Anyone using DSL lines

[whitebuffalo]

I have a few endpoints that are currently connected via ISDN-BRI at isolated locations. They arent used enough to really justify a T1 line and the local network people wont let them on. Has anyone used DSL for a connection? I can put in a DSL for cheaper than the current ISDN-BRI monthly charges. i was thinking put in a DSL, a simple firewall (linksys?), then the codec. then, register the codec to my network through my border controller to give them ISDN access etc.

will this work? anyone tried it? potential pitfalls?

[Niel.C]

DSL = public internet
public internet = no QoS
no QoS = low/uncertain video quality

That being said, I'm sure some folks out there are doing exactly that and making it work.
Why won't your network people let your endpoints on?? I bet if you offered to cut your ISDN lines and pay them half of what you were paying for the ISDN lines, they would at least consider it. You still have to pay, be it for ISDN or IP bandwidth, the questions is which will give you the best video quality at the most appropriate cost.

At least to me it is. :knockedou

[Sean Lessman]

I have a few endpoints that are currently connected via ISDN-BRI at isolated locations. They arent used enough to really justify a T1 line and the local network people wont let them on. Has anyone used DSL for a connection? I can put in a DSL for cheaper than the current ISDN-BRI monthly charges. i was thinking put in a DSL, a simple firewall (linksys?), then the codec. then, register the codec to my network through my border controller to give them ISDN access etc.

will this work? anyone tried it? potential pitfalls?

Should work fine if you have a good provider. I have Verizon FIOS and it is outstanding. I rarely if ever get packet losses even when using my PC to download at the same time. I think I pay $49 a month for 15Mbps down and 2Mbps up -- works great.

Sean

[whitebuffalo]

i run a seperate network just with vtc b/c the network guys wouldnt let me play. the orders were from the top......

fwiw, i've had pretty good luck across the internet using my t-1, we do it pretty regularly. just wasnt sure of the DSL solution.

Thanks for the tips, i will keep y'all posted.

[mockenga]

I've done H.323 video conferencing over DSL several ways and they both worked passably well, with some drawbacks.

I was the video engineer for a managed IP service provider with a QoS-enabled core, and we were an approved ISP for the local phone company's DSL service. Running our QoS-based IP over non-QoS enabled DSL/ATM worked pretty well in tests, since the DSL carrier's network was overbuilt and didn't introduce much additional latency or jitter. Ultimately, it wasn't a market gain for us, so we never productized it.

I've also done plenty of "internet"-bound calls that exited our QoS network via our internet links and connected to DSL-based sites. They were not as consistently high quality and were more prone to audio and video loss, but worked well enough for normal use. If video/audio quality is super critical, you will want to avoid it though.

As a network engineer who forayed deep into video engineering for several years, I'm consistently surprised by conflict between the two houses. I found them very compatible.

[Sean Lessman]

I've also done plenty of "internet"-bound calls that exited our QoS network via our internet links and connected to DSL-based sites.

TANDBERG used AT&T public internet circuits in full production for well over 3 years before moving to MPLS. For the most part, worked very well and I would suggest the incremental benefit of the MPLS network isn't worth the additional cost. Just my experience.

If you stay consistent with the same provider to all of your offices minimizing peering points where ISPs put little to no effort, you should be fine.

That being said, like I said above, I use FIOS at home and it is rock solid. Probably as good at our AT&T circuits were a few years back.

Until we moved to MPLS, TANDBERG never used QoS and rarely missed it...but then again, we had plenty of bandwidth so we really didn't need it.

Sean

[JFCOMEngineer]

I have a few endpoints that are currently connected via ISDN-BRI at isolated locations. They arent used enough to really justify a T1 line and the local network people wont let them on. Has anyone used DSL for a connection? I can put in a DSL for cheaper than the current ISDN-BRI monthly charges. i was thinking put in a DSL, a simple firewall (linksys?), then the codec. then, register the codec to my network through my border controller to give them ISDN access etc.

will this work? anyone tried it? potential pitfalls?

Yep, did it, and it works, with caveats.

