Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Problem with concurrent ISDN2 into ISDN30

I have 4 remote sites with an ISDN2 circuit defined as a backup interface to the serial link. The ISDN2 dials into the central routers ISDN30 interface. If I test each of these 4 sites INDIVIDUALLY by pulling the serial link, they establish a dial-up connection with the central router, I see the (OSPF) routing table update and traffic successfully routed over this dialup connection. If I test this SIMULTANEOUSLY I see all sites dial and make a connection at about the same time (from doing show ISDN active). However, I only see 1 site change in the routing table of the central router. I think it may be the 1st site to have established the dial-up connection, but I'm not 100%. It looks like the other sites remain connected, but no traffic routes to these sites as the routing table is not updated, they then disconnect as the timer has expired rather than being kept alive by active traffic.

All routers work dialling into central router with only 1 at a time and they are all part of the OSPF area.

It is worth noting that the serial links are terminated on one central router, the dialup links are terminated on another router.

Any ideas ?


Re: Problem with concurrent ISDN2 into ISDN30


can you post the dial and ospf config of your "ISDN30" gateway please? Otherwise it is hard to tell why things go wrong. In priciple this should work.

Regards, Martin

CreatePlease login to create content