Disabling forwarding calls to each other

flopez · ‎01-15-2008

I didn't know this was possible, but one of my users at extension 1501 was able to forward her calls to extension 1502. 1502 also had her phone forwarded to 1501. CCM allows you to do this, why? Is there a way to disable this from happening.

BTW, I am using CCM 4.1.3 and Unity 4.1

Rob Huffman · ‎01-15-2008

Hi Julio,

This issue has not yet been fixed, this is a known bug (feature request). For the time being you will have to educate your users to be careful when forwarding;

CSCds43736 Bug Details

Headline Feature Req: Call Fwd loops should be handled gracefully by CM

Product ciscocm

First Found-in Version 3.0(3a)

Status Assigned

Feature request:

When two or more phones are forwarded to create a forward loop CM will

tear down the call when it reaches the ForwardMaximumHopCount.

The CM should handle this as follows:

PhoneA fwd Phone B

PhoneB fwd Phone C

PhoneC fwd Phone A

When you call Phone A from Phone X the Call Manager will ignore the loop and

Phone C will ring.

Following the same principle when Phone B is called, the call should go to

Phone A as it is the last hop before the loop.

From this good doc;

Cisco CallManager Issues with Call Forward All

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a00801b3f4b.shtml#t5

Hope this helps! Sorry man.

Rob

flopez · ‎01-15-2008

Thanks for the link Rob.

This issue is bad...really bad.... ;)

Rob Huffman · ‎01-15-2008

Hi Julio,

You are most welcome :) There are some tips for mitigating this issue in this good doc;

Cisco CallManager Loop Avoidance Guide to Best Practices

http://www.cisco.com/en/US/netsol/ns340/ns394/ns165/ns391/networking_solutions_design_guidance09186a00801f8e28.html#wp41158

And there is hope on the horizon in CCM 6.x, although I understand there are still a few wrinkles to work out;

Call Forward All Loop Prevention Message Changes

Changes for the following error messages that display on the phones for Call Forward All (CFA) loop prevention occurred:

â€¢When a user activates CFA from a phone, resulting in a CFA loop:

-Original error message: "Call Forward Loop"

-New error message: "CFwdAll Loop Detected"

Release Notes for Cisco Unified Communications Manager Release 6.0(1)

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/rel_notes/6_0_1/601cmrn.html#wp80207

Hope this helps!

Rob

Aaron Dhiman · ‎01-16-2008

Given this bug, if your users hop around a lot, you might just have them use Extension Mobility instead...