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New Member

Backup WAN link for fallback communication

My network has 3 sites A, B and C which are interconnected with E1 pipes. Call manager will be located on the LAN side of location A.

Due to some TELCO problems, links between any of these locations go down atleast once a day. Because of this reason all the sites are interconnected so that there is always an alternate path.

We are about to implement IP telephony shortly. After the implementation when there is communication between the IP phones at location A and B and the link between them goes down which is the communication path. What happens to the call? Thanks in advance.

3 REPLIES
New Member

Re: Backup WAN link for fallback communication

If you are running a decent routing protocol (OSPF or EIGRP) calls would reroute transparently when a link failed. Depending on the routing convergence time the users would either not notice the outage, or notice a few seconds of no audio. One thing to keep in mind is Locations Call Admission Control (CAC). Locations CAC does not track topology changes so the A to C link needs to be able to carry the sum of calls that CAC would allow through to sites B and C.

New Member

Re: Backup WAN link for fallback communication

By default converging to new route would take atleast about 30 seconds, is the call held for 30 seconds without disconnection?

New Member

Re: Backup WAN link for fallback communication

30 seconds? It shouldn't do should it? EIGRP for instance already knows the next best possible route and should only take a matter of a few seconds if that to switch to the new route, OSPF should be similar.

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