RE: Multimedia/Voice over VSAT [7:71706]
Hello Pieter, As you know delay is one of the problems with VSAT. You can do nothing about hops to the satellite and back. What you need is some prioritization/QoS in your network for the voice traffic. There are various ways to do this. I don't have personal experience with AutoQoS but it's a new feature supported on the Cisco routers and switches - check it out: (you may need a CCO login) http://www.cisco.com/en/US/partner/tech/tk543/tk759/tk879/tech_protoco l_home.html My other suggestion is for if you want to get into the details to configure your equipment manually, is to have a look at the QDM (QoS Device Manager). This is a web based tool that is free from Cisco's website. http://www.cisco.com/en/US/partner/products/sw/netmgtsw/ps2063/index.h tml And then my final suggestion is to have a look at RSVP (Resource Reservation Protocol). This protocol will reserve bandwith for your application along the transmission path. Regards, Janó PS. Nice to see fellow SAfricans on the forum. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71723&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Multimedia/Voice over VSAT [7:71706]
- jvd wrote: jvd, it's nice to have you on the list. It looks like you post using the Web site. A lot of people do GroupStudy via e-mail. They can't tell what your messages refer to. They seem like orphans. When posting from the Web, please press the Quote button first and then add comments, and your messages will arrive with some context. Thanks. > > Hello Pieter, > > As you know delay is one of the problems with VSAT. You can do > nothing about hops to the satellite and back. What you need is > some prioritization/QoS in your network for the voice traffic. > There are various ways to do this. But is prioritization and QoS even worthy bothering with for traffic going to a satellite? Wouldn't that be sort of like priorizing which bus leaves the New York bus station first to avoid delay going to San Francisco? The few minutes saved by letting the San Fran bus leave before the Philadelphia bus are completely irrelvant compared the many days it takes to get to San Fran. On routers, the few nanoseconds saved by outputting voice first are irrelvant compared to the hundreds of milliseconds to reach the satellite. > > I don't have personal experience with AutoQoS but it's a new > feature supported on the Cisco routers and switches - check it > out: (you may need a CCO login) > http://www.cisco.com/en/US/partner/tech/tk543/tk759/tk879/tech_protoco > l_home.html > > My other suggestion is for if you want to get into the details > to configure your equipment manually, is to have a look at the > QDM (QoS Device Manager). This is a web based tool that is free > from Cisco's website. > http://www.cisco.com/en/US/partner/products/sw/netmgtsw/ps2063/index.h > tml > > And then my final suggestion is to have a look at RSVP > (Resource Reservation Protocol). This protocol will reserve > bandwith for your application along the transmission path. > > Regards, > Janó > > PS. Nice to see fellow SAfricans on the forum. I thought you were from Brazil?! Now I am curious! :-) Priscilla > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71754&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Multimedia/Voice over VSAT [7:71706]
Priscilla Oppenheimer wrote: > > It looks like you post using the Web site. A lot of people do > GroupStudy via e-mail. They can't tell what your messages refer > to. They seem like orphans. When posting from the Web, please > press the Quote button first and then add comments, and your > messages will arrive with some context. Thanks. > Yeah I picked up the topic today about people getting all GRUMPY because some of us don't quote first. The Web site has two options to view the messages: Flat and Threaded View. In flat view you don't have the Quote Button. :( I changed to Threaded View so I could quote, specially for you... (and the other thousand happy people out there). No serious, I didn't know about this problem until today. > > On routers, the few nanoseconds saved by outputting voice first > are irrelvant compared to the hundreds of milliseconds to reach > the satellite. > Yes maybe, but won't you run into trouble with jitter? And then also I think that if you don't have some kind of prioritization/fragmentation to take care of big data packets you can also have a problem with smaller sized voice packets. I'm thinking here in the line of FRF.12 (fragmentation for voice on frame-relay networks). I don't know what's a similar technique for satellite networks... > > > > > PS. Nice to see fellow SAfricans on the forum. > > I thought you were from Brazil?! Now I am curious! :-) > I'm posting from sunny Brazil, that's right! I met a Brazlian girl in SA and made the big decision to move to Brazil, learn a new language, and the rest is history. Kind regards, Janó Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71759&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Multimedia/Voice over VSAT [7:71706]
