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

concurrent connection in ISDN

In ISDN, will the concurrent connections are limited to the number of B channel we have? Since it can call and maintain one connection at a time for each B channel, what if all of the interfaces are busy and some host want to dial out to another destination? Will the router buffer those interesting packets and dial out when an interface available? Or just drop them? So in ISDN BRI rate which has only 2 B channels can support only 2 destinations at a time? Can I make connections to many destinations using only1 B channel? Ex. use sub interface or multilink like Frame Relay?


Re: concurrent connection in ISDN


At any point of time with a single isdn line you can have 2 concurrent connections using the B-Channels available with the line.

The 2 connections may be both dial outs or dial ins or a mix of both.


New Member

Re: concurrent connection in ISDN

1. When both B channels are in use, subsequent dial requests to another destination will be dropped.

2. Yes, 2 B-channels can only support up to 2 destinations at one point in time.

3. No, you can't create subinterfaces on ISDN interfaces.

CreatePlease login to create content