SIP Trunk Choice

[libellis]

For a new 3300ICP installation involving two sites (600 stations and 150 stations - both sites located in the metropolitan area of a major city), is it time to fully scrap PRI's and go with all SIP trunks from the Carriers, or is that not yet a wise approach if the intention is to be a bit on the conservative side?

Is it more prudent to use a mixed approach (e.g. PRI's for inbound and a mixture for outbound)? While cost is important, it's not the main driver, reliability and supported features are, including the ability to get problems resolved by the Carrier.

 

[nytalkin]

Our experiences have followed the historical ability of the various carriers. If a carrier wasn't responsive or reliable in the TDM solution the same has been true Global and Paetec. Not so much help from One Communications and TW.

Not to say every deployment of SIP has been without problems, but some carriers are better at solving problems and keeping us in the loop.

NO GOOD DEED GOES UNPUNISHED!

 

[james1982]

We have been to discuss with many SIP providers and they themselves advised us to have a mixture of the 2 - SIP and ISDN30.

Why risk putting your eggs in one basket?

 

[libellis]

Thanks for the guidance. The concerns were about problem resolution with the Carriers, and that can be difficult even under the best of circumstances, and even with the best of Carriers.

 

[Supernova99]

ISDN30 is generally very reliable easy to setup and compatible as it adheres to a regulated set of standards.

SIP on the other hand can be tricky to setup and can be troublesome as it is an open standard different carriers invoke different features and you may find that some things do not work as expected.
Make sure that whoever you are looking to provide SIP trunks has passed the Mitel Interop testing (can be located on the MoL Knowledge base)
The Interop test will also highlight any thing that is and is not supported.

Share what you know - Learn what you don't

 

[libellis]

Thanks. We're aware of the compatibility issues and that the SIP trunks must have passed interoperability testing. Aside from cost savings, are there currently compelling features that should factor into the decision.

 

[Supernova99]

SIP trunks are more flexible as they can be hosted anywhere in the world.
Also in terms of resiliency if you have a resilient system in a data centre in a different part of the country or world your trunks will still provide the same DID functionality.
Whereas ISDN30 trunks can only have the same DID if they are located in the same area.

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