mgcp voice gateway reachable by ip address instead of domain name?

[baselzind]

is it possible instead of using a domain name to reach the voice gateway in the cucm like gw.mydomain.com to use an ip address? as in to write an ip address in the "domain name" bracket?

[Jitender Bhandari · Accepted solution]

Hi

Looks like you cant.

Domain Name

Enter a name of up to 64 characters that identifies the Cisco MGCP gateway. Use the Domain Name Service (DNS) host name if it is configured to resolve correctly; otherwise, use the host name as defined on the Cisco MGCP gateway. If you are using the host name as it is configured on the IOS gateway, the name that you enter here must match exactly. For example, if the hostname is configured on the gateway to resolve to vg200-1 and the IP domain name is not configured, enter the hostname in this field (in this case, vg200-1). If the hostname is configured on the gateway as vg200-1 and the IP domain name is configured on the gateway as cisco.com, enter vg200-1.cisco.com in this field.

JB

[baselzind]

so for my 2911 analog voice gateway i need to create a DNS A-record like AG3 that point to an ip in my local network DNS?

[Manish Gogna · Accepted solution]

Hi,

The "MGCP Domain Name" of a gateway is similar in function to the device name used to identify a phone ( based on the phone's MAC address ). In this way, the MGCP Domain Name of a gateway need not be accessible by DNS in any fashion. Rather, the MGCP Domain Name being used by the gateway device only needs to match the MGCP Domain Name that is configured for this same device in the CallManager configuration.

So, you don't need any DNS config for this to work.

Just make sure that you add the same domian name on cucm which you get from the output of "show ccm-manager" on gateway.

HTH

Manish

[baselzind]

so how does the cucm figure out how to reach the gateway if there is no mac address or ip address inserted? even the device name isnt linked to a dns A-record?

[Manish Gogna]

The PRI's or FXO ports on gateway register to CUCM as MGCP is a Master Slave protocol, so these endpoints ( PRI and FXO ) are controlled by CUCM. The mgcp config on gateways requires you to mention the cucm ip address and that's how they download the config file from cucm.

Manish

[baselzind]

so basically cucm knows about the mgcp gateway when the gateway communicate with it , the cucm then resgister it's ip address

[Jitender Bhandari]

Both CUCM and GW has MGCP stack on them once the IP connection is established the MGCP stack on both devices would establish a connection and that's what explained in the link above.

JB

[Jitender Bhandari]

Hey,

Just curious if your mgcp setup is working now.

JB

[baselzind]

yes i didn't add a dns record and it is working now , the gw can see cucm and vice versa.

[Jitender Bhandari]

thanks for updating the post.

[Manish Gogna]

Important thing to note is that the gateway itself is not registered, its the endpoints in the gateway ( PRI/FXO ) that get registered, so when you go to cucm and try to add them to a route group/list they appear as separate PRI/FXO ports rather than the MGCP gateway.

Manish

[Jitender Bhandari]

Rightly said by Manish, its all IP till the time it hits the gateway and gateway changes it to either analog or ISDN on the pstn end. See below for 

Understanding MGCP Interactions with Cisco CallManager

http://www.cisco.com/c/en/us/support/docs/voice/media-gateway-control-protocol-mgcp/44130-understanding-mgcp.html

JB