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Dialogic® 4000 Media Gateway Series Reference Guide
page 47
Every route defines only one direction. Therefore, at least two routes are needed to support both PSTN-to-SIP
and SIP-to-PSTN connections. The basic call (without address manipulation) is processed as follows:
Some things to know about call processing
• Each route may point to several destinations, between which the Diva SIPcontrol software chooses according
to the following settings (in decreasing order of importance):
• availability (destination enabled),
• alive state of destination (if enabled to be verified),
• priority (Master/Slave),
• channel load quota (a factor calculated by comparing used vs. total supported channels).
• For each call only one route is chosen. Even if another route would also match the call criteria, only the first
matching route is ever evaluated. Therefore, default routes should be created carefully.
• Load balancing/failover is only performed between the destinations of a single route.
• Routes without any conditions always match (as long as the source endpoint is listed in route sources).
1.
Find and assign an endpoint for an incoming call
request (PSTN: lookup by CAPI controller
number; SIP: lookup by "From" address of
received message).
2.
Go sequentially through the list of routes and
find the first route that has this endpoint
defined in its configured sources list.
3.
Determine whether at least one call address
condition of this route matches simultaneously
the called, calling, and redirected addresses of
the call request; if not, find another route.
4.
If any route condition matches, verify in the list
of configured destinations which one is the
most preferred. This is done based on settings.
See
Some things to know about call processing
below for more information.
5.
Try to establish the call via this destination. If
the destination is unavailable or rejects the call,
try the next destination of the route. Note that
the call will be aborted immediately if a cause
code is received that signals final failure, e.g.,
user busy or unallocated number.
6.
The call is established.