The reason I think that RTP is not being sent directly between the phones is because the instances of sound degradation are reproduced whenever my vmware CUCM test cluster's processor spikes. An odd coincidence. The cluster's performance shouldn't have any bearing after RTP stream communication is started unless it is part of the call flow via software MTP termination.
Anyway, admittedly, this is a weak way to make a determination - the best thing to do is start a call between the clusters and review the MTP stats as the call is taking place, as you said. Even so, if I remove software MTP from the test cluster's MRG for the ICT device pool, I should be losing the ability to transfer and place calls on hold across the cluster from the test cluster's side. Like I said, I tried it and it still seemed to work. I can accept a dynamic MTP allocation as a plausible explanation, but removing the software MTP on one side entirely and still not impacting hold and trasfer features across clusters tells me that I'm misunderstanding the context in which MTPs are being used. On Thu, Oct 15, 2009 at 9:46 AM, Vik Malhi <vma...@ipexpert.com> wrote: > As well as supporting gateways that don’t support h245 tcs, MTP is also > used when DTMF capabilities cannot be negotiated. In this release of CUCM > MTP can be dynamically allocated. Establish an active call and check the > performance counters (SW MTP) to make certain it is not being used on either > cluster. > > How are you certain the endpoints are not talking directly with each other? > I would expect the call signaling ip address to be the CUCM but the > MediaIP’s to be the endpoints (or MTP). > -- > Vik Malhi – CCIE #13890 > Senior Technical Instructor - IPexpert, Inc. > > Telephone: +1.810.326.1444 > Fax: +1.810.454.0130 > Mailto: *vma...@ipexpert.com > > * > Join our free online support and peer group communities: > *http://www.IPexpert.com/communities <http://www.ipexpert.com/communities> > *IPexpert - The Global Leader in Self-Study, Classroom-Based, > Video-On-Demand and Audio Certification Training Tools for the Cisco CCIE > R&S Lab, CCIE Security Lab, CCIE Service Provider Lab , CCIE Voice Lab and > CCIE Storage Lab Certifications. > > > > > > > > ------------------------------ > *From: *Nara Shikamaru <shikam...@kagadis.com> > *Date: *Thu, 15 Oct 2009 09:28:13 -0700 > *To: *Vik Malhi <vma...@ipexpert.com> > *Cc: *OSL Group <ccie_voice@onlinestudylist.com> > *Subject: *Re: [OSL | CCIE_Voice] Call flow for intercluster trunks > > Vik, > MTP is not being used for the ICTs on either side. However, the check > box on the ICT *Media Termination Point Required* may not be checked, but > does that mean that if it's not checked it will certainly not be used? My > big question is that, according the the CUCM help for this page, MTP is used > in order to provide for call transfer and hold features across the > clusters. As it says; > > Media Termination Point Required This check box is used to indicate whether > a media termination point (MTP) is used to implement features that H.323 > does not support (such as hold and transfer). Check the Media Termination > Point Required check box if you want to use a media termination point to > implement features. Uncheck the Media Termination Point Required check box > if you do not want to use a media termination point to implement features. > Use this check box only for H.323 clients and those H.323 devices that do > not support the H.245 Empty Capabilities Set or if you want media streaming > to terminate through a single source. If you check this check box to require > an MTP and one or both parties are a video endpoint, the call operates as > audio only. > > So, right now the check box is not checked on either side and the hold and > transfer still continue to work in both directions. Furthermore, I've > removed the software MTP from the test cluster's MRG. Still works. Am I > understanding the purpose of the MTP in this context? > > On Wed, Oct 14, 2009 at 8:28 PM, Vik Malhi <vma...@ipexpert.com> wrote: > > The call flow should be between endpoints. UNLESS MTP is being used. > Software MTP usage is the most likely cause of your voice degradation. > Uncheck MTP if you have it marked on the ICT. > -- > Vik Malhi – CCIE #13890 > Senior Technical Instructor - IPexpert, Inc. > > Telephone: +1.810.326.1444 > Fax: +1.810.454.0130 > Mailto: *vma...@ipexpert.com <http://vma...@ipexpert.com/> > > * > Join our free online support and peer group communities: > *http://www.IPexpert.com/communities <http://www.ipexpert.com/communities> > *IPexpert - The Global Leader in Self-Study, Classroom-Based, > Video-On-Demand and Audio Certification Training Tools for the Cisco CCIE > R&S Lab, CCIE Security Lab, CCIE Service Provider Lab , CCIE Voice Lab and > CCIE Storage Lab Certifications. > > > > > > > > ------------------------------ > *From: *Nara Shikamaru <shikam...@kagadis.com < > http://shikam...@kagadis.com/> > > *Date: *Wed, 14 Oct 2009 13:55:47 -0700 > *To: *OSL Group <ccie_voice@onlinestudylist.com < > http://ccie_voice@onlinestudylist.com/> > > *Subject: *[OSL | CCIE_Voice] Call flow for intercluster trunks > > > I've joined two clusters together (for a migration at work, not for lab > obviously) and would like to know if anyone has an answer to a question I > have. In a normal call in a single cluster, two phones send the rtp streams > to each other until they hang up. If a phone makes an offnet call, the two > endpoints are the phone and the gateway that terminates the PRI. I'm having > trouble (for whatever reason) finding explicit detail on the call flow of a > call involving an non-gatekeeper controlled intercluster trunk. My > impression is that the CUCM clusters are involved as endpoints in the rtp > stream, and the reason I think that is because I've noticed severe call > quality degredation when the CUCM servers are stressed (I'm running the test > on vmware, so the effects are pronounced and easy to duplicate.) > > Can someone let me know if I'm understanding the call flow correctly? > > -- > -Shikamaru > > ------------------------------ > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com <http://www.ipexpert.com/> > > > > > -- > -Shikamaru > > -- -Shikamaru
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