Understanding How the Media Gateway Peer Call Server Handles and Routes Calls Within the Branch for SRX Series Integrated Convergence Services

This topic covers how calls within the branch are handled by the peer call server, which is responsible for routing them under normal circumstances. It addresses how the peer call server handles calls to and from analog and SIP stations.

When it receives a call destined for an extension at the branch, the peer call server applies services to it, depending on its configuration and the station configuration, and then it routes the call to the SRX Series media gateway (SRX Series MGW). Depending on the peer call server, the call handling services provided might include auto attendant, caller ID, direct inward dialing (DID), voicemail, and so forth.

The peer call server relies on its dial plan to determine how to route calls. A dial plan includes routing entries with digit patterns. If the peer call server’s dial plan includes a routing entry with a digit pattern that a called number matches, the peer call server routes the call to its destination.

The peer call server and the media gateway interact in the following ways:

• For analog telephones and fax machines at the branch.
  • The SRX Series MGW registers analog stations.
  • For calls from analog stations, the SRX Series MGW converts the analog signal to a digital one using the preferred, negotiated codec before it routes the call to the peer call server across the IP WAN.
  • The peer call server applies call handling services and routes the call to its destination as follows:
    • If the call is destined for an analog telephone at the branch, the peer call server routes the call to the SRX Series MGW. The SRX Series MGW converts the digital signal to an analog one and forwards it to the station of the called party.
    • If the call is destined for a SIP phone at the branch, the peer call server routes the call directly to the SIP phone.
• For calls from SIP phones at the branch.

  Because they are from IP telephones (digital signals), SIP phones register directly to the peer call server. The peer call server applies call services and routes the call to its destination as follows:

  • If the call is directed to another SIP phone, the peer call server routes it directly to the phone, if a station is configured for it. SIP stations can be configured discretely or through an extension-inherit range. SIP phones that are not registered can use the guest feature, if you configure it.
  • If the call is destined for an analog telephone at the branch, the peer call server routes it to the SRX Series MGW to convert the call to an analog signal. The SRX Series MGW forwards the call to the destination analog station.

Related Topics

• Understanding the Media Gateway Peer Call Server for SRX Series Integrated Convergence Services
• Understanding How the Media Gateway Peer Call Server Handles and Routes Calls Outside the Branch for SRX Series Integrated Convergence Services
• Example: Configuring an Integrated Convergence Services Basic Media Gateway