Desktop

First a Question: is this ISDN dial-up or is your ISDN up all of the time, and is it BRI or PRI?

In any case, ISDN or not, the next step after PING is TRACE. In Windoze, that's TRACERT. This will map out the hops between stations. For optimum results, TRACE from a wkstn/server on one LAN to a wkstn/server on the other LAN. TRACE typically returns 3 values: slowest, average, fastest.

Then you can see if the problem is across your ISDN link, or on the LANs.

You also need to look at the boxes that you're using for establishing the ISDN link. They may be taking a long time for the setup of the call, but then work normally afterward. A TRACE will show this with one very high "slowest" value across your link, compared with the average and fastest.

You should also find out what kinds of diagnostics are available on your ISDN boxes (routers?). My favourite remains SYSLOG. Most Unix/Linux boxes have SYSLOG server running already, and you can download freeware SYSLOG servers for most Windoze and Mac platforms. SYSLOG is a bear to read, but all of the details are there.

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