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New Member

Gateway Design Question

I have the following setup in my lab:

PSTN ---> 2821 ----> 2821 ---> CallManager

The 2821 are connected on the same IP LAN.

I want to set up a H323 trunk between the 2821s. Is this possible?

Can someone give me a list of steps I need to do to set this up ie

1) add h323 trunk to callmanager

2) add h323 gateway??

3) add dial-peers to gateway

Thanks in advance


Re: Gateway Design Question

Dear Bvial

"I want to set up a H323 trunk between the 2821s. Is this possible?"

Remember that a 'Gateway' acts as a threshold between a VoIP network and another type of network. In our example this is PSTN. So, a Gateway will typically have an Ethernet interface connecting to the VoIP network and an FXO or T1 interface connecting to the PSTN.

Therefore, your H323 trunk will need to be set-up between Callmanager and the 2821 that is directly connecting to the PSTN network. Whatever is in between does not really matter afaik so long as there is IP connectivity. If the topology you have provided is like-4-like, then the 2821 next to Callmanager does not require any gateway configuration or set-up.


To add a H323 Gateway:

1) Select Gateway from the device menu

2) Click on add a new Gateway link and choose H.323 from the Gateway type menu

3) The device protocol field automatically will be set to H.225. Click Next. For the device name, enter the IP address of the router which will be acting as the Gateway <-- this is the IP address for the 2821 facing the PSTN network. You must enter the IP of the interface on this 2821 router where traffic from Callmanager will be entering into (i.e. ingress interface). Remember this is the router which connects to the PSTN cloud.

4) In the device name field use the IP address of the H.323 gateway or unique IP address

5) Assign the gateway to a device pool

6) Click insert when finished


2821 gateway router config:

2821_H323_gateway(config)# gateway

2821_H323_gateway(config)# voice class h323 lab

2821_H323_gateway(config-class)# dial-peer voice lab voip

2821_H323_gateway(config-dial-peer)# voice class h323 lab

2821_H323_gateway(config-dial-peer)# destination patter

2821_H323_gateway(config-dial-peer)# session target ipv4:

2821_H323_gateway(config-dial-peer)# dtmf-relay h245-alphanumeric

NOTE: I have used 'lab' as the tag identifier. You can use another tag/name of your choice if you wish.




New Member

Re: Gateway Design Question

Hi Ajaz,

Thanks for the reply.

The point is in this lab is to simulate an environment where the 2821 connected to the PSTN is not owned or managed by us. Rather, the 2821 connected to the PSTN is provided by a service provider and they will just give us an IP address to connect to.

So, we want to route all calls through our own 2821 which has a back-to-back connection the the PSTN 2821.


New Member

Re: Gateway Design Question

Is a IPIPGW the right option here?

I basically just want all calls to route to local 2821 and then these are trunked to the 2821 (not managed by us) and sent out on the PSTN.