[cisco-voip] Transcoding/Conferencing on the same ISDN Gateway

[Rhodium]

Hi Nick,

Thanks for the info. It re-iterates what is stated in the SRND and what I know of CPS.

Quite an interesting fact about how MTP, etc approximately halve the number of calls, I assume simultaneous calls? Didn't think it was that drastic. Any documentation on that or just "experience"?

Regards,

J

--- On Fri, 2/12/10, Nick Matthews <matthnick at gmail.com> wrote:

> From: Nick Matthews <matthnick at gmail.com>
> Subject: Re: [cisco-voip] Transcoding/Conferencing on the same ISDN Gateway
> To: "Rhodium" <rhodium_uk at yahoo.co.uk>
> Cc: "Matthew Saskin" <msaskin at gmail.com>, cisco-voip at puck.nether.net
> Date: Friday, February 12, 2010, 1:42 AM
> FWIW, if you're looking at 5+ CPS
> you're probably looking at an
> AS5X000 box.  Many of the concurrent call numbers that
> are calculated
> for gateways are not done at that high of a call rate
> (implying short
> duration calls).
> 
> Regardless, you can run everything you want on the router
> (VPN, MTP,
> Xcoding, full BGP table) as long as the parameters of the
> equation are
> right.  If you scale your gateway the only problem is
> CPU usage, not
> feature overload.  The only addendum to that is that
> most of these
> numbers are calculated individually, so when you mix and
> match the
> calculations aren't quite as accurate.  Which doesn't
> say much,
> because depending on your call patterns you may get
> different results
> from the posted numbers anyways.  Long calls = better
> for CPU, vad on
> = better for CPU, codec selection = doesn't matter. 
> Most of the
> problem you run into is the pure PPS of these streams
> rather than the
> overhead, which is why MTPs and such can get you higher CPU
> pretty
> quickly.  Xcoding and MTP roughly halve the amount of
> calls you can
> make through the box.
> 
> hth,
> nick
> 
> On Wed, Feb 10, 2010 at 5:21 PM, Rhodium <rhodium_uk at yahoo.co.uk>
> wrote:
> > http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/6x/gateways.html#wp1043594
> >
> > I am referring to CPS and not simultaneous call
> volumes. We have multiple gateways decked with 210 channels
> each (7 x E1) for redundancy and have higher call volumes
> but we are focused on CPS as that brings down the number of
> simultaneous calls on the gateways.
> >
> > Also our BHCA is in the region of 8000 so there is a
> slight difference in type of traffic flow we are seeing.
> >
> > Regards,
> >
> > J
> >
> > --- On Wed, 2/10/10, Matthew Saskin <msaskin at gmail.com>
> wrote:
> >
> >> From: Matthew Saskin <msaskin at gmail.com>
> >> Subject: Re: [cisco-voip] Transcoding/Conferencing
> on the same ISDN Gateway
> >> To: "Rhodium" <rhodium_uk at yahoo.co.uk>
> >> Cc: "Peter Slow" <peter.slow at gmail.com>,
> cisco-voip at puck.nether.net
> >> Date: Wednesday, February 10, 2010, 10:01 PM
> >> Where in the SRND is the call limit
> >> for various gateways listed?  I'd like to take a
> >> look.
> >>
> >> The environment I was referring to was a UCCE
> build
> >> performed by Cisco AS.  4 gateways w/ 10-12 PRI's
> each
> >> handling upwards of 50K calls/day inbound and
> outbound - all
> >> calls were transcoded on these gateways after the
> IVR and
> >> before heading to agents.  During busy hour call
> volumes
> >> weren't above 250 calls/gateway but I'd like to
> see
> >> the reference.
> >>
> >>
> >> Matthew Saskin
> >> msaskin at gmail.com
> >> 203-253-9571
> >>
> >> July 18, 2010 - 1500m swim (in the hudson), 40k
> bike, 10k
> >> run
> >> Please support the Leukemia & Lyphoma Society
> >>
> >> http://pages.teamintraining.org/nyc/nyctri10/msaskin
> >>
> >>
> >>
> >> On Wed, Feb 10, 2010 at 4:53 PM,
> >> Rhodium <rhodium_uk at yahoo.co.uk>
> >> wrote:
> >>
> >> Hi Matthew,
> >>
> >> Appreciate the feedback. I am just concerned that
> as this
> >> is for a call centre, when the number of calls per
> second
> >> (CPS) increases, the number of simultaneous calls
> >> decreases... so I can see a deployment with 1 to 3
> CPS
> >> working with the setup you have described but with
> something
> >> close to around 15 CPS, then according to the
> SRND, that is
> >> a maximum of 255 calls (for a 3845). As we are
> decking out
> >> the ISDN router with 210 channels, then that only
> leaves
> >> headroom for 45 calls not including CPU overhead
> of SCCP,
> >> which led to my mistaken recollection of
