gatekeeper and gateway

[shouyisun]

Can we use gateway also as a gatekeeper? what's the modle Cisco normally recommended?

Thanks

[litrenta]

gateway and gatekeeper can co-exist but watch your CPU usage. The model depends on the traffic. IF its pretty busy you would probably look at a 3745 or 5400HPX

[shouyisun]

Thanks. I have another question also with respect to gatekeeper. Since gateway sends the call request to gatekeeper, what is the role CCM involved here in terms of talking with gatekeeper?

[litrenta]

You add the gatekeepr as a device in call manager, if you want to allow calls to come in from this gatekeeper then you check allow anonymous calls. You can set a tech prefix to register with in this screen as well. CCM will register to the gatekeeper as a gateway and you set the gatekeeper to route calls via tech or zone prefix accordingly. Then when a call comes into gateway:

gateway ______gk _________ccm

ARQ---------------<

<------------------ACF

setup----------------------------------->

<------------------ARQ

ACF---------------->

<----------------------------------call proceeding

<----------------------------------alerting

<-----------------------------------connect

connect ack----------------------------->

<------------------------------------------------rtp stream-------------------------->ip phone

of course in the background there is skinny messaging between CCM and ip phone and H.245 negotiation between gateway and CCM.

We show gatekeeper as a separate entity even though it can reside on the same box.

[eyabane]

I believe the CCM, when configured properly, will process the call admission control on behalf of the GW. in other words, the GW sends a SETUP to the CCM, the CCM realizes this GW is configured uder the authority of a GK, so the CCM sends an ARQ to the GK and expects an ACF with other control parameters such as the bandwidth to use and the destination signaling IP. This, of course, follows a successful registration of the GW to the GK by the CCM. it's a bit convoluted, and i think cisco usually recommends you bypass the CCM in these cases, i.e., configure the GW to statically peer with other H323-capable endpoints. i think the prime role of the CCM is to smooth out the integration of skinny clients into the VoIP network, without the need of chaging the pre-established protocols such as H323.

E.