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Call Routing Based on Unregistered DN

Is there anyway unregistered DN can rerouted via PSTN on 4.1.3?

Thanks in Advance


Re: Call Routing Based on Unregistered DN

Not in 4.1(3) as far as I know, not automatically, anyways.

SRND 4.2

Cisco Unified CallManager 4.2 introduces the Call Forward Unregistered (CFUR) feature as a way to reroute calls placed to a temporarily unregistered

destination phone. The configuration of CFUR consists

of two main elements:

.Destination selection

When the DN is unregistered, calls can be rerouted to

either of the following destinations:


Calls can be sent to voicemail by selecting the

voicemail checkbox and configuring the CFUR calling

search space to contain the partition of the voicemail

pilot number.

-A directory number used to reach the phone through

the PSTN

This approach is preferred when a phone is located

within a site whose WAN link is down. If the site is

equipped with Survivable Remote Site Telephony, the

phone (and its co-located PSTN gateway) will

re-register with the co-located SRST router. The phone

is then able to receive calls placed to its PSTN DID


In this case, the appropriate CFUR destination is the

corresponding PSTN DID number of the original

destination DN. Configure this PSTN DID in the

destination field, along with applicable access codes

and prefixes (for example, 9 1 415 555 1234).

.Calling search space

Cisco Unified CallManager attempts to route the call

to the configured destination number by using the

called DN's CFUR calling search space. The CFUR

calling search space is configured on the target phone

and is used by all devices calling the unregistered

phone. This means that all calling devices will use

the same combination of route pattern, route list,

route group, and gateway to place the call, and that

all CFUR calls to a given unregistered device will be

routed through the same unique gateway regardless of

where the calling phone is located. Cisco recommends

that you select a centralized gateway as the egress

point to the PSTN for CFUR calls and that you

configure the CFUR calling search space to route calls

to the CFUR destination to this centralized gateway.

The Call Forward Unregistered functionality can result

in telephony routing loops if a phone is unregistered

while the gateway associated with the phone's DID

number is still under control of Cisco Unified

CallManager, as is the case if a phone is simply

disconnected from the network. In such a case, the

initial call to the phone would prompt the system to

attempt a first CFUR call to the phone's DID through

the PSTN. The resulting incoming PSTN call would in

turn trigger another CFUR attempt to reach the same

phone's DN, triggering yet another CFUR call from the

central PSTN gateway through the PSTN. This cycle

could repeat itself until system resources are


The new service parameter

MaximumForwardUnRegisteredHopsToDn controls the

maximum number of CFUR calls that are allowed for a DN

at the same time. The default value of 0 means the

counter is disabled. If any DNs are configured to

reroute CFUR calls through the PSTN, loop prevention

is required. Configuring this service parameter to a

value of 1 would stop CFUR attempts as soon as a

single call is placed through the CFUR mechanism. This

setting would also allow only one call to be forwarded

to voicemail, if CFUR is so configured. Configuring

this service parameter to a value of 2 would allow for

up to two simultaneous callers to reach the voicemail

of a DN whose CFUR setting is configured for

voicemail, while also limiting potential loops to two

for DNs whose CFUR configuration sends calls through

the PSTN.

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