The new family of ISR routers provided by Cisco make great media gateways for PSTN connectivity and make a very nice IP enabled key system replacement. Unfortunately, the solution can be pricey and lacks some of the flexibility and functionality of Asterisk.

Our requirement was to integrate two offices, one with a CCME based install and the other a full Asterisk/SIP deployment with IVR and voice mail. The goal was to allow seamless dialing between the two offices maintaining the legacy extension numbers as well as allowing DID to all extensions. The CCME site had no provision for voice mail (without the purchase of a Cisco unity express module and licensing..$$$$) so the goal was also to gain seamless voice mail integration.





(:exclaim:)Warning - I've run into problems getting IOS 12.3(15) working with the following examples. Many of the commands shown were not available; things like the system message command, for example. An upgrade to 12.4(2)T solved the issues. I am running this test of CME on a 3745. Carry on. - RickL

The below is a subset of the full configuration with only the relevant parts, there is no provision for dialing out the PRI etc..etc. nor does it contain any fail over configuration, a sensible configuration would provide a higher precedence call route via the PSTN should the SIP session establishment fail.

There are also many references to e164 numbers... I have replaced our private numbers with a generic 5555xxx range which is no really valid, it should be possible to re-populate the configuration with full e164 numbers but it will probably need some changes at both ends to work properly as I've hacked the config significantly. i suggest using full e164 numbers where possible, it makes the system more extendable and things like ENUM easy.





I won't touch on the SIP config, it is assumed you have a working configuration and your sip based phones are available on channel SIP/extension. The contexts shown below will also need to be included or copied into the appropriate places in your existing configuration.

extensions.conf




MWI is not perfect due to a possible bug and RFC compliance issue (discussed here. The solution is quite workable but not ideal, it would be nice to not have to have all the sip registration mess but.. meh..

In my configuration I chose to register the extension number (it get tiresome listening to Alison reading the full e164 number). The following config makes this work.

Cisco
;Defines the sip-ua registration parameters.
sip-ua
registrar ipv4:10.0.0.200 expires 3600 secondary
sip-server ipv4:10.0.0.200

;Defines where the mailbox status messages will be coming from.
telephony-service
voicemail 105
mwi sip-server 10.0.0.200 unsolicited

;Defines 204 as the secondary number (the primary is the e164 number), above in the register line you can see the secondary
;number is the one used for registration
ephone-dn 3 dual-line
number 204

sip.conf
;Each extension must be configured setting the relevant mailbox as described in voicemail.conf
[204]
context=cme
type=friend
host=dynamic
canreinvite=no
mailbox=204

voicemail.conf
201 => 201,Test User,user@company.com
204 => 201,Test User,user@company.com



Thanks to Kurt W. Pasewaldt, who's page I found after when searching for information on MWI, Kurt should be credited this information

http://www.pasewaldt.com/cme/cme_index.htm

The "redirect ip2ip" is needed in IOS 123.14T or greater because of the following bug reference: CSCef72436.

Kurt Pasewaldt




You can see another example with a Cisco 2801 and a VIC2-2BRI-NT/TE on http://vt100.at/?site=doc/105

Harald Klein


Questions relating to the above configuration sould be directed to me at nathanalberti.com