The Cisco Unified Communications feature called Mobile Connect (also familiarly referred to as Single Number Reach) is truly a great feature of Unified Communications Manager, and can provide us with many efficiencies both in being able to be reachable just about anywhere, and in being able to be easily identified when placing inbound calls from our mobile phones into the CUCM cluster to our colleagues. As admins, we know that if we wish to have our users place calls from their mobile phones inbound to their colleagues inside the CUCM cluster, that we need to match up all or at least part of their inbound calling party number (CLID) to their CUCM Remote Destination. But what happens when what the carrier is sending CLID digits inbound to our IOS voice gateways that differs significantly from our Remote Destinations in CUCM, especially if we have truly embraced Cisco’s push toward true Globalization in v7.0, v8.0 & v8.5?

The fact is that many, if not most European carriers (as well as many more all over the world) send CLID in through an ISDN PRI into the enterprise gateway with a preceding “0″ as a courtesy  digit for easy recognition and ease in dialing back out, since this “0″ is very commonly used as a carrier-recognized national dialing prefix. If we were speaking of the US and Canada, this “0″ we are speaking of would be akin to dialing a “1″ prior to the national number. Now in the US and Canada, if a carrier in the US sent CLID into a gateway with a “1″ preceding any 10 digit number, this would work fine since the US/Canada country code also happens to be “1″. However, the “0″ preceding a variable length number is not valid in a true E.164 number format (e.g. If you dialed the phone number from outside of whatever country we were talking about, you would omit that preceding 0 from your dialed digits).

So what are we to do to get our inbound CLID to match our RD’s?

That is exactly what we will explore here today in video format, as you watch a very small excerpt from our video-based solutions to one of the many new labs we will have in our new CCIE Voice Volume I & II workbooks.

Click here for the 25 minute video discussion on “The Trouble with European MGCP Gateways and Mobile Connect Inbound Calling Party Matching.

(BTW, if the video starts off with a bit of an echo, just hit CTRL-R to refresh the stream. And then stay tuned to this blog for some very exciting announcements about new formats for video solutions in the very near future)

Happy Labbing,


About Mark Snow, CCIE #14073:

Mark Snow has been actively working with data and traditional telephony as a Network Consulting Engineer since 1995, and has been working with Cisco Call Manager and voice-over technology since 1998. Mark has been actively teaching and developing content for the CCIE Voice track since 2005, and the Security track since 2007. Mark's story with both data and voice technology started out quite young, as he began learning around the age of five from his father who was a patented inventor and a research scientist at AT&T Bell Laboratories. Mark started out on Unix System V and basic analog telephony, and went on from there to large data networking projects with technologies such as Banyan Vines, IPX and of course IP, and large phone systems such as Nortel 61c, Tadiran Coral, Avaya Definity and of course Cisco Unified Communications Manager in both enterprise and 911 PSAP environments across the US and internationally. Mark is also an accomplished pilot and punched his ticket in 2001. When Mark isn't learning, labing, consulting or teaching, he can be found either piloting or possibly jumping out of a perfectly good airplane, hanging off a rock somewhere or else skiing out west. He also might just be enjoying a quiet day at the beach with his wife and two wonderful young kids, Ryleigh and Judah.

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2 Responses to “The Trouble with European MGCP Gateways and Mobile Connect Inbound Calling Party Matching”

  1. [...] This post was mentioned on Twitter by Internetwork Expert, Anderson Dias. Anderson Dias said: RT @inetraining: The Trouble with European MGCP Gateways and Mobile Connect Inbound Calling Party Matching http://bit.ly/gy9alV [...]

  2. [...] series on CCIE Voice Troubleshooting and issues you may encounter during your lab exam, we last looked at problems with European MGCP GWs and Mobile Connect, and today we would like to continue that series by exploring the issues that you might run into in [...]


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