Re: polycom Video Unit [7:49882]
- Original Message - From: "Michael L. Williams" To: Sent: Saturday, July 27, 2002 1:38 PM Subject: Re: polycom Video Unit [7:49882] > "John Neiberger" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > I suppose it depends on the unit but ours mainly use unicast to the Cisco > > MCU. As far as I know they use standard H.323. The downside if you're > > using an MCU is that the PolyComm units have a lot of different codecs > > available that might not be known by the MCU. For example, the Cisco MCU > > can only do G.711 audio, but if you let two video units speak directly to > > each other they use G.726 ( I think. Maybe it's G.722?) and it sounds > much > > better. > > That brings up an interesting question tho unless the MCU is converting > between codecs for end stations that might want to use different codecs, > must the MCU "understand" the codec or would it simply act as a relay > startion for that data. (i.e. if two end-stations are using a codec > that they understand but the MCU doesn't, would it be a problem since the > MCU would merely forward the "unknown" (to it) audio data to the other end > station). > > The Cisco MCU supports many more codecs than G.711 including the popular > G.729 codec (which gives roughly G.711 quality with an 8:1 compression). > The G.722 (you were right.. it's G.722, not G.726) that covers from > 50-6900Hz instead of 50-3900Hz as most narrowband codecs do. So if you're > trying to play more high fidelity sound, you may want to use that. I > haven't seen many units that support this codec though (but I have by no > means seen tons of units, just a few). However, if the audio you're > trasmitting is human speech, the G.722 isn't going to gain you much in terms > of sound quality since it would be preserving an additional frequency range > that's not used alot by human speech. > > Does anyone have any input or experience with how and/or when the MCU codec > support comes into play? I would think that if the endpoints are at the > same datarate and using the same audio/video codecs, the MCU would just be a > bounce point and the actual codecs in the MCU wouldn't be utilized Just > a theory tho.. > > Mike W. > > > You pose a good question about the MCU. I'm not very experienced with H.323, gatekeepers, and such so I can't answer that. I know just enough to be hazardous. Regarding the G.722, it sounds noticably better than G.711, as witnessed by a couple of senior Cisco engineers who wanted to witness that (plus a few other issues) for themselves. They swore that G.711 should sound just fine, but compared to G.722 it sounds like someone placed a pillow over the speaker and it's more difficult to distinguish certain syllables. John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49983&t=49882 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: polycom Video Unit [7:49882]
The Polycom Viewstations and Via-Video units use unicast UDP (RTP) traffic for data streams and unicast TCP(RTCP) traffic for signaling and control. Part of the initialization process is an agreement on what codec's are going to be used. This negotiation process is different depending on if there is a gatekeeper involved in the conversation. The important thing to remember about a 323 MCU is that it is essentially a h.323 terminal. Any I-frames or K-frames that happen between a terminal and the MCU are between the terminal and the MCU - not between participants in the conference. There is an initialization process between each endpoint and the MCU that would handle things like data rate and terminal capabilities. I would refer you to a handful of whitepapers available on polycom's web site, especially the ones from PictureTel. http://www.polycom.com/resource_center/0,1408,997,00.html The old pictureTel whitepapers are much better written and easier to use than anything else I've found on h.323 so far. There is another excellent resource on the web/mail-list; the h323 forum. I don't recall the web site right now, do a google search I'm sure you will hit. TTFN, Bill 'VTC over IPSec' Pearch, Anchorage AK -Original Message- From: Michael L. Williams [mailto:[EMAIL PROTECTED]] Sent: Saturday, July 27, 2002 11:39 AM To: [EMAIL PROTECTED] Subject: Re: polycom Video Unit [7:49882] "John Neiberger" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I suppose it depends on the unit but ours mainly use unicast to the > Cisco MCU. As far as I know they use standard H.323. The downside if > you're using an MCU is that the PolyComm units have a lot of different > codecs available that might not be known by the MCU. For example, the > Cisco MCU can only do G.711 audio, but if you let two video units > speak directly to each other they use G.726 ( I think. Maybe it's > G.722?) and it sounds much > better. That brings up an interesting question tho unless the MCU is converting between codecs for end stations that might want to use different codecs, must the MCU "understand" the codec or would it simply act as a relay startion for that data. (i.e. if two end-stations are using a codec that they understand but the MCU doesn't, would it be a problem since the MCU would merely forward the "unknown" (to it) audio data to the other end station). The Cisco MCU supports many more codecs than G.711 including the popular G.729 codec (which gives roughly G.711 quality with an 8:1 compression). The G.722 (you were right.. it's G.722, not G.726) that covers from 