There are several different flavors of DSL, and not all of them work well. Recently a customer (small manufacturer located in rural Virginia) ordered a new DSL circuit for their new VTC system. The circuit that was delivered was A/DSL, 128K up, 384K down. This was corrected by changing them to a different carrier that was able to give them higher bandwidth, but it serves to illustrate what has been the most signifigant problem I have encountered with DSL. Most of the systems I have installed have been at SO/HO locations, and they want to share the residential DSL circuir between several computers and the VC equipment. If the compny is picking up the tab for the connection it's seldom an issue, but if the company says that they will allow someone to telecommute, but it's for the employee's convience then the employee is out of luck and will have to pay for the upgrade themselves. The folks with cable modems or AT&T FiOS seem to do OK, but the regular DSL over copper suscribers have problems.

If you can get DSL with adequate bandwidth, and can live with the problems inherant with using the public internet, then it's the way to go.

Regards,

Wes

[warheed]

Should work fine if you have a good provider. I have Verizon FIOS and it is outstanding. I rarely if ever get packet losses even when using my PC to download at the same time. I think I pay $49 a month for 15Mbps down and 2Mbps up -- works great.

Sean

Hi Sean,

Will it really work with let say, 521Kbps upload and 4 Mbps download? We have tried to connect on one site that has this connection and we could not see any video and could not hear any audio on our side, when i checked the packet loss, it is as high as 65 percent (our receive). we tried connecting to another site that uses a 384kbps upload and download and the result was perfect. Why is that they said it is not recommended to use a connection with a different upload/download? I always hear those things but honestly I dont know the reason.

Thanks a lot.

[Sean Lessman]

Why is that they said it is not recommended to use a connection with a different upload/download? I always hear those things but honestly I dont know the reason.

The issue is the codec expects to have the same bandwidth in both directions (symmetrical) when you dial a certain speed. If you want to send a different speed on the upload side than you are receiving use the following API command:

h323rate txvideo <16..1920>

Change the txvideo speed to something lower than your network upload speed.

Lastly, if you have to pass through a bunch of peering points or are a network sharing bandwidth with a bunch of high school kids downloading stolen music etc, you are probably going to get packet loss. The idea is to use the same provider as much as possible and your experience should be ok.

I have had terrible luck with cable companies and packet loss, so I wouldn't recommend it. The Verizon FIOS service I have is outstanding and is rock solid.

Sean

[whitebuffalo]

the MXP 1000 will be the only thing on the DSL, should i put a firewall in front of it (something simple) or would it be ok to be out in the open?

[Sean Lessman]

the MXP 1000 will be the only thing on the DSL, should i put a firewall in front of it (something simple) or would it be ok to be out in the open?

We do not require a firewall for our products to work, however it is strongly recommended. Only you can make the decision on the security of your deployment, I cannot recommend that you do without a firewall.

Sean

[YeOldeTechy]

I have a few endpoints that are currently connected via ISDN-BRI at isolated locations. They arent used enough to really justify a T1 line and the local network people wont let them on. Has anyone used DSL for a connection? I can put in a DSL for cheaper than the current ISDN-BRI monthly charges. i was thinking put in a DSL, a simple firewall (linksys?), then the codec. then, register the codec to my network through my border controller to give them ISDN access etc.

will this work? anyone tried it? potential pitfalls?

I've used DSL at home for years. I like to throttle down to 256 kbps (just because I know I'm pushing the upstream a bit) but it also works at 384 kbps. I use Polycom PVX, ooVoo, and have tested Mirial Softphone and Sightspeed on a laptop. I have used old Viewstations at home as well....but primarily now computer-based.

I have had no problems...works great. I use Windows firewall...

[whitebuffalo]

got it set up initially. the only synchronous dsl they had was 384. i was getting avg speeds of 320 each way. :( so i had em bump up the service to 6 MB down 768 up for 5 bucks more per month. i set the transmit video speed like sean mentioned. i will test this afternoon.

[whitebuffalo]

this unit has been up and running for over two months now and i'm happy to report is working quite well. i throttled it to 512 and the user has reported zero problems and is happy with the performance. thanks to all for the input.

