You can configure the following types of VOIP on Zhone devices:
Session Initiation Protocol (SIP)
SIP Private-line automatic ringdown (PLAR)
Media Gateway Control Protocol (MGCP)
H.248
Zhone devices support these additional voice services:
Emergency Stand Alone (ESA)
T.38 fax
SIP signaling identifies callers and callees by SIP addresses and allows signals to be redirected to proxy servers.
Zhone devices support single softswitch configurations for SIP.
There is no need to create a VOIP server entry for SIP PLAR server. It is created automatically when you add a SIP PLAR connection.
MGCP signaling establishes call control elements or call agents to handle call control. MGCP devices execute the commands sent by the call agents.
Zhone devices can support redundant MGCP servers per VoIP system. In order to support multiple MGCP servers, the servers must be configured as redundant MGCP servers with redundant peer support enabled. When the system boots up, it determines which redundant MGCP server use.
The H.248 protocol is used between elements of a physically decomposed multimedia gateway. The distributed multimedia gateway sub-components create a general framework used for gateways, multipoint control units and interactive voice response units (IVRs).
SIP and H.248 protocols support the Emergency Stand Alone (ESA) feature.
For VoIP SIP or SIP PLAR voice connections, the Zhone device provides emergency calling services during network or equipment failures that cause a loss of connection to the configured SIP server or voice gateway.
For VoIP SIP or SIP PLAR connections, the ESA feature enables numbers configured within ESA dialplans to communicate with any residences or businesses specified as the destination of the dialplans in an ESA cluster of Zhone devices. Incoming calls from outside the ESA group and outgoing calls to numbers outside the ESA cluster receive a fast-busy signal.
When ESA is activated, call features such as call waiting, are not supported.
Just as with SIP ESA, if the Zhone device loses H.248 communication with the softswitch, it will continue to process calls locally between subscribers in the same Zhone device chassis to another reachable Zhone device in the ESA cluster. POTS subscribers on the same Zhone device can make calls (voice, fax, modem) between each other as well as calls to other reachable Zhone device in the ESA cluster, based on the predefined dial plans for each Zhone device in the ESA cluster.
T.38 fax service enables fax messages to be transported across VoIP networks between G3 fax terminals. When configured for SIP or SIP PLAR and T.38, MXK provides a T.38 fax relay service between two devices configured for the same VoIP protocol. If one side of the T.38 connection is not configured for T.38 support, the fax call reverts to g.711 pass through when this option is configured. Otherwise, the fax may not go through.
For more information about voice support on Zhone devices see the manuals on the Zhone website http://www.zhone.com/support/manuals/.
October 12, 2011