BCM 50 VoIP numbering plan

[ccarmock]

I know ideally when networking a number of BCMs together the best option is to have differing extension number ranges at each site. However I have a situation where we have three BCM50s all on the default extension range ie starting 221. We don't want to change the extension numbering or length at any of the sites if possible.

So I thought I could define routes with prefix digts 81 and 82 to route calls from Site A to Site B & Site C respectively.

However when I pass the call to the VoIP trunks if I don't absort ALL on the route then I find the BCM tries to send the prefix digits to the remote site which means the destination isn't recognised on the other switch.

If I do absorb ALL on the route then there is no routing digit supplied to the VoIP trunk to use to select which site to send the call to.

Numbering plan is CDP.

When I have done this before on the CS1000's we use a CDP plan but don't delete any digits when processing the RLB so the ITG trunk cards see the leadign digitas and can strip them off and route the call to the correct site.

Is there a recommended way to do this on the BCMs?

Regards
CLive

 

[telcodog]

If you're going to do it that way, you have to put routes in your voip trunk route table under resources. You have to specify your 81 and 82 and tell it what the destination ip addresses are (your far end BCMs) in the same way you would do if you had different extension extension numbers, and you should also have an MCDN license.

 

[ccarmock]

Thanks for that - I can get that bit working by putting routes under resources for 81 and 82 specifying different IP addresses for the destination systems. However the source BCM will send the 81 & 82 as part of the dialed number to the destination BCM which won't recognise it.

Is there a way to strip the prefix digits off at teh VOIP stage as opposed to usign absob all int he route?

 

[Frideo]

Is there a way to strip the prefix digits off at teh VOIP stage as opposed to usign absob all int he route?"


There's no way to do that. I can see your dilemma:

If you absorb all in the main routing, then you only send "221" to the IP Trunk routing, which cannot know where to send it.
If you absorb nothing, then you send "81221" to the IP Trunk routing, which is not what you want.

However, is it really a problem if you send "81221" to the remote BCM?
Surely if the Private Network dialing plan is set to use 3 digts, then it'll use the last three digits - 221 - and ignore the 81 at the beginning.

 

[ccarmock]

Thats the exact problen yes - depending on where the 81 is stripped off I can either make a routing choice or not.

I must admit I didn't know that the BCM would only use the last three digits I thoguht it would use the first three. if it is the last three that will solve my problem.

When I have done this before on a CS1000 the prefix digits can be stripped off my the ITG card after the destination is selected so it only sends the actual DN digits.

The Nortel documentation is not too bad in this area, but does not cater for the situation where the BCMs might have overlapping DN ranges.

I guess there is no way to tell a BCM to ignore prefix digits it receives IN via a VoIP trunk?

CLive

 

[snowman50]

Try setting the Private receive lenght for your target lines to 5 digits that way you send 81221 to the bcm and point that target line to extn 221 same as using Public Receive digits.

Then allow your route to send all 5 digits.

 

[rball22]

For what its worth. We were faced with this same scenario and fought it for over a month before we finally gave in and made all locations 4 digits and front ended each location with a different number. Site A = 1221 Site B = 3221 Site C=4221. This also fixed our centralized voicemail issues of notification lights.