> transcoders and
> >> ISDN GWs when it was transcoders and CUBEs.
> >>
> >>
> >> I guess based on the setup I described, the more I
> think
> >> about it, the more I am inclined to make it "off
> >> box". Am I over riding financial judgement with
> caution
> >> too much?
> >>
> >> Regards,
> >>
> >> J
> >>
> >>
> >>
> >> --- On Wed, 2/10/10, Matthew Saskin <msaskin at gmail.com>
> >> wrote:
> >>
> >> > From: Matthew Saskin <msaskin at gmail.com>
> >>
> >> > Subject: Re: [cisco-voip]
> >> Transcoding/Conferencing on the same ISDN Gateway
> >> > To: "Rhodium" <rhodium_uk at yahoo.co.uk>
> >> > Cc: "Peter Slow" <peter.slow at gmail.com>,
> >> cisco-voip at puck.nether.net
> >>
> >> > Date: Wednesday, February 10, 2010, 9:37 PM
> >>
> >>
> >>
> >> > I regularly see single gateways
> >> handle
> >> > all functions (PSTN termination,
> conferencing,
> >> transcoding)
> >> > for sites of all sizes.  I know of nothing
> >> [design-wise]
> >> > preventing you from doing this.  In fact, I
> can think
> >> of
> >>
> >> > some very large installations I've seen that
> were
> >> done
> >> > by advanced services where 3845's were being
> used
> >> to
> >> > terminate 10-12 PRI's plus handle a few
> hundred
> >> > transcoding sessions.
> >>
> >> >
> >> >
> >> > Matthew Saskin
> >> > msaskin at gmail.com
> >> > 203-253-9571
> >> >
> >> > July 18, 2010 - 1500m swim (in the hudson),
> 40k bike,
> >> 10k
> >> > run
> >> > Please support the Leukemia & Lyphoma
> Society
> >>
> >> >
> >> > http://pages.teamintraining.org/nyc/nyctri10/msaskin
> >> >
> >> >
> >> >
> >> > On Wed, Feb 10, 2010 at 4:24 PM,
> >> > Rhodium <rhodium_uk at yahoo.co.uk>
> >>
> >> > wrote:
> >> >
> >> > Hi Peter,
> >> >
> >> > Thank you for your reply.
> >> >
> >> > I dug out a report from Cisco Advanced
> Services that
> >> stated
> >> > that CUBEs should only be used for SIP trunks
> and not
> >> for
> >>
> >> > transcoding/mtp. Knew I read something
> somewhere. Just
> >> not
> >> > the details... :)
> >> >
> >> >
> >> > So we are all definite that for an ISDN GW,
> we can
> >> use
> >> > re-use the DSPs for transcoding in line with
> >> Cisco's
> >>
> >> > recommendations? I want to recommend getting
> a
> >> dedicated
> >> > router for these functions but need to
> justify the
> >> cost so
> >> > if there are no design recommendations, then
> I guess I
> >> can
> >> > just put it all on one box.
> >>
> >> >
> >> >
> >> > Regards,
> >> >
> >> > J
> >> >
> >> >
> >> > --- On Wed, 2/10/10, Peter Slow <peter.slow at gmail.com>
> >> > wrote:
> >> >
> >> > > From: Peter Slow <peter.slow at gmail.com>
> >>
> >> >
> >> > > Subject: Re: [cisco-voip]
> >> Transcoding/Conferencing on
> >> > the same ISDN Gateway
> >> > > To: "Rhodium" <rhodium_uk at yahoo.co.uk>
> >> > > Cc: cisco-voip at puck.nether.net
> >>
> >> >
> >> > > Date: Wednesday, February 10, 2010, 5:02
> PM
> >> >
> >> >
> >> >
> >> > > That is not necessarily correct. It
> >> > > depends heavily on the type of
> >> > > gateway you're talking about, and the
> number
> >> of
> >>
> >> > transcoding
> >> > > or
> >> > > conferencing sessions you might be
> needing.
> >> >
> >> > >
> >> > > -peter
> >> > >
> >> > > On Wed, Feb 10, 2010 at 7:24 AM, Rhodium
> <rhodium_uk at yahoo.co.uk>
> >>
> >> > > wrote:
> >> > > > Hi Experts, :)
> >> > > >
> >> > > > I am sure I read somewhere in a
> design doc
> >> or the
> >> > SRND
> >> >
> >> > > that it is not advocated to put
> transcoding or
> >> > conferencing
> >>
> >> > > resources on a voice gateway handling
> about 150
> >> > calls.
> >> > > >
> >> > > > Am I recalling right or are the old
> brain
> >> cells
> >> > > getting weaker with age.
> >> >
> >> > > >
> >>
> >> > > > If that is correct, a link would
> be
> >> appreciated
> >> > as I
> >> > > can't find it.
> >> > > >
> >> > > > Regards,
> >> > > >
> >> > > > Jason
> >> > > >
> >> > > >
> >>
> >> > > >
> >> > > >
> >> >
> >> > > >
> >> _______________________________________________
> >> > > > cisco-voip mailing list
> >> > > > cisco-voip at puck.nether.net
> >>
> >> > > > https://puck.nether.net/mailman/listinfo/cisco-voip
> >> >
> >> > > >
> >> > >
> >> >
> >> >
> >> >
> >> >
> >>
> >> >
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> >>
> >> >
> >> >
> >> >
> >> >
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> >
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