Nortel ISDN Signaling Link, Description, Installation And Operation

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Page 58 of 378 Description
553-3001-202 Standard 1.00 April 2000
route is not configured in the route list, the calls rejected by the IP trunk will
be routed to some other treatment. Fallback is optional, based on the
configuration of the route list.
Figure 11 shows the Fallback to alternate facilities functionality.
Figure 11
Example of a Fallback to alternate facilities situation
Return to the IP network
Unless the DCH is down and all trunks appear busy to the Meridian 1, it
always introduces outgoing calls to the ITG node. Each call is tested against
the outgoing address translation and Quality of Service (QoS) for the
destination node. After the QoS returns to an acceptable level, all new
IP
Network
PSTN
MMCS
IP Gateway
MMCS
IP Gateway
Terminating CPE Originating CPE
IP network QoS falls below
customer-defined level
ITG card recognizes
IP network QoS is
below acceptable
level and decides to
use other facilities to
route the call.
Call is routed
through the PSTN
553-9480