50-6900Hz instead of 50-3900Hz as most narrowband codecs do. So if you're trying to play more high fidelity sound, you may want to use that. I haven't seen many units that support this codec though (but I have by no means seen tons of units, just a few). However, if the audio you're trasmitting is human speech, the G.722 isn't going to gain you much in terms of sound quality since it would be preserving an additional frequency range that's not used alot by human speech. Does anyone have any input or experience with how and/or when the MCU codec support comes into play? I would think that if the endpoints are at the same datarate and using the same audio/video codecs, the MCU would just be a bounce point and the actual codecs in the MCU wouldn't be utilized Just a theory tho.. Mike W. [GroupStudy.com removed an attachment of type application/x-pkcs7-signature which had a name of smime.p7s] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49917&t=49882 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: polycom Video Unit [7:49882]
"John Neiberger" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I suppose it depends on the unit but ours mainly use unicast to the Cisco > MCU. As far as I know they use standard H.323. The downside if you're > using an MCU is that the PolyComm units have a lot of different codecs > available that might not be known by the MCU. For example, the Cisco MCU > can only do G.711 audio, but if you let two video units speak directly to > each other they use G.726 ( I think. Maybe it's G.722?) and it sounds much > better. That brings up an interesting question tho unless the MCU is converting between codecs for end stations that might want to use different codecs, must the MCU "understand" the codec or would it simply act as a relay startion for that data. (i.e. if two end-stations are using a codec that they understand but the MCU doesn't, would it be a problem since the MCU would merely forward the "unknown" (to it) audio data to the other end station). The Cisco MCU supports many more codecs than G.711 including the popular G.729 codec (which gives roughly G.711 quality with an 8:1 compression). The G.722 (you were right.. it's G.722, not G.726) that covers from 50-6900Hz instead of 50-3900Hz as most narrowband codecs do. So if you're trying to play more high fidelity sound, you may want to use that. I haven't seen many units that support this codec though (but I have by no means seen tons of units, just a few). However, if the audio you're trasmitting is human speech, the G.722 isn't going to gain you much in terms of sound quality since it would be preserving an additional frequency range that's not used alot by human speech. Does anyone have any input or experience with how and/or when the MCU codec support comes into play? I would think that if the endpoints are at the same datarate and using the same audio/video codecs, the MCU would just be a bounce point and the actual codecs in the MCU wouldn't be utilized Just a theory tho.. Mike W. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49900&t=49882 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: polycom Video Unit [7:49882]
It is not sending the URL. Go to Cisco.com and do a search on Polycom Video First link http://www.cisco.com/warp/public/788/voip/polycom_video_over_ip.html ""Ronnie Higginbotham"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > ""Ronnie Higginbotham"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Watch for word wrap > > > > Ronnie > > > > > > > > ""Michael L. Williams"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Depends on the model, but usually you'll see traffic all into either > > > 128Kbps, 384kbps, 768Kbps or 1.5Mbps We have a Polycom unit that > has > > > ISDN and a LAN port, but if you telnet to it's IP on the LAN you get a > > > "status" page showing H.323 is disabled, so we can't use it on the LAN > (at > > > least without a software update or something). But if you Polycam can > > video > > > conference over IP with it's ethernet port, then it should be standard > > > H.323. I can't recall the ports right off the top of my head, but I'm > > > thinking somewhere in the 2600+ range (I've seen other units that use > > > 2000-2063), but don't quote me on that It's regular IP unicast > > traffic, > > > but (depending on the model) it's possible to do a multicast streaming > > > presentation (usually you'll use the multicast when you want to > broadcast > > a > > > presentation or video, etc to many viewer but most times you're not > in > > a > > > "conference" where there are many senders and receivers) > > > > > > HTH, > > > Mike > > > > > > "Steven A. Ridder" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > Does anyone know what type of traffic a typical Polycom Video Con. > unit > > > > creates? It it multicast? What ports does it use? Is it standard > > h.323? > > > > > > > > I can sniff it, but if anyone has already done their homework on it, > it > > > will > > > > save me some time. > > > > > > > > -- > > > > > > > > RFC 1149 Compliant. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49898&t=49882 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: polycom Video Unit [7:49882]
