[cisco-voip] CUCM SIP To PSTN

[george.hendrix at l-3com.com]

Basically, I currently have 2 gateways (2x 3925) and each have 4 PRIs (total of 8).  They are located on site with CUCM, so they are configured as MGCP gateways.  However, we are standing up a lot of other sites.  So I am thinking about switching these circuits to 2 10mb SIP circuits.  I would have increased call capacity and I could also work with the Telco to re-route calls destined to remote sites if their SIP circuit goes down to these circuits at the main office.  That's just something not offered with old PRI circuits, or at least no provider I've worked with has offered that with old PRI.  Then if I go with SIP, what's the best configuration in CUCM?  I haven't worked much with SIP circuits, but the ones I have worked with, the gateway was just an h.323 GW in CUCM.  Could it be added as a different type that would register with CUCM or is h.323 the best way to go?

Appreciate any inputs...

Regards,

Bill Hendrix  


-----Original Message-----
From: matthn at gmail.com [mailto:matthn at gmail.com] On Behalf Of Nick Matthews
Sent: Thursday, June 14, 2012 10:17 PM
To: Adel Abushaev
Cc: Hendrix, George (Bill) @ LSG - STRATIS; cisco-voip at puck.nether.net
Subject: Re: [cisco-voip] CUCM SIP To PSTN

The scenario of:
CUCM--SIP--GW--SIP--Provider

The gateway magically turns into a CUBE, and there's a whole bunch of
marketing and technical information on what happens when you do that.

If you compare these two solutions:
-CUCM direct SIP trunk to provider
-Use MTP to keep media to a single IP
-Or use NAT to keep internal addressing safe
or
-Use CUBE

There's a whole bunch of scalability and troubleshooting problems that
can arise from the first. Having a demarcation point at the GW (CUBE)
is extremely helpful. As well, it prevents you from needing to NAT SIP
which historically is a pretty terrible idea.  It also has some SIP
security and flexibility options, and is a good centralization point
for trunks.

I haven't worked with anyone doing the direct trunk from CUCM to
provider. Many providers are going to make their own rules which will
include an SBC (industry term for CUBE).

Short story - just use an SBC. There's about 3-4 compelling reasons.

-nick

On Thu, Jun 14, 2012 at 1:17 PM, Adel Abushaev <adel.abushaev at gmail.com> wrote:
> You can set up a SIP trunk to your SP, assuming that you are a SIP
> client of them.Otherwise, if you want to go over T1, then  you need to
> terminate SIP on the GW to translate between SIP and ISDN PRI or
> whatever other signalling you are using between you and telco.
>
> A.
>
> On Thu, Jun 14, 2012 at 5:44 AM,  <george.hendrix at l-3com.com> wrote:
>> Hi everyone,
>>
>>
>>
>>   I know with h.323 gateways in CUCM, you have to configure dial peers on
>> each gateway and for each CUCM.  Is it possible to create a SIP trunk
>> directly from CUCM to the Telco?  Without having to do any dial peers on the
>> gateway.  Or would it CUCM SIP <> SIP GW <> SIP PSTN, with SIP dial peers on
>> the SIP GW for both CUCM and the PSTN?
>>
>>
>>
>> Thanks,
>>
>>
>>
>> Bill Hendrix
>>
>>
>>
>>
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