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New Member

ICT = H323 Gateway ?

Does anyone know the technical differences between an ICT link and a H323 gateway link? They are both H323 based but I can't find anything on CCO that specifically states what ICT provides and the detail. The reason I ask is that we have a customer you has a 3rd party application configured on CCM via an ICT and it appears to be working fine (its a H323 based app).


Re: ICT = H323 Gateway ?

"An intercluster trunk is just an special case of an H323 GW, [...]The H323 signalling used between CCM servers configured for ICT contains some additional messages that are not found when CCM comunicates with an H323 GW)"

Those messages are related to media negotiation.

One other distinction between ICT and IP trunks to GWs is that CCM supports H323 Annex M, which permit the tunneling of Q.SIg over H323.

You can gather a CCM detailed trace for an ICT trunk connection and other for GW and check all H245 messages and Media Negotiation, so you can compare them deeper.



New Member

Re: ICT = H323 Gateway ?

In simple words, if you have IP connectivity (say, wan link) between 2 callmanager clusters and you want communication between these 2 clusters, then you can simply use an ICT. This is a link controlled by H.225.

We won't be using an H.323 gateway for the above scenario because we do not require the routing capabilities of a gateway to connect these 2 clusters. We can utilise the gateway to route calls to the PSTN, maybe (if that is a requirement).

Lemme know if you require further clarification.

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