I can only comment about voice over VSAT. The propagation delay which could be anything from 600ms to 1200ms (depending on the VSAT configuration) makes the voice calls sound like long-distance international calls. So the users have to be aware of the "you-talk-then-i-talk" phenomenon. As for the asymmetrical path, that should really not be a problem, you should just ensure that your routing protocol is aware that the VSAT path consists on two simplex links connected to 2 different ports. I am assuming here that your VSAT uses a DVB-IP receiver for downlink traffic and an SCPC modem for uplink traffic. George Murage - jvd wrote: jvd, it's nice to have you on the list. It looks like you post using the Web site. A lot of people do GroupStudy via e-mail. They can't tell what your messages refer to. They seem like orphans. When posting from the Web, please press the Quote button first and then add comments, and your messages will arrive with some context. Thanks. > > Hello Pieter, > > As you know delay is one of the problems with VSAT. You can do > nothing about hops to the satellite and back. What you need is > some prioritization/QoS in your network for the voice traffic. > There are various ways to do this. But is prioritization and QoS even worthy bothering with for traffic going to a satellite? Wouldn't that be sort of like priorizing which bus leaves the New York bus station first to avoid delay going to San Francisco? The few minutes saved by letting the San Fran bus leave before the Philadelphia bus are completely irrelvant compared the many days it takes to get to San Fran. On routers, the few nanoseconds saved by outputting voice first are irrelvant compared to the hundreds of milliseconds to reach the satellite. > > I don't have personal experience with AutoQoS but it's a new > feature supported on the Cisco routers and switches - check it > out: (you may need a CCO login) > http://www.cisco.com/en/US/partner/tech/tk543/tk759/tk879/tech_protoco > l_home.html > > My other suggestion is for if you want to get into the details > to configure your equipment manually, is to have a look at the > QDM (QoS Device Manager). This is a web based tool that is free > from Cisco's website. > http://www.cisco.com/en/US/partner/products/sw/netmgtsw/ps2063/index.h > tml > > And then my final suggestion is to have a look at RSVP > (Resource Reservation Protocol). This protocol will reserve > bandwith for your application along the transmission path. > > Regards, > Jans > > PS. Nice to see fellow SAfricans on the forum. I thought you were from Brazil?! Now I am curious! :-) Priscilla Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71773&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Multimedia/Voice over VSAT [7:71706]
I can only comment about voice over VSAT. The propagation delay which could be anything from 600ms to 1200ms (depending on the VSAT configuration) makes the voice calls sound like long-distance international calls. So the users have to be aware of the "you-talk-then-i-talk" phenomenon. As for the asymmetrical path, that should really not be a problem, you should just ensure that your routing protocol is aware that the VSAT path consists on two simplex links connected to 2 different ports. I am assuming here that your VSAT uses a DVB-IP receiver for downlink traffic and an SCPC modem for uplink traffic. George Murage - jvd wrote: jvd, it's nice to have you on the list. It looks like you post using the Web site. A lot of people do GroupStudy via e-mail. They can't tell what your messages refer to. They seem like orphans. When posting from the Web, please press the Quote button first and then add comments, and your messages will arrive with some context. Thanks. > > Hello Pieter, > > As you know delay is one of the problems with VSAT. You can do > nothing about hops to the satellite and back. What you need is > some prioritization/QoS in your network for the voice traffic. > There are various ways to do this. But is prioritization and QoS even worthy bothering with for traffic going to a satellite? Wouldn't that be sort of like priorizing which bus leaves the New York bus station first to avoid delay going to San Francisco? The few minutes saved by letting the San Fran bus leave before the Philadelphia bus are completely irrelvant compared the many days it takes to get to San Fran. On routers, the few nanoseconds saved by outputting voice first are irrelvant compared to the hundreds of milliseconds to reach the satellite. > > I don't have personal experience with AutoQoS but it's a new > feature supported on the Cisco routers and switches - check it > out: (you may need a CCO login) > http://www.cisco.com/en/US/partner/tech/tk543/tk759/tk879/tech_protoco > l_home.html > > My other suggestion is for if you want to get into the details > to configure your equipment manually, is to have a look at the > QDM (QoS Device Manager). This is a web based tool that is free > from Cisco's website. > http://www.cisco.com/en/US/partner/products/sw/netmgtsw/ps2063/index.h > tml > > And then my final suggestion is to have a look at RSVP > (Resource Reservation Protocol). This protocol will reserve > bandwith for your application along the transmission path. > > Regards, > Jans > > PS. Nice to see fellow SAfricans on the forum. I thought you were from Brazil?! Now I am curious! :-) Priscilla Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71775&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Multimedia/Voice over VSAT [7:71706]
