WAN LINK flipping,what is the cause?

[ahpark78]

Hi,

Currently I have a problem which the WAN link flipping causing the netview to give false impression that the link is down although the WAN Link is up,down,up,down and can be like few seconds at once.

The question is how can I debug this ?

The ISP said that is not their 64k leased line problem as they already done a loopback to their exchange.

Need help,thanks.

ken L.

[pciaccio]

A few ways:

The Netview you have is not reacting fast enough to your carrier transitions, so that is why it shows you the link is up when actually it is down. You can enable debug on serial interface events to see the transistions. It may lead you in the right direction. Also how is this 64k lease line handled. Is it going straight into the router as 4 wire where the router is doing the DSU function or are you going into an external DSU unit and going V.35 into the router?? You may need to look at the external DSU. Also you can create a loopback plug on the 4-wire line side (pins 12, 78 loopedback onto themselves). This way you can see if your local wiring and equipment are working fine.Or you can loop the circuit to the carrier to test the remote side. Possibly the issue is that the remote device is faulty...Just some ideas to try..Good Luck...