortunatly this customers VCI somehow was changed to VCI 648, which belongs to another customer on ATM2/1/0.648 Now when I run a trace route to the trace shows the path going through ATM2/1/0.648 Keep in mind that there is no static route for pointing to ATM2/1/0.648 nor are there any other routes in the routing table for that network (other than ip route ATM2/0/0.658 which is the correct route).

Somehow traffic got re-routed to the wrong interface without using anything found in the routing table (route-cache is turned off by the way). Once the VCI was changed back to 658 The customers route went back to normal. I was wondering how the router routed traffic to another interface without an ip route statement telling it to do so. Was this due to the incorrect PVC and if so I would like to know the descion making process the router takes in regards to PVCs. Any insight would be greatly appreciated.


Re: Criss-crossed PVC

Often times complex troubleshooting issues are best addressed in an interactive session with one of our trained technical assistance engineers. While other forum users may be able to help, it’s often difficult to do so for this type of issue.

To utilize the resources at our Technical Assistance Center, please visit and to open a case with one of our TAC engineers, visit

If anyone else in the forum has some advice, please reply to this thread.

Thank you for posting.

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