Janó van Deventer wrote: > > > > On routers, the few nanoseconds saved by outputting voice > first > > are irrelvant compared to the hundreds of milliseconds to > reach > > the satellite. > > > Yes maybe, but won't you run into trouble with jitter? A small variation in delay (jitter) when the delay is huge anyway might not matter? > And then also I think that if you don't have some kind of > prioritization/fragmentation to take care of big data packets > you can also have a problem with smaller sized voice packets. > I'm thinking here in the line of FRF.12 (fragmentation for > voice on frame-relay networks). I don't know what's a similar > technique for satellite networks... Back to my bus station analogy. You're now talking about letting the San Francisco bus go ahead of the train to Philadelphia to save a few minutes, when it takes days to get to San Francisco anyway. It's a good question really. Is it worth it to do link fragementation and special queuing to improve voice and video on a satellite link? I think he said the relevant direction is a 1 Mbps link. Anyone want to comment on this? Please. PPP has fragmentation and interleaving, so he could use that on the satellite link. > > > > > > > > PS. Nice to see fellow SAfricans on the forum. > > > > I thought you were from Brazil?! Now I am curious! :-) > > > I'm posting from sunny Brazil, that's right! I met a Brazlian > girl in SA and made the big decision to move to Brazil, learn a > new language, and the rest is history. Sounds exotic! One great thing about this list is the ability to communicate with people all over the world. It's great to have you here. Regards, Priscilla > > Kind regards, > Janó Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71785&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Multimedia/Voice over VSAT [7:71706]
Hi All, Well, we all know that due to technology advancements, today the IPLCs (or read leased line circuits) are a lot cheaper so there is not real need to transport voice or video on Satellite links, but then the satellite links do have much more uptime guaranties, so enterprises do consider satellite for backup options. Now I have seen many implementations of voice on satellite media, and if you can do away with the basic apprehensions about time delay, voice quality is just fine on satellite too. I mean you can manually inject a satellite kind of delay (550+ msecs) on any end-to-end fiber implementations and the voice quality will be more or less same. So if we are really running voice on satellite medium, we should do all possible things to ensure that the voice has its own share of bandwidth so that it does not suffer due to the non-availability of bandwidth. HTH Vikram -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 02, 2003 10:54 PM To: [EMAIL PROTECTED] Subject: RE: Multimedia/Voice over VSAT [7:71706] Jans van Deventer wrote: > > > > On routers, the few nanoseconds saved by outputting voice > first > > are irrelvant compared to the hundreds of milliseconds to > reach > > the satellite. > > > Yes maybe, but won't you run into trouble with jitter? A small variation in delay (jitter) when the delay is huge anyway might not matter? > And then also I think that if you don't have some kind of > prioritization/fragmentation to take care of big data packets > you can also have a problem with smaller sized voice packets. > I'm thinking here in the line of FRF.12 (fragmentation for > voice on frame-relay networks). I don't know what's a similar > technique for satellite networks... Back to my bus station analogy. You're now talking about letting the San Francisco bus go ahead of the train to Philadelphia to save a few minutes, when it takes days to get to San Francisco anyway. It's a good question really. Is it worth it to do link fragementation and special queuing to improve voice and video on a satellite link? I think he said the relevant direction is a 1 Mbps link. Anyone want to comment on this? Please. PPP has fragmentation and interleaving, so he could use that on the satellite link. > > > > > > > > PS. Nice to see fellow SAfricans on the forum. > > > > I thought you were from Brazil?! Now I am curious! :-) > > > I'm posting from sunny Brazil, that's right! I met a Brazlian > girl in SA and made the big decision to move to Brazil, learn a > new language, and the rest is history. Sounds exotic! One great thing about this list is the ability to communicate with people all over the world. It's great to have you here. Regards, Priscilla > > Kind regards, > Jans Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71823&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Multimedia/Voice over VSAT [7:71706]
