Tuesday, August 19, 2008

Cisco and Nokia Dual Mode Part III : Mobility my way

After having configured the networking part of the problem here and then refined roaming here, time's to expose the Communications Manager side.

Targets were simple :
  • People who have a dual-mode phone should always be reachable via IP if in WLAN coverage, regardless the caller dialed the office number or the mobile number.
  • People who have a dual-mode phone should not be always reachable regardless the number dialed, but only if called on the cellular number, no automatic call diverting from the office number to the mobile number.
  • The configuration should be as simple as possible and possibly cheap in terms of DLU

We decided not to implement the entire Cisco Mobility suite, but a subset of functions so saving DLUs and having the funtionality we needed.

Extension Mobility is enabled on all the IP Phones and users. Each desk phone has a dummy (not valid on the PSTN) line in a partition called Logout, from which can call only other desk phones, logged in users and emergency (there's a transformation pattern to make it exit on the PSTN).

Each user has a device profile with his personal line in a partition called Login (where all the logged in lines are).

Each dual-mode nokia mobile has two lines : the first shared with the device profile, the second belonging to a partition called Dual-Mode, unreacheable by anyone except from a particular CSS used by translation patterns.

This way behavior is :
People dialing the user's line while he is logged off from the desk phone and not under WLAN coverage (away) get fast busy or is redirected to VoiceMail.


People dialing the user's line while he is logged off from the desk phone but he is under WLAN coverage succeed in connecting since the line is active on the mobile through the Nokia IntelliSync Call Connect for Cisco.

People dialing the user's line while he is logged in and under WLAN coverage makes both the phones ring (shared line). Two notes on this : while in conversation on the mobile you can put the call on hold and then resume it from the desk phone (useful if you answer while away and the you reach your office), if you answer from the desk phone while both ringing, on the mobile you'll find a fake missed call.

People dialing the user's mobile number while he is under WLAN coverage will have their call translated to the "hidden" line on the mobile so using VoIP.

People dialing the user's mobile number while he is not under WLAN coverage will have their call translated to the "hidden" line on the mobile which have a call forward unregistered entry to the real mobile number.

Here's how this is configurated :

Partitions :
Logout : All the devices with no device profile logged in.
Login : All the lines of the device profiles
DualMode : All the "hidden" second lines on the nokia mobiles.

Desk Phone :
1000 in Logout partition.

Device Profile :
2000 in Login partition.


Mobile Phone :
2000 in Login partition.

7000 in DualMode partition.
Call Forward Unregistered on #3331234567 (mobile number)

Translation Pattern :
03331234567 becomes 7000
This one makes people looking for you on the mobile being translated on VoIP.

Route Pattern :
#.[3]! -> PreDot discard and prepend 0.
If you are not under WLAN coverage, the CFU to #3331234567 is routed to your real mobile. This is necessary because redirecting on the real number (03331234567) would meake the call enter a loop (the above mentioned translation pattern...)

Here's some self-explaining slides :

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