Mailing List Archive: CER for Europe... variable length dial plan and PSAP callback

CER for Europe... variable length dial plan and PSAP callback

Feb 2, 2022, 8:11 AM

Post #1 of 3 (355 views)

We currently have offices throughout Western Europe and each site currently
has a PRI/T1-CAS/Analog nightmare...

We are implementing centralized SIP (ATT) out of London and we need to make
sure 112/999 calls get directed to the proper nation's PSAP.

We would also like to support callback.

So, we spun up a CER cluster in Europe...

First thing we found, CER only supports one entry point (so, we picked 112,
and translate 999 in the UK to 112 and match an ERL that changes this back
to 999 and tags a UK DID). This seems to work fine (albeit clunkily).

The real problem is call back...

CER also only supports one entry point for callback.... the problem is we
have a variable length dial plan with + then 10, 11, 12 and 13 digits (each
with 2 digit country codes).

So, how do we do callback?

First idea was to pay digits on the end in CER, strip them off on the
outbound via SIP and then pad them back in on the inbound back to CER to
route them to the station.

Is this crazy?

Thanks!

Jonathan

Re: CER for Europe... variable length dial plan and PSAP callback [ In reply to ]

bmeade90 at vt

Feb 4, 2022, 12:46 PM

Post #2 of 3 (351 views)

Permalink

For the callback, maybe just use translation patterns for each callback
number to go to a fixed-length number that matches the CTI RP for callback.

You could make dummy numbers like:
9131000
9131001

Then your ELIN would need to match in CER too to be 1000/1001 but you can
hard set the actual ELIN on your outbound route patterns.

It makes exporting PS-ALI info from CER not work but I don't see that used
much anyways.

On Wed, Feb 2, 2022 at 11:13 AM Jonathan Charles <jonvoip@gmail.com> wrote:

> We currently have offices throughout Western Europe and each site
> currently has a PRI/T1-CAS/Analog nightmare...
>
> We are implementing centralized SIP (ATT) out of London and we need to
> make sure 112/999 calls get directed to the proper nation's PSAP.
>
> We would also like to support callback.
>
> So, we spun up a CER cluster in Europe...
>
> First thing we found, CER only supports one entry point (so, we picked
> 112, and translate 999 in the UK to 112 and match an ERL that changes this
> back to 999 and tags a UK DID). This seems to work fine (albeit clunkily).
>
> The real problem is call back...
>
> CER also only supports one entry point for callback.... the problem is we
> have a variable length dial plan with + then 10, 11, 12 and 13 digits (each
> with 2 digit country codes).
>
>
> So, how do we do callback?
>
> First idea was to pay digits on the end in CER, strip them off on the
> outbound via SIP and then pad them back in on the inbound back to CER to
> route them to the station.
>
> Is this crazy?
>
>
> Thanks!
>
>
> Jonathan
>
> _______________________________________________
> cisco-voip mailing list
> cisco-voip@puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-voip
>

Re: CER for Europe... variable length dial plan and PSAP callback [ In reply to ]

jonvoip at gmail

Feb 14, 2022, 1:04 PM

Post #3 of 3 (346 views)

Permalink

What I ended up doing was padding the numbers in CER (with two trailing
zeros), then stripping them off on the gateway and then translating them
back on for callback... it works... so I guess I can't complain, but it
looks inelegant.

On Fri, Feb 4, 2022 at 2:46 PM Brian Meade <bmeade90@vt.edu> wrote:

> For the callback, maybe just use translation patterns for each callback
> number to go to a fixed-length number that matches the CTI RP for callback.
>
> You could make dummy numbers like:
> 9131000
> 9131001
>
> Then your ELIN would need to match in CER too to be 1000/1001 but you can
> hard set the actual ELIN on your outbound route patterns.
>
> It makes exporting PS-ALI info from CER not work but I don't see that used
> much anyways.
>
> On Wed, Feb 2, 2022 at 11:13 AM Jonathan Charles <jonvoip@gmail.com>
> wrote:
>
>> We currently have offices throughout Western Europe and each site
>> currently has a PRI/T1-CAS/Analog nightmare...
>>
>> We are implementing centralized SIP (ATT) out of London and we need to
>> make sure 112/999 calls get directed to the proper nation's PSAP.
>>
>> We would also like to support callback.
>>
>> So, we spun up a CER cluster in Europe...
>>
>> First thing we found, CER only supports one entry point (so, we picked
>> 112, and translate 999 in the UK to 112 and match an ERL that changes this
>> back to 999 and tags a UK DID). This seems to work fine (albeit clunkily).
>>
>> The real problem is call back...
>>
>> CER also only supports one entry point for callback.... the problem is we
>> have a variable length dial plan with + then 10, 11, 12 and 13 digits (each
>> with 2 digit country codes).
>>
>>
>> So, how do we do callback?
>>
>> First idea was to pay digits on the end in CER, strip them off on the
>> outbound via SIP and then pad them back in on the inbound back to CER to
>> route them to the station.
>>
>> Is this crazy?
>>
>>
>> Thanks!
>>
>>
>> Jonathan
>>
>> _______________________________________________
>> cisco-voip mailing list
>> cisco-voip@puck.nether.net
>> https://puck.nether.net/mailman/listinfo/cisco-voip
>>
>