[jmaslak]

We've been running on DSL in Wyoming State Government for years, with some major caveats.

1. Not all DSL works well. Be prepared to upgrade.

2. It works best when you are your own ISP

3. You better hope the telco's DSLAMs are not over-subscribed

4. You probably should run enterprise-grade routers (like Cisco 1801s), not low-cost DSL routers.

5. We always get the highest speed DSL we qualify for, and never run anything but video over the line. The office network connection will be a seperate circuit.

We also do some occasional internet DSL in areas we cannot be our own ISP - it works okay, mostly, but has all the problems of internet video conferencing. We do this in areas where T1-class serverice costs upwards of $1,500/month - we simply don't have that type of money for sites that seat very small numbers of participants. The thing we've learned here is that most ISPs will provide routers that have no provision for setting duplex/speed on the ethernet side, not all understand what "we need a static IP" means, not all providers are created equal, and always get the fastest connection you can - 384K video conferencing works much better over a 4mb/s down/768 up internet DSL line than it works over a 512k x 512k line - it shouldn't matter, but it does.

We're pretty lucky in the areas we're able to be our own ISP, as these lines almost always run as clean as leased lines and we see pretty much no packet loss, jitter, etc.

[orish]

DSL = public internet
public internet = no QoS
no QoS = low/uncertain video quality


This is ridicolous ISDN-addicted talking. DSL, PPPoE and PPPoE with fixed public IP is working fine if you have enough upload.

Its a myth that without QoS you cant do videoconferencing. Take a SDSL or ADSL with twice of the bandwith you want to use for your videocall and fire it up.

We are doing HD 1 MBit/s call across Europe, to Asia and the US. All that talking about "if you dont have QoS you cant to it" is preventing people and companies from doing videoconferencing over IP. But its reality and really good working since a long time! Fact!

[JFCOMEngineer]

DSL = public internet
public internet = no QoS
no QoS = low/uncertain video quality

That being said, I'm sure some folks out there are doing exactly that and making it work.
Why won't your network people let your endpoints on?? I bet if you offered to cut your ISDN lines and pay them half of what you were paying for the ISDN lines, they would at least consider it. You still have to pay, be it for ISDN or IP bandwidth, the questions is which will give you the best video quality at the most appropriate cost.

At least to me it is. :knockedou

This is ridicolous ISDN-addicted talking. DSL, PPPoE and PPPoE with fixed public IP is working fine if you have enough upload.

Its a myth that without QoS you cant do videoconferencing. Take a SDSL or ADSL with twice of the bandwith you want to use for your videocall and fire it up.

We are doing HD 1 MBit/s call across Europe, to Asia and the US. All that talking about "if you dont have QoS you cant to it" is preventing people and companies from doing videoconferencing over IP. But its reality and really good working since a long time! Fact!


First point: It's really rude to take an out of context snippet from a post and use it to imply a message that reading the entire post doesn't support. Sorry, that's just a pet peeve, had to get it off my chest.

Second, and to answer Orish's response to Niel.C's post to the original topic, as always, the real answer is "It depends." There is a real issue if you have to use the public internet for your communications path. It's not correct to say that Point-to-Point Protocol over Ethernet (PPPoE) makes VTC work fine over the public internet. That simply isn't what PPPoE does. For a more complete explanation the wikipedia article on PPPoE (http://en.wikipedia.org/wiki/Point-to-Point_Protocol_over_Ethernet) does a pretty good job without getting too technical.

There are tunneling protocols that will help with some of the problems associated with the public internet, but I have yet to find a solution that allows access over the public internet at the same quality as my internal networks with QoS enabled. Notice I carefully did NOT sat that it couldn't be done, just that I have never had it where I could see it.

All of the preceding aside, you can (and we do) conduct unclassified videoconferencing on the public internet. Yes, there is latency, and dropped packets that affect video quality, occasionally significantly.
For most purposes the quality is adequate, but remember, Cisco doesn't achieve the high quality on their TelePresence system by using superior endpoint equipment and processing, they do it by requiring that you use their carefully managed, dedicated network with QoS that has been optimized for RTP video and audio traffic.

Regards,

Wes