""Ronnie Higginbotham"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Watch for word wrap > > Ronnie > > > > ""Michael L. Williams"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Depends on the model, but usually you'll see traffic all into either > > 128Kbps, 384kbps, 768Kbps or 1.5Mbps We have a Polycom unit that has > > ISDN and a LAN port, but if you telnet to it's IP on the LAN you get a > > "status" page showing H.323 is disabled, so we can't use it on the LAN (at > > least without a software update or something). But if you Polycam can > video > > conference over IP with it's ethernet port, then it should be standard > > H.323. I can't recall the ports right off the top of my head, but I'm > > thinking somewhere in the 2600+ range (I've seen other units that use > > 2000-2063), but don't quote me on that It's regular IP unicast > traffic, > > but (depending on the model) it's possible to do a multicast streaming > > presentation (usually you'll use the multicast when you want to broadcast > a > > presentation or video, etc to many viewer but most times you're not in > a > > "conference" where there are many senders and receivers) > > > > HTH, > > Mike > > > > "Steven A. Ridder" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Does anyone know what type of traffic a typical Polycom Video Con. unit > > > creates? It it multicast? What ports does it use? Is it standard > h.323? > > > > > > I can sniff it, but if anyone has already done their homework on it, it > > will > > > save me some time. > > > > > > -- > > > > > > RFC 1149 Compliant. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49897&t=49882 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: polycom Video Unit [7:49882]
Watch for word wrap Ronnie ""Michael L. Williams"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Depends on the model, but usually you'll see traffic all into either > 128Kbps, 384kbps, 768Kbps or 1.5Mbps We have a Polycom unit that has > ISDN and a LAN port, but if you telnet to it's IP on the LAN you get a > "status" page showing H.323 is disabled, so we can't use it on the LAN (at > least without a software update or something). But if you Polycam can video > conference over IP with it's ethernet port, then it should be standard > H.323. I can't recall the ports right off the top of my head, but I'm > thinking somewhere in the 2600+ range (I've seen other units that use > 2000-2063), but don't quote me on that It's regular IP unicast traffic, > but (depending on the model) it's possible to do a multicast streaming > presentation (usually you'll use the multicast when you want to broadcast a > presentation or video, etc to many viewer but most times you're not in a > "conference" where there are many senders and receivers) > > HTH, > Mike > > "Steven A. Ridder" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Does anyone know what type of traffic a typical Polycom Video Con. unit > > creates? It it multicast? What ports does it use? Is it standard h.323? > > > > I can sniff it, but if anyone has already done their homework on it, it > will > > save me some time. > > > > -- > > > > RFC 1149 Compliant. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49896&t=49882 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: polycom Video Unit [7:49882]
Depends on the model, but usually you'll see traffic all into either 128Kbps, 384kbps, 768Kbps or 1.5Mbps We have a Polycom unit that has ISDN and a LAN port, but if you telnet to it's IP on the LAN you get a "status" page showing H.323 is disabled, so we can't use it on the LAN (at least without a software update or something). But if you Polycam can video conference over IP with it's ethernet port, then it should be standard H.323. I can't recall the ports right off the top of my head, but I'm thinking somewhere in the 2600+ range (I've seen other units that use 2000-2063), but don't quote me on that It's regular IP unicast traffic, but (depending on the model) it's possible to do a multicast streaming presentation (usually you'll use the multicast when you want to broadcast a presentation or video, etc to many viewer but most times you're not in a "conference" where there are many senders and receivers) HTH, Mike "Steven A. Ridder" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Does anyone know what type of traffic a typical Polycom Video Con. unit > creates? It it multicast? What ports does it use? Is it standard h.323? > > I can sniff it, but if anyone has already done their homework on it, it will > save me some time. > > -- > > RFC 1149 Compliant. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49887&t=49882 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: polycom Video Unit [7:49882]
- Original Message - From: "Steven A. Ridder" To: Sent: Saturday, July 27, 2002 10:05 AM Subject: polycom Video Unit [7:49882] > Does anyone know what type of traffic a typical Polycom Video Con. unit > creates? It it multicast? What ports does it use? Is it standard h.323? > > I can sniff it, but if anyone has already done their homework on it, it will > save me some time. > > -- > > RFC 1149 Compliant. > I suppose it depends on the unit but ours mainly use unicast to the Cisco MCU. As far as I know they use standard H.323. The downside if you're using an MCU is that the PolyComm units have a lot of different codecs available that might not be known by the MCU. For example, the Cisco MCU can only do G.711 audio, but if you let two video units speak directly to each other they use G.726 ( I think. Maybe it's G.722?) and it sounds much better. John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49885&t=49882 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
