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Cisco 801 ISDN problem...???

We have recently installed an 801 ISDN router.....using the Fast Start utility to configure.....we have 3 PC's and the router on a small LAN, the router is set-up to connect to an ISP and provide Internet access for the PC's.....we can start IE on the PC's and connect to various sites with no problems, after approx. 2 minutes the IE "sessions" begin getting the "Unable to connect to site etc..." msg.....if we wait for a few minutes the sessions appear to restart....???? During this time we are unable to ping across the ISDN.....both the LAN and ISDN Channel lights remain lit and occasionally the RX and TX lights on both light to indicate some sort of activity......???? Any ideas.....????

Community Member

Re: Cisco 801 ISDN problem...???

Try debugging the isdn (debug isdn q931 and/or debug isdn q921) to see if something is happening to the isdn link.

I think that you are facing a link up-link down maybe due to inactivity on the isdn link. I suppose you have configured an acl that "tells" your router when to trigger the isdn connection. If you browse the internet, you will trigger the isdn connection but if you don't "generate" any traffic during some period (timeout), the link will go down and will go up when you "generate" any interesting traffic again. I think that this period is that you refered as "During this time we are unable to ping across the ISDN....." and "if we wait for a few minutes the sessions appear to restart", just because the isdn connection is again established.



Community Member

Re: Cisco 801 ISDN problem...???

Wouldn't "ping" generate traffic across the ISDN and re-establish the link....???? The link-timeout is set to 300....??? The link appears to go down in the middle of browsing.....???

Because we use the fast start config utility we haven't really changed any of the router settings....can you detail how I look at an "acl"....???? This is all new to me....!!!!

Thanks for your time and patience........

Cisco Employee

Re: Cisco 801 ISDN problem...???

Ping should bringup the line if its defined interesting..Pl. post the running config so that we can verify the proper config of interesting traffic along with the idle-timeout..

"debug dialer" along with "debug isdn q931" will report any possible timeout problems..

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