Priscilla Oppenheimer wrote: > > Janó van Deventer wrote: > > > > > > > On routers, the few nanoseconds saved by outputting voice > > first > > > are irrelvant compared to the hundreds of milliseconds to > > reach > > > the satellite. > > > > > Yes maybe, but won't you run into trouble with jitter? > > A small variation in delay (jitter) when the delay is huge > anyway might not matter? > > > And then also I think that if you don't have some kind of > > prioritization/fragmentation to take care of big data packets > > you can also have a problem with smaller sized voice packets. > > I'm thinking here in the line of FRF.12 (fragmentation for > > voice on frame-relay networks). I don't know what's a similar > > technique for satellite networks... > > Back to my bus station analogy. You're now talking about > letting the San Francisco bus go ahead of the train to > Philadelphia to save a few minutes, when it takes days to get > to San Francisco anyway. > > It's a good question really. Is it worth it to do link > fragementation and special queuing to improve voice and video > on a satellite link? I think he said the relevant direction is > a 1 Mbps link. Anyone want to comment on this? Please. Priscilla, Since you asked so nicely... Not that I'm aware of. Shamefully, VoIP is one of those technologies I haven't even tried to stay current with. In general, any protocol that involves acknowledgements will need to be monitored closely and possibly tweaked when SATCOM is in the mix (just as is the case with any other type of LFN). I guess it's a pretty safe assumption that VoIP uses UDP. So I doubt acks are an issue. And I agree with your assessment that the delay associated with fragment size is very small relative to SATCOM delay. I suppose one could take the approach that any little bit helps. But the human ear isn't likely to discriminate the very small advantage, if any advantage at all is realized. Having said that, if large segments/fragments/whatever were introducing substantial jitter, thereby degrading voice quality, fragmentation might be of some help (but that would hold true in any situation - it wouldn't be unique to SATCOM applications). I don't know how much buffering is involved where the typical VoIP solution is involved. I suspect it would have to be a tradeoff, as too much jitter-smoothing buffering would cause noticable delay in delivery. Just a few rambling thoughts from someone who knows SATCOM quite well, legacy voice to fairly well, and next to nothing about VoIP (yet)... Scott > > PPP has fragmentation and interleaving, so he could use that on > the satellite link. > > > > > > > > > > > > PS. Nice to see fellow SAfricans on the forum. > > > > > > I thought you were from Brazil?! Now I am curious! :-) > > > > > I'm posting from sunny Brazil, that's right! I met a Brazlian > > girl in SA and made the big decision to move to Brazil, learn > a > > new language, and the rest is history. > > Sounds exotic! One great thing about this list is the ability > to communicate with people all over the world. It's great to > have you here. > > Regards, > > Priscilla > > > > > Kind regards, > > Janó > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71851&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Multimedia/Voice over VSAT [7:71706]
""Vikram JeetSingh"" wrote in message news:[EMAIL PROTECTED] > Hi All, > > Well, we all know that due to technology advancements, today the IPLCs (or > read leased line circuits) are a lot cheaper so there is not real need to > transport voice or video on Satellite links, but then the satellite links do > have much more uptime guaranties, so enterprises do consider satellite for > backup options. Now I have seen many implementations of voice on satellite > media, and if you can do away with the basic apprehensions about time delay, > voice quality is just fine on satellite too. I mean you can manually inject > a satellite kind of delay (550+ msecs) on any end-to-end fiber > implementations and the voice quality will be more or less same. So if we > are really running voice on satellite medium, we should do all possible > things to ensure that the voice has its own share of bandwidth so that it > does not suffer due to the non-availability of bandwidth. a long time ago when it was believed that satellite would be the ultimate WAN technology, there was a radio station in San Francisco that would occassionally put their highly rated morning talk show host in New York or Washinton to do live shows with various people of importance. The delay was so annoying that they decided to go back to land lines. For a long time afterwards, ISDN and switched 56 were the means for coast to coast conversations. In fact, I believe that this paritcular station has set up most of its current talk host lineup with ISDN in their homes as the means for remote broadcasting. lesson - satellite may be wonderful, but beware of delay. > > HTH > > Vikram > > > -Original Message- > From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED] > Sent: Wednesday, July 02, 2003 10:54 PM > To: [EMAIL PROTECTED] > Subject: RE: Multimedia/Voice over VSAT [7:71706] > > Jans van Deventer wrote: > > > > > > > On routers, the few nanoseconds saved by outputting voice > > first > > > are irrelvant compared to the hundreds of milliseconds to > > reach > > > the satellite. > > > > > Yes maybe, but won't you run into trouble with jitter? > > A small variation in delay (jitter) when the delay is huge anyway might not > matter? > > > And then also I think that if you don't have some kind of > > prioritization/fragmentation to take care of big data packets > > you can also have a problem with smaller sized voice packets. > > I'm thinking here in the line of FRF.12 (fragmentation for > > voice on frame-relay networks). I don't know what's a similar > > technique for satellite networks... > > Back to my bus station analogy. You're now talking about letting the San > Francisco bus go ahead of the train to Philadelphia to save a few minutes, > when it takes days to get to San Francisco anyway. > > It's a good question really. Is it worth it to do link fragementation and > special queuing to improve voice and video on a satellite link? I think he > said the relevant direction is a 1 Mbps link. Anyone want to comment on > this? Please. > > PPP has fragmentation and interleaving, so he could use that on the > satellite link. > > > > > > > > > > > > PS. Nice to see fellow SAfricans on the forum. > > > > > > I thought you were from Brazil?! Now I am curious! :-) > > > > > I'm posting from sunny Brazil, that's right! I met a Brazlian > > girl in SA and made the big decision to move to Brazil, learn a > > new language, and the rest is history. > > Sounds exotic! One great thing about this list is the ability to communicate > with people all over the world. It's great to have you here. > > Regards, > > Priscilla > > > > > Kind regards, > > Jans Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71863&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Multimedia/Voice over VSAT [7:71706]
Hi All, Well, we all know that due to technology advancements, today the IPLCs (or read leased line circuits) are a lot cheaper so there is not real need to transport voice or video on Satellite links, but then the satellite links do have much more uptime guaranties, so enterprises do consider satellite for backup options. Now I have seen many implementations of voice on satellite media, and if you can do away with the basic apprehensions about time delay, voice quality is just fine on satellite too. I mean you can manually inject a satellite kind of delay (550+ msecs) on any end-to-end fiber implementations and the voice quality will be more or less same. So if we are really running voice on satellite medium, we should do all possible things to ensure that the voice has its own share of bandwidth so that it does not suffer due to the non-availability of bandwidth. HTH Vikram -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 02, 2003 10:54 PM To: [EMAIL PROTECTED] Subject: RE: Multimedia/Voice over VSAT [7:71706] Jans van Deventer wrote: > > > > On routers, the few nanoseconds saved by outputting voice > first > > are irrelvant compared to the hundreds of milliseconds to > reach > > the satellite. > > > Yes maybe, but won't you run into trouble with jitter? A small variation in delay (jitter) when the delay is huge anyway might not matter? > And then also I think that if you don't have some kind of > prioritization/fragmentation to take care of big data packets > you can also have a problem with smaller sized voice packets. > I'm thinking here in the line of FRF.12 (fragmentation for > voice on frame-relay networks). I don't know what's a similar > technique for satellite networks... Back to my bus station analogy. You're now talking about letting the San Francisco bus go ahead of the train to Philadelphia to save a few minutes, when it takes days to get to San Francisco anyway. It's a good question really. Is it worth it to do link fragementation and special queuing to improve voice and video on a satellite link? I think he said the relevant direction is a 1 Mbps link. Anyone want to comment on this? Please. PPP has fragmentation and interleaving, so he could use that on the satellite link. > > > > > > > > PS. Nice to see fellow SAfricans on the forum. > > > > I thought you were from Brazil?! Now I am curious! :-) > > > I'm posting from sunny Brazil, that's right! I met a Brazlian > girl in SA and made the big decision to move to Brazil, learn a > new language, and the rest is history. Sounds exotic! One great thing about this list is the ability to communicate with people all over the world. It's great to have you here. Regards, Priscilla > > Kind regards, > Jans Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71895&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: RE: Multimedia/Voice over VSAT [7:71706]
interactive voice over satellite is problematic due to the inherent latency of the signal travelling 40,000km distance to the satellite and another 40,000km back. this adds 125ms of latency in each direction (to/from the bird), give or take. if you remeber using satellite for long distance calls it took some getting used to (a bit like talking on a 2 way radio) and the perceived signal quality was less than using an under the pond cable. satellite for 1 way video is fine, carriers use it for backhaul on a regular basis, but interactive video suffers the same difficulties as interactive voice. so with the amount of latency already involved i would try to reduce any further quality impairments caused by voip or digital video processing. satellite offers a variety of quality impairments of its Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71943&t=71706 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
