[cisco-voip] ISR G2 PVDM3 DSPs on backplane

[Nick Matthews]

I've seen this dozens of times.  Most people probably don't even
realize they have a problem.  Some may even have two providers that
have managed to be on the same clocking domain.  I've even seen some
people with providers that were willing to be the slave because the
provider is SIP on the other side of the router.

The only way to provide two different voice clocking domains is by
having two separate groups of DSPs - this means HDV cards.

If you have one PRI for failover or that is not used until the first
is filled, you can probably get away with slips.  The basic rule I've
gone by is:  if you don't need to fax or modem over the T1, you're
probably alright with slips if it's not your primary line.  There are
chances for voice quality, it all depends.  It could be a cell-phone
like quality issue you probably won't notice, or distinct chirps on
the line that can be annoying.

-nick

On Mon, Jun 28, 2010 at 8:38 PM, Bill Riley <bill at hitechconnection.net> wrote:
> I am not concerned with what works, and more concerned with what is the best
> solution.
>
>
>
> From: Jason Aarons (US) [mailto:jason.aarons at us.didata.com]
> Sent: Monday, June 28, 2010 5:25 PM
> To: Jim Reed; Bill; Beck, Christopher; cisco-voip
> Subject: RE: [cisco-voip] ISR G2 PVDM3 DSPs on backplane
>
>
>
> While it’s working, from a solution design standpoint I’m being told that if
> the timing varies from the providers it could result in problems, so design
> preference should be to have separate routers in this scenario.
>
>
>
> I’m with you, I’ve done it before and it did work, and I’d hate to explain
> it to customer they need another router if the clocks are far apart.
>
>
>
> From: Jim Reed [mailto:jreed at swiftnews.com]
> Sent: Monday, June 28, 2010 6:09 PM
> To: Bill; Beck, Christopher; Jason Aarons (US); cisco-voip
> Subject: Re: [cisco-voip] ISR G2 PVDM3 DSPs on backplane
>
>
>
> I am currently using PRIs from different vendors — AT&T and Integra — on the
> same router.  Two (2) separate VWICs on the same 2851.  VWIC2-1MFT-T1/E1.
>  No problems with voice quality, errors, etc.  Configured as follows:
> network-clock-participate wic 0
> network-clock-participate wic 1
> network-clock-select 1 T1 0/0/0
> Just thought I’d pass it along.
> --
> Jim Reed
> Manager of Technical Services
> Swift Communications, Inc.
> 970-384-9141 (Direct)
> 775-772-7666 (Cell)
> Sorry, no faxes accepted.
> Please send documents by eMail.
>
>
>
> On 6/28/10 3:44 PM, "Bill" <bill at hitechconnection.net> wrote:
>
> Are you sure that is the case currently? I think you can have multiple PRI’s
> inside the same router on an ISR but they can not be on the same VWIC.
>
> Jason said you can not have multiple PRI’s within the same router.
>
>
> ________________________________
>
> From: Beck, Christopher [mailto:CBeck at usg.com]
> Sent: Monday, June 28, 2010 4:40 PM
> To: Bill; 'Jason Aarons (US)'; 'cisco-voip'
> Subject: RE: [cisco-voip] ISR G2 PVDM3 DSPs on backplane
>
> This is true on the 2800/3800 today (except in the case of the NM-NDV
> modules mentioned, but I don’t think so even in that case).  It is because
> there is a “single” PLL clocking circuit shared for all PRI’s.  The WIC must
> be configured to participate in that clocking circuit prior to setting up
> the PRI.   I can’t remember  any device that could handle this in 20 years
> of installing channel banks, muxes, routers, etc.
>
> That said, a lot of times it will work acceptably because the clocks are
> close enough, especially if the local loop provider is the same on all
> links.  But, you have to test it to know in any case.
>
>
>
> -Chris
>
>
> From: cisco-voip-bounces at puck.nether.net
> [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Bill
> Sent: Monday, June 28, 2010 4:21 PM
> To: 'Jason Aarons (US)'; 'cisco-voip'
> Subject: Re: [cisco-voip] ISR G2 PVDM3 DSPs on backplane
>
> What? I know you could not do different Telco’s on the same two port card
> but you can’t do two telco’s in the same router? Is there an official
> response to this? Is there a specific defect I can reference with my Cisco
> AM?
>
>
> ________________________________
>
> From: cisco-voip-bounces at puck.nether.net
> [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Jason Aarons (US)
> Sent: Monday, June 28, 2010 4:12 PM
> To: cisco-voip (cisco-voip at puck.nether.net)
> Subject: [cisco-voip] ISR G2 PVDM3 DSPs on backplane
>
> A TAC engineer at Cisco Live confirmed you can’t have multiple voice PRIs
> from separate telcos come into a G2 with different clocks. For example you
> have a AT&T PRI, a Verizon PRI, a Century Link PRI, a Alltell PRI, a Paetec
> PRI all in the same router. You can’t clock the backplane to  more than one
> source!  You’ll get slips, etc audio will sound bad, faxes/modems will fail.
>  Fix is separate routers.  He said he thought a 2800 with DSPs on a NM-HDV
> module would work though.  My exact question was can you carve up the
> backplane PVDM3 clocking for separate PRIs somehow.
>
> ________________________________
>
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