[cisco-voip] Best practice for handling emergency calls

[Matthew Melbourne]

I am interested in finding out what others do for handling emergency calls
(specifically 999/112 in the UK), in centralised multi-site deployments. In
the UK, DNs are registered on a database which provides the DN-to-address
mapping. With Extension Mobility, users' numbers may move between sites so
can't accurately reflect location. I have used one technique where the
Device CSS is used to point towards a unique 'emergency' partition which
contains a Route Pattern which presents a specific, registered, DN for that
site by manipulating the outbound CLI (and the Line CSS effectively manages
the Class of Service). However, for a large number of sites this quickly
becomes a management issue, and any phone moves must have their Device CSS
updated accordingly.

A similar idea could be used for sending emergency calls out from a local
FXO port at each site (rather than through centrally-located trunks).
Similar CSS/Partition arrangements still may be required, although this may
be easier to implement achieve with the use of local route groups in CUCM
7.x.

Are there any other possible solutions; can CER operate in a non-US
environment?

Cheers,

Matt

-- 
Matthew Melbourne