Cisco Cisco Unified Customer Voice Portal 11.0(1)
4-5
Cisco Internet Service Node (ISN) Product Description
OL-1250-03
Chapter 4 VoIP Routing
Inbound Routing
Note
For complete details about the command syntax for setting preferences, see the Cisco IOS
documentation.
documentation.
In this configuration, Huey will attempt to route the call as follows:
•
First, Huey will try connecting to one of the two Voice Browsers in ISN_Node1, since they have the
lowest preference value (0).
lowest preference value (0).
•
Next, if the Voice Browsers in ISN_Node1 do not respond properly, Huey will then attempt to route
the call to the next lowest preference value (1), which is Voice Browser 10.10.10.21 in ISN_Node2.
the call to the next lowest preference value (1), which is Voice Browser 10.10.10.21 in ISN_Node2.
•
Finally, Huey will attempt to route the call to Voice Browser 10.10.10.31 in ISN_Node3.
Inbound Call Routing With a Gatekeeper Present
When a Gatekeeper is present, Inbound call routing to the ISN is controlled by information kept at one
or more H.323 Gatekeepers.
or more H.323 Gatekeepers.
Cisco Gatekeepers provide several capabilities:
•
Zones. H.323 enforces the concept of zones, where a single logical Gatekeeper (which might consist
of one or more actual Gatekeepers) is responsible for routing control within its zone. The Gatekeeper
can be configured to associate each dialed number (or range of numbers) with a prioritized list of
target endpoints, in the case of the ISN, a list of Voice Browsers.
of one or more actual Gatekeepers) is responsible for routing control within its zone. The Gatekeeper
can be configured to associate each dialed number (or range of numbers) with a prioritized list of
target endpoints, in the case of the ISN, a list of Voice Browsers.
When an originating endpoint queries the Gatekeeper for routing information, the Gatekeeper tries
to find the longest match with its list of dialed numbers. If a match is found, the Gatekeeper selects
the associated target with the highest priority, and returns its IP address (along with any alternate
endpoint IP addresses) to the originating endpoint. If all the associated targets for the matched
number have equal priority (and have available resources), then the Gatekeeper selects one of those
targets at random, and returns its IP address (along with any alternate endpoint IP addresses) to the
originating endpoint.
to find the longest match with its list of dialed numbers. If a match is found, the Gatekeeper selects
the associated target with the highest priority, and returns its IP address (along with any alternate
endpoint IP addresses) to the originating endpoint. If all the associated targets for the matched
number have equal priority (and have available resources), then the Gatekeeper selects one of those
targets at random, and returns its IP address (along with any alternate endpoint IP addresses) to the
originating endpoint.
•
Alternate Endpoints. A Gatekeeper can be configured with a list of alternate endpoint IP Addresses
for each target endpoint. When an originating endpoint (that is, a Gateway) queries the Gatekeeper
for routing information, the Gatekeeper returns the IP Address of the target endpoint, plus the IP
Addresses of any alternate endpoints for the primary target. First, the Gateway attempts to route the
call to the primary target. If the primary target does not respond properly, the Gateway tries the other
destinations, in the order defined in the alternate endpoint list.
for each target endpoint. When an originating endpoint (that is, a Gateway) queries the Gatekeeper
for routing information, the Gatekeeper returns the IP Address of the target endpoint, plus the IP
Addresses of any alternate endpoints for the primary target. First, the Gateway attempts to route the
call to the primary target. If the primary target does not respond properly, the Gateway tries the other
destinations, in the order defined in the alternate endpoint list.
•
Out of Service Condition. If the Gatekeeper finds that a target—that is, a Voice Browser—is out of
service (either the Voice Browser has not re-registered during the keep-alive period or has sent a
explicit message to “unregister”), the Gatekeeper will not:
service (either the Voice Browser has not re-registered during the keep-alive period or has sent a
explicit message to “unregister”), the Gatekeeper will not:
–
Choose that Voice Browser as a target. For example, if VB#1 is registered at the Gatekeeper
with VB#2 as its alternate endpoint, and VB#1 goes out of service, then the Gatekeeper will
only return the IP Address for VB#2 (along with IP Addresses for its alternates).
with VB#2 as its alternate endpoint, and VB#1 goes out of service, then the Gatekeeper will
only return the IP Address for VB#2 (along with IP Addresses for its alternates).
–
Update its alternate endpoint lists. For example, if VB #1 is registered at the Gatekeeper with
VB #2 and VB #3 as its alternate endpoints, and VB#2 goes out of service, the Gatekeeper will
still return the IP Address for VB#2 on any lookups where VB#1 is the target endpoint.
VB #2 and VB #3 as its alternate endpoints, and VB#2 goes out of service, the Gatekeeper will
still return the IP Address for VB#2 on any lookups where VB#1 is the target endpoint.
•
Resource Availability/Unavailability. A Voice Browser can also indicate Resource
Unavailability/Availability to the Gatekeeper:
Unavailability/Availability to the Gatekeeper: