Dial-Peers on the router vs the CUCM Publisher

[Joshua Engels]

I have a fundamentals question regarding dial-peers.  Which takes prescedence, the dial peer in call manager or the dial peer that is setup on the voice gateway?

Example:

My call manager is located in Baton Rouge.  I have a remote site in Atlanta.  The remote Site in Atlanta is an SRST site with MPLS and 1 Pots line for 911 and local calls.

Do the dial-peers on the voice gateway (2911 Router) do anything for outbound calls as long as the connection to the Call manager is up?  I am assuming the voice gateway doesn't handle outbound unless it is in SRST mode etc.?

Thanks!

[Jaime Valencia]

Let's start by clarifying that in CUCM you do not have dial peers, you have route patterns, and your questions depends, if you're using MGCP, then the DPs won't do a thing until you go to SRST, if you're using H323, you might be using the same DPs with CUCM and with SRST.

I recommend you google MGCP and H323, or search cisco.com for a doc that discusses the differences.

You need to start by understanding the protocols, and how they work with CUCM.

[David Hailey · Accepted solution]

First, the route pattern in CUCM simply routes the call to the gateway and passes along the final called number pattern.

If your gateway is running MGCP and registered to CUCM, no dial peers on the gateway are used and whatever is sent from CUCM is passed along as the called number as CUCM controls the MGCP gateway.

If your gateway is running H323, then you need both.  CUCM routes the call to the gateway and sends along the called number pattern.  However, the H323 gateway then needs to match that pattern to a dial peer to actually route the call.  Technically, it could match a translation rule in IOS and then be passed along to a dial peer as well - point is, the H323 gateway needs routing rules for the call to go anywhere.

If you run MGCP but failover to SRST, then your gateway fails over to an H.323 configuration and the same rules apply except CUCM is removed from the picture. Digit analysis and call routing is handled solely by the SRST gateway.

Hailey

Please rate helpful posts!