Tadiran Telecom aeonix TGW4, User Manual, Page: 134 / 141

User Manual
T G W S IP -F X S /F S O G a te w a y S e rie s
118
Tadiran Telecom
5
Appendix: High availability configuration
Function Definition 5.1
In the deployment of VoIP network, Tadiran Telecom TGW SIP-FXS/FXO Gateway (referred as
gateway below) supports high availability architecture with Primary-Standby , Active-Standby and
Load balancing mode.
Primary-Standby mode
In this mode, a backup SIP proxy server (referred as SIP server) is configured. The gateway will
failover to the backup server automatically when the primary server faults. The gateway detects the
failure condition of primary server by sending OPTIONS request to it. If the gateway does not receive
the response to OPTIONS request, it will failover to the backup server.
After failover to the backup server, the gateway will still send OPTIONS to the primary server all the
time. It switches back to the primary server once the response to the OPTIONS request is received.
Active-Standby mode
In this mode, one SIP proxy server (referred as SIP server) functions as the primary server while other
SIP servers function as standby servers.
Either of the following conditions could trigger the failover operation of the gateway:

Not receiving response to the OPTIONS message from the current SIP server to which the gateway
sends or receives call traffic;

Not receiving response to the REGISTER/INVITE message from the current SIP server to which the
gateway send or receives call traffic
The administrator can manually switchover the gateway from the current SIP server to the next
available one.
The gateway will redirect call traffic to the designated proxy server in responding to the re-INVITE
from the server.
Load balancing mode
In this mode, the clustered SIP servers are all working in active status. Under the coarse grained scheme
all endpoints of a gateway are allowed to register on one of the designated servers and under the fine
grained scheme the endpoints of a gateway are allowed to register on multiple servers, according to the
administrator’s load balancing plan. The following features are supported with load balancing:

The gateway as a whole or endpoints search for the designated sever in the server cluster (a list of
servers) using REGISTER/INVITE message in forward circular scheme.

Server failure detetion is supported by gateway sending OPTIONS to each servers, on which the
gateway or endpoints are registered on.