Nortel Networks SRG50 manual Recovery to normal mode, Testing the telephone in local mode

Chapter 4 CS 1000 considerations 37

If the main office Signaling Server fails and an Alternate Signaling Server is available, the SRG IP Phones reset and reregister with the SRG. The SRG will then query the NCS for the Alternate Signaling Server’s IP address. The SRG will redirect the IP Phone to the Alternate Signaling Server and continue to receive call processing services from the main office Call Server. If no Alternate Signaling Server is available, the SRG IP Phones reset and register with the SRG in local mode.

When an IP Phone at the SRG first boots up, the IP Phone attempts to communicate with the SRG. After communication with the SRG is established, the SRG redirects the IP Phone to the main office. When the SRG IP Phone attempts to register with the main office, the SRG first queries the Primary NRS for the main office Virtual Trunk node IP address to redirect the IP Phone. If the Primary NRS is down or unreachable, the SRG queries the Alternate NRS, if one is specified. If it receives a positive response, the SRG IP Phone is redirected to the specified main office. Otherwise, if neither a Primary or an Alternate NRS is available, the SRG IP Phone remains in local mode, and receives call processing services from the SRG until communication can be reestablished.

SRG IP Phones in normal mode remain registered with the main office if the Primary NRS fails and no Alternate NRS is available. They can call any main office telephone or IP Phones in normal mode in other branch offices.

SIP/ H323 trunks are used for Voice traffic alone. Proprietary TPSAR protocol is used for WAN link health check and for Main Office TPS address discovery through NRS.

However, they cannot call any SRG analog (500/2500-type) telephones or any external numbers through the SRG trunks because the Virtual Trunks are not available. (SRG analog [500/ 2500-type] telephones are accessible if alternate routing is available through the PSTN.)

For more information about virtual trunks for SRG50, see the Main Office Configuration for Survivable Remote Gateway 50 (NN43001-307).

Recovery to normal mode

Once communication is re-established with the main office call server, all IP Phones at the branch office that are in local mode automatically redirect and reregister to the main office and return to normal mode operation. IP Phones that were busy at the time communication was reestablished complete the call in local mode, and then reregister with the main office after the call is complete.

Testing the telephone in local mode

From normal mode, the branch user has the option of going to local mode manually using the Test local mode feature. The test can be performed by the user at any time and does not require a password. This test is invoked from any IP Phone at the branch office.

Nortel recommends testing local mode operation after changing the provisioning for a telephone on the SRG.

To ensure that users do not forget to resume normal mode operation, the SRG redirects the telephone to the main office to return the telephone to normal mode. This occurs if the telephone remains registered to the SRG in test local mode for ten minutes (default setting). Alternatively, the user can press the Quit key from the set to return to normal mode.

SRG50 Configuration Guide