Incoming SIP to Outgoing ISDN
There are two ways to route the call: low-cost routing or first-free-channel routing.
Least Cost Routing
When a SIP call is received, the gateway looks at the 'to' field information and if the "trunk" string is found in the called party
information, the next character specifies what span the call should be routed on.
For example, assume all 4 spans are up and a call is received in the SIP side as
follows:
from = [email protected]
to = [email protected]
The 'to' field above contains the string "trunk" (or "TRUNK"), so the next character
is looked at, which is a letter "c'"(or "C").
The "c" indicates that span 3 should be use when making the outgoing ISDN call. So,
the outgoing call would be made on
the first free ISDN channel found on span 3 and it would look as follows:
from = 123456
to = 115161
If an "A" was found, span 1 would be used. If a "B'" was found, span 2 would be
used, etc. If there are no free channels
on the specified span, the call is rejected.
If the word "trunk" is not found, first-free-channel routing is used.
6.3 SIP Settings Screen
PIKA FormulaT1/E1 Gateway 1.0 User Guide
Call Routing Examples
11/2/2007
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