Multi-link ISDN?

How does one get an ISDN line to use both channels? I was told I need to get the LEC to setup multi-link at both locations. Is this correct?

Reply to
Bob Mgr
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Try this

under ISDN interface "ppp multilink"

This will bring up both channels.

Bob Mgr wrote:

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We've been using that command for years on links which have come and gone and configured by different Cisco certified professionals over the last seven years but my none of our records indicate the second B channel has ever fired up on any of the circuits we've had, and we started in 1999 with Frame, later moved a handful of sites to VPN, and later again some moved to point-to-point to support VoIP. And then recently a cisco consultant was working for me and I asked him why the second B channels never fire on my circuits, he called TAC who said we must call the LEC and ask them to config Multi-link. Maybe it was a misunderstanding but I think it worth looking into. Just wonder if anyone had ever made such a request to a LEC.


Reply to
Bob Mgr


Multilink is something that is set up on the end points of the circuits (i.e. on your routers); there is nothing that the circuit network provider (e.g. your LEC) needs to do for you to run multilink over its circuits. (Other than to make sure that the circuits between point A and B are suitably error free at your desired data rate, and that there the latency variance between these circuits is not huge.)

What is relevant to your routers successfully establishing multilink dialer connections between each other is the following:

- their configurations

- the nature of the traffic that is demanding dial sessions

The dialer load-threshold in particular is an interesting command, in that it determines how much load must be present on the existing link(s) in order for dialer to try to bring up an additional link.



Reply to
Aaron Leonard

I've been using MLPPP over ISDN for years and never gotten the LEC involved (at least for proper operation of MLPPP). In addition to load-threshold, you also need to ensure that MLPPP is configured at both ends, and if using dialer profiles, on both the dialer and the ISDN interface. MLPPP is negotiated before the called interface can determine the appropriate dialer, so by the time the dialer configuration gets read, its too late.

Good luck and have fun!

V> Bob,

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