Hi Juan,
Regarding GK separate DP, this is required to apply CAC when calls are initiated from both BR1 & HQ to BR2. As you know CAC won't apply for intra-location. Assume GK has HQ DP, in this case BR1-BR2 calls will have CAC applied, but HQ-BR2 calls won't have CAC (same location). It's always good to have GK in separate DP to have more control over CAC rules between locations. Regarding pass through, I believe you need to keep it. Consider this scenario: HQ is calling BR2 using G729. HQ is having SIP and SCCP phones. As you know, MTP can have one codec. Let's assume that you configured G729r8. Now the problem is CUCM uses g729br8 for SCCP phones and g729r8 for SIP phones (SIP phones don't support annex-b). Without pass-through, calls from SCCP won't have MTP allocated since the codec isn't matching. Please correct me if I am wrong and share your input. Regards, Mohammed Al Baqari From: [email protected] [mailto:[email protected]] On Behalf Of Juan Lopez Sent: Thursday, March 29, 2012 8:26 AM To: George Goglidze Cc: CCIE Study Subject: Re: [OSL | CCIE_Voice] IPexpert lab 10: F/R hub-and-spoke topology vs. RSVP not applied to the GK DP's location Thx George - indeed what I read in SRND about asage of the passthrough. As for the lab (I understand your feedback is general, not lab-specific), there is no sRTP nor video, so my question was why passthrough would be included in the IPExpert solution guides. for the hub_none/RSVP: I'll need to continue searching I think - as indeed it might be a bad idea, but the lab doesn't care for good practices. so for the given topology, I wonder why the ipexpert solutions create a seperate DP for the GK. Anyone out there with some clear thoughts on this? Op 28 maart 2012 23:41 schreef George Goglidze <[email protected]> het volgende: Hi, I'll just write regarding pass-through codec on MTP. You must have pass-through codec when the voice payload is not supported. For example, in case of SRTP traffic, the MTP resource without pass-through codec would not support encryption, but if you use pass-through codec it does not care if the media is encrypted or not, it will just substitute the IP's around in ip header without looking in payload. same goes for video streams using MTP! no pass-through no video, no game :) Now, if it's a good thing in a lab, I guess I'll let you decide :-) It's still good practice in my opinion to always have pass-through as first option. Regarding CAC on hub_none location, bad idea in general, if you need to limit one location just create different location for it. I'm not familiar with the questions, so can't say if you should be limiting that location or not. I guess I'd try NOT to overconfigure. and just do what's asked for. Hope this helps, On Wed, Mar 28, 2012 at 10:36 PM, Juan Lopez <[email protected]> wrote: thx Baktha, I don't see a reason to use the pass-through for the lab purposes either... let's wait and see if someone comes up with some other opinion. for the CAC: well, if the requirement states to have x calls between BR1 and HQ, my guess is that you need to have RSVP applied between BR1 and HQ, and that GK trunk needs to be in the location HQ. If the GK is placed in a seperate DP with a location that has no RSVP with any other locations (like in the ipexpert proctor guide), then calls going from BR1 to CME over GK trunk will not be subject to RSVP cac , although these calls traverse the BR1 link to HQ.. I don't see how the rquirement can be met in that case... cheers, Juan Op 28 maart 2012 19:01 schreef Baktha Muralidharan <[email protected]> het volgende: Hi Juan As for CAC, guess one would have to consider - peak call volume - WAN QoS to decide if location-based CAC is [also] needed. If WAN QoS guarantees enough bandwidth for the anticipated peak volume, then, not sure we need the local-based CAC [RSVP or otherwise] As for pass-through, my experience is you only need the codec that will be used, in this case, the g.729r8. pass-through would be needed if you are plan to do such things as T.38 fax. thanks, /Batkha Message: 3 Date: Wed, 28 Mar 2012 16:33:29 +0200 From: Juan Lopez <[email protected]> To: CCIE Study <[email protected]> Subject: Message-ID: <CANpj6cyy3bDV8OvmNei=yqm5zpvbghxaalvpjyduku1wlqi...@mail.gmail.com <mailto:yqm5zpvbghxaalvpjyduku1wlqib%[email protected]> > Content-Type: text/plain; charset="iso-8859-1" In lab 10A, HQ devices are placed in DP_HQ with location HQ. GK/SIP trunk are placed in seperate DP, with location hub_none and no RSVP applied. So when calling from BR1 phone to CME over GK trunk, no CAC is enforced at the UCM. But the calls go over the FR link, as the FR setup is hub-and-spoke. Considering this topology (versus MPLS) : Shouldn't CAC be enforced (RSVP enabled on the hub_none location) to limit the amount of calls from BR1 to HQ - by extension to CME? I understand GK CAC can be used to contol the amount of calls between the UCM cluster and CME - but in this case we need to have CAC on the link BR1<> HQ too. Also, what is the use of codec pass-through in the RSVP MTP ? Calls use g729 over the WAN (normally) - so what scenario exsits to have codec pass-through configured with g729 as fallback? why not simply use g729r8 as codec, without the passthrough (considering no video is involved here) thx for sharing thoughts! -------------- next part -------------- An HTML attachment was scrubbed... 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