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New Member

MGCP 3725 won't register with CCM 4.1?

Hi!

Our 3725 gateway is refusing to setup a MGCP backhaul connection to our CallManagers - a debug ccm-manager shows this:

18:30:37: cmbh_init_link_record: Allocated link record with address 64AB3798 for

172.16.96.1.

18:30:37: cmbh_open_tcp_link: Using MGCP bound IP addr 172.16.93.254

18:30:37: cmbh_open_tcp_link: Opening TCP link with Rem IP 172.16.96.1, Local IP

172.16.93.254, port 2428

18:30:37: cmbh_open_tcp_link: TCP Active open failed for 172.16.96.1. openstat =

17

18:30:37: cmbh_remove_link: Freeing link record with address 64AB3798 for 172.16

.96.1.

18:30:37: cmbh_init_link_record: Allocated link record with address 64B8AE70 for

172.16.96.2.

18:30:37: cmbh_open_tcp_link: Using MGCP bound IP addr 172.16.93.254

18:30:37: cmbh_open_tcp_link: Opening TCP link with Rem IP 172.16.96.2, Local IP

172.16.93.254, port 2428

18:30:37: cmbh_open_tcp_link: TCP Active open failed for 172.16.96.2. openstat =

17

18:30:37: cmbh_remove_link: Freeing link record with address 64B8AE70 for 172.16

.96.2.

The WAN connection that connects the GW to the CCMs is a 2MB leased circuit and is free of access lists. I can ping fine from end to end. If I portscan from the GW subnet to the CCMs, TCP 2428 reports as alive. Attached is a sh ccm-manager, sh mgcp and sh mgcp end.

Before I post the config, has anybody seen this issue before? It appears that the gateway thinks the CCMs are dead even though they are not!

Thanks!

Oli

3 REPLIES

Re: MGCP 3725 won't register with CCM 4.1?

Are the MGCP packets being sourced from the proper interface/address? It looks like it is currently 172.16.93.254. Are you using the "mgcp bind control" and "mgcp bind media" commands to designate this?

Brandon

Cisco Employee

Re: MGCP 3725 won't register with CCM 4.1?

Looks like the CCM is not accepting the TCP connection from the GW: "TCP Active open failed". Whether the CCM is sending a TCP RST or if the GW is not receiveing the SYN ACK from CCM is hard to determine from the debug.

As Brandon stated, make sure 172.16.93.254 is the correct address and that CCM can ping it. Is there some sort of firewll between them?

Maybe take a look at a packet capture to see the TCP communications. You should see a TCP three way handshake between the GW and CCM.

Post the config if you would like.

Make sure the Domain Name in the CCMAdmin GW config page is this: wh-mgcp-vgw

Is this a new install or one that has worked and now failed?

Kevin

New Member

Re: MGCP 3725 won't register with CCM 4.1?

Thanks for the replies! I'm using both the mgcp bind commands mentioned above and 172.16.93.254 is the correct address. The Pub and Sub can ping this address and the gateway is actually showing as registered in the gateway configuration screen. There is no firewall anywhere between the CCMs and GW - there are a number of routers but the connection is clear.

This is a new install. I'll run a packet capture and post up the config tomorrow.

Thanks, Oli.

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