Polycom 3725-76302-001LI manual External SBC, Column Description

External SBC Device Management

External SBC

On the External SBC page, you can add or remove H.323 SBC (session border controller) units (Polycom VBP appliances are supported) from the list of such devices that the system can use. In an H.323 environment, H.323 SBCs regulate access across the firewall.

This is a supercluster-wide configuration.

Note

This page is only for H.323 SBCs. SIP SBCs are configured as SIP peers. See “External SIP Peer” on page 108.

For most configurations, H.323 SBCs should be configured on a per site basis on the Sites page. There are three reasons to configure an H.323 SBC on the External SBC page:

•To create a prefix service that allows dialing through the specific SBC by prefix.

•To define a postliminary script to be applied when dialing through the SBC.

•For bandwidth management.

The Polycom DMA system is capable of performing call admission control (CAC) while processing an LRQ from a neighbor gatekeeper. This allows the system to reject the call for resource or policy reasons early in the setup process (in response to the LRQ), rather than waiting until later in the call setup.

In order to perform early CAC, the Polycom DMA system must know the caller’s media address, which isn’t provided in the LRQ and is unknowable for an ordinary gatekeeper. If the gatekeeper is also an SBC, however, it proxies the media. The Polycom DMA system can assume that its media address is the same as its signaling address, and proceed with early CAC. The Polycom DMA system performs early CAC only in response to LRQs received from SBCs configured on the External SBC page.

The following table describes the fields in the list.

Table 5-23Fields in the External SBC list

Column	Description
Name	The name of the SBC.
Description	Brief description of the SBC.
Address	Host name or IP address of the SBC.

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