[VoiceOps] Canadian TF termination

Calvin E. calvine at gmail.com
Fri Jan 23 14:32:37 EST 2015

I thought it worth sharing some feedback from a coworker who has been doing
this a few decades longer than myself:

"First, there’s no such thing as a “Canadian” TFN.  There are NANP TFNs
that can, in theory, be dialed from anywhere in the NANP.  Due to massive
cost differences, NANP telcos allow TFN owners to restrict dialing to
certain areas – 48 states, AK, HI, Canada, USVI/PR, Caribbean, or any
combination thereof.

"Second, it doesn’t matter what the ANI of the calling number is.  What
matters is where the call is dropped into the PSTN.  Thus, if a TFN that is
restricted to Canadian callers only is dialed, and we drop that call off to
one of our US TF Termination vendors, the call will be blocked, as the
first PSTN vendor in the line does an SMS dip, sees this TFN is restricted
to Canada dialers only, sees the call is entering the PSTN in the US, and
rejects it whether the calling number has a Canada NPA or a US NPA."

I hope this helps you find a solution.

--Calvin, a voice services engineer

On Fri, Jan 23, 2015 at 8:38 AM, Ryan Delgrosso <ryandelgrosso at gmail.com>

>  We have trunks with a few canadian providers and route calls from
> canadian source numbers to TF calls exclusively over trunks to canadian
> providers. Usually that solves the issue.
> On 1/22/2015 10:39 AM, Ujjval Karihaloo wrote:
>  Hi All:
>    We are being told by Level3 that if a Canadian DID calls a Canacdian TF
> number, they cannot guarantee call complete and its best effort. Anyone
> else run into something similar?
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