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Global Dial Plan - Gatekeeper Technology Prefixes

This is a long one, sorry.

Trying to figure out a way to have a scalable global dial plan while forcing calls to DN's on-net. To do that "automatically" without having to constantly train users about who's on-net vs. off makes this harder than it sounds.

Since I can't do centralized trunking yet (politics), I'm trying to figure out a way to define all DID's (globally) in one, or few, servers/gatekeepers instead of on every cluster.

Trying to figure out if Gatekeeper technology prefixes will help do this.

Call Manager will do the class-of-service admission, and translate every number into an int'l dial string (such as 1-651-777-5xxx for US or 49-211-333-xxxx for Dusseldorf).

From there, all calls would be sent to a local IOS gateway. A high preference dial peer would send every call to a gatekeeper with a tech prefix that is unique to that gateway.

Here's where I don't know of tech prefixes will make this work. If there is a zone prefix match (meaning an internal DN defined that goes to CCM) then it would hopefully go to that CCM's ICT and be an internal call.

If no zone prefix match, then would the call get sent back to the gateway designated as that tech prefix? With the tech prefix still in front of the original number?

If so, then I'd have a dial peer with that tech prefix configured to go out the PSTN.

The way I read the docs is that tech prefix will override a zone prefix match. But that would make them useless for anything but a default gateway type of thing so I wanted to ask.

Thanks for your time.

4 REPLIES
Bronze

Re: Global Dial Plan - Gatekeeper Technology Prefixes

Here is the difference between zone prefix and tech prefix:

Zone prefix identifies if a zone is local or remote. That's all it does. If zone is local, it will look for tech prefix to find a gateway. If zone is remote, it will forward LRQ to remote GK.

Tech prefix selects the gateway. For ex. if dialed number is 88#123456789 and there is a gateway that is registered with tech prefix 88#, the GK will select that gateway.

Here is a very good info about gatekeeper routing http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00800a8928.shtml

New Member

Re: Global Dial Plan - Gatekeeper Technology Prefixes

Thanks for the info!

New Member

Re: Global Dial Plan - Gatekeeper Technology Prefixes

Would it be correct to say that a zone prefix is not the same as a "registered E.164" ?

As you mentioned, the zone simply indicates that the called number is local to the gatekeeper. Then the GK looks for a "registered" E.164 within that zone, which is an FXS port or something - ?

Thanks again.

Re: Global Dial Plan - Gatekeeper Technology Prefixes

Chad,

Zone prefix is not the same as a registered e.164 number. if a device registers to a gatekeeper using e164, the gatekeeper can easily route the call based on that number. Zone prefixes are used in combination with techprefixes to route calls in cases where you dont have an option to register extensions as e164 numbers. For example, callmanager cannot register to a gatekeeper with e164 numbers. (while CME can).

Here is a diagram that indicates how gatekeeper routes a call. Look at the first picture in this link.

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00800a8928.shtml

HTH

Sankar

PS: please remember to rate posts!

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