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Does SP have PRI T1 virtual bundle service?

I am currently designing two voip sites in the same city. Each one has its own T1 pri trunk to PSTN. For incoming calls, is it possible to virtual-bundle them together to do load balancing? ( they are around 10 miles away from each other physically.) Also if it is, can it do it with number preference? Say, site A has local range 416-555-2000 to 3000, and site B has local range 416-555-4000 to 5000. I would prefer A over B to receive 2000 to 3000, but B over A to receive 4000 to 5000. Do we have that option from carrier?

I know it is a question for service provider. I am just wondering if anyone using this service from their local telecom carrier?

Thanks a lot in advance.


Re: Does SP have PRI T1 virtual bundle service?

Quan Shi:

If you want to have inbound calls treated the same (sharing the T1s) the carrier would need to be able to link the T1s together for inbound calls. This is done through the local telco switch. If the same serving switch (central office) is used to provide the T1s they can be combined to the same route index, which would allow the telco to sieze trunks from either low to high (in order of the trunk members), or high to low, depending on how they do it in your area. The telco will be the glare master, which means if a call outbound and a call inbound attempt to sieze the same trunk the telco wins and the outbound call backs off based on a preset algorithm to attempt completion on a different channel.

If the T1s are serverd from different telco switches you would need to check with them to see if they can extend one to the other's serving switch (this can sometimes be done at additional cost to the customer).

You can create a route group and route list in the CCM cluster that contains both T1s and order them based on which is first in the hunting from the telco end. All users can share the route list, or you can specify overflow.

Remember that telco network timing signals will be sent on the first T1 if they are combined on one route index.

Hope that helps.


New Member

Re: Does SP have PRI T1 virtual bundle service?


I would assume that the route index is a list of route pattern items to point to hardware interface or physical trunk in a priority order on that telco switch:

416-555-[23]XXX ------> Trunk 01 --- Trunk 02

416-555-[45]XXX ------> Trunk 02 --- Trunk 01

I have also got positive feedback from my carrier. But they say it also depends on "portability of numbers, serving CO, extended overflow, etc.".

Thanks a lot. It really helps.


Re: Does SP have PRI T1 virtual bundle service?

The route index in the telco switch is a pointer to the trunk group(s) that serve you. Most service providers can have up to 60 T1/PRIs in a trunk group, depending on the end office type - 5ESS, DMS100/200/500, Ericsson, etc. The DIDs are pointed to the route index which allows completion to your inbound gateways.

LNP can accomodate most 10 digit numbers in a LATA (local access transport area). If you are intraLATA the telco should be able to port your DIDs with little or no trouble. Long distance toll charges are usually the only show stopper, and at 10 miles between your host and remote sites I would not imagine this is an issue for you.

Thanks for the reply. Hope all goes well.


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