This topic describes multisite connection options.
The figure shows a Cisco Unified Communications Manager cluster at the main site with these connections:
In addition to the connection to the main site cluster, the remote cluster has the following connections:
- Local MGCP gateway
- Connection to the Internet through Cisco Expressway Series
Cisco Unified Communications Manager Connection Options Overview
In Cisco Unified Communications Manager, you can configure gateways and trunks for connections to the PSTNor to other call control systems.
- Connection to any SIP device
- Direct connection to another Cisco Unified Communications Manager cluster
- Connection to any H.323 device via a gatekeeper
- H.323 (any H.323 device when not using a gatekeeper)
You can configure trunks and gateways when you connect to devices that allow access to multiple endpoints. If the destination is a single endpoint, you can configure a phone as SCCP, SIP, or H.323.
Gateways are configured by the signaling protocol that they use. Cisco Unified Communications Manager supports H.323, MGCP, and SCCP gateways. Trunks can be configured as H.323 trunks (three types are available) or SIP trunks.
You can use H.323 trunks only when connecting to another Cisco Unified Communications Manager cluster, to Cisco Unified Communications Manager Business Edition, or when using an H.323 gatekeeper.
You can configure an H.323 gateway when you connect to any other H.323 device that is not an endpoint. Such devices can be Cisco IOS H.323 gateways or H.323 gateways of other vendors.
Cisco IOS Gateway Protocol Functions Review
The table shows Cisco IOS gateway protocol functions by protocol.
|QSIG||Supported||Not supported||Not supported|
|Fractional T1/E1||More effort to implement||Easy to implement||Easy to implement|
|Signaling protocol||TCP and UDP||TCP||TCP or UDP|
|Code basis||ASCII||Binary (ASN.1)||ASCII|
|Call applications usable||No||Yes||Yes|
As shown in the table, the three main gateway signaling protocols—MGCP, H.323, and SIP—provide various features and functions when implemented with Cisco Unified Communications Manager and Cisco IOS gateways.