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ASK THE EXPERT – IP VIDEO CONFERENCING

Welcome to the Cisco Networking Professionals Ask the Expert conversation. This is an opportunity to discuss IP Video Conferencing with Cisco expert Alan Glowacki. Feel free to post any questions relating to this topic.

Alan may not be able to answer each question due to the volume expected during this event. Our moderators will post many of the unanswered questions in other discussion forums shortly after the event. This event lasts through April 26. Visit this forum often to view responses to your questions and the questions of other community members.

30 REPLIES
New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Hi, Alan

My question - Can be H.323-ID's compatible with Microsoft Active Directory users or other directory services ?

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

H.323-ID's can can be just about any alphanumeric identifier that a user or administrator chooses. Are you looking for directory services for your endpoints? If so depending on the endpoint ILS, LDAP and Proprietary systems such as Polycom's GMS can be used.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

I have number of 2611s connecting to a 3640 via 64k sat phone isdn lines. Via this means I'm expected to provide streaming video, I know its always going to be of poor quality but can anyone give me any suggestions on how to make this as efficient as possible. Any suggestions would be greaty appreciated.

bblancha@bigpond.net.au

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

streaming video using RTP/UDP based video probably wouldn't work over this link and there's not much you can do about it. Some streaming solutions such as Real or Microsoft WMT allows you to stream using TCP. Viewers at the far end will buffer the video until a sufficient amount of data is available for display. If there are a number of users on the far end, you may want to consider Cisco's CDM/CE solution. This will allow you to proactively cache content on the far side (using an FTP puch to local content engines), then viewers can watch streaming media from a local source eliminating the challenges your WAN creates.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Trying to determine appropriate Cisco solution for client with five branch locations and a central location. Client wishes to use VPN technology with T1 internet connection at each location. Client Requirements are Tight Security via a Firewall, Voice Over IP, Video Conferencing, Email, Collaboration Suite, Intranet. I have viewed the entire line of Cisco offerings for VPN and each of the required applications separately, but it seems Cisco would have a solution that incoroporates the ability to do all of this in one hardware bundle. Any help would be greatly appreciated.

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

I would suggest getting copies of the Design guides for Voice, Video Conferencing and QoS. The QoS design guide will give you recommendations for deploying QoS for all of your applications in a number of environments, while the other guides will give you details for each application. Cisco goes to great lengths to provide design guides for different technologies. Covering every scenario in every environment would be very difficult. If you need help locating the design guides send me an email or contact your SE.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Hi Alan

we have a video confrenceing setup based on ip using ip bridge when we connect more that 3 locations at one time the video and voice starts freezing as well as some time it becomes still, if i reboot the equipment then it starts working.

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

What is the bridge(MCU) and if it is a Cisco box what is the code revision you are running? Are these sites coming across a WAN link or all connected on the LAN? I would also suggest hardcoding the switch port the MCU is connected to at 100M full duplex. We have seen issues with auto negotiation of half and full duplex.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

We do some ip video over our network using Polycomm equipment. Our infrastructure is all Cisco switches and routers. Wan Sites tie back to us over T-1's.

We have an issue with audio drops at one site. This particular site goes through a 3524 switch to a 2620 router which ties to a T-1 which connects to a 3640 at another site and back to us on a T-1 into a 3660. We have upgraded all of the IOS versions and implement QOS using policy maps on all three routers and dedicating 768 kbps.

A show policy map interface command indicates that packets are being matched during conference calls and TAC indicates it is setup correctly. The site still experiences audio drops (up to 10 and hour) on the remote end.

We have changed out the polycomm equipment and also changed out the 3524 and 2620 on their end.

We have other sites that traverse two T-1's with 2620's being the middle man and in one case Cisco 424 hub to a 2509 as the starting point tied to another T-1 and 2509 and back to us on a T-1 with no issues regarding quality of either video or audio. And these devices have no policy map or QOS setup.

Any suggestions?

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Some questions first:

1. What version of code are you running on your routers?

2. What is the data rate you are running your video calls at?

3. Are these calls point-to-point or multipoint?

4. You mention audio drops I would assume you are seeing video problems as well?

5. Have you tried a point-to-point call from the system/site having issues to another video system on the same network (without accessing the WAN)?

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

1. The 2620 at the problem site is running 12.2.1, the middle 3640 router is running 12.2.7 as is the 3640 at the head end.

2.The calls are generally 384k but have been attempted at 256k with no better results.

3.Calls are multipoint most of the time but the problem occurs on point to point calls also.

4. I havent actually been in these conferences, but apparently there is a little lightning bolt that appears in the corner when the audio drops occur. It has always been reported to me specifically as audio. Weve had this problem over a year.

5. No. We have not tried that. But we have replaced the polycomm unit as well as the networking hardware at that site (CSU, V.35, 2620, 3524). We have also replaced the internal csu at the middle site as well as the CSU, V.35 cable, moved the connection to another interface on the router on our end as well as upgrade to the 12.x series for the qos features.

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

I would suggest hardcoding the Ethernet port that the Polycom is connected to 10 meg half dulplex. The system may be having duplex negotiation issues. Have you looked at the switch the system is connected to? I would first try and eliminate any local issues by trying a call between two units at that site (even if the second unit is netMeeting) to rule out any issue with the system or LAN. It sounds like you have gone through the configurations with TAC. What type of queuing are you using?

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

You might want to look at the buffers on your routers. I had similar problems and changing the various buffers, (Cisco told me the proper changes) helped a great deal. It appeared that the small and middle buffers get nailed by Videoconferencing. All those small updates on the screen I guess.

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Couple of things I would suggest checkin on both the 2620 and 3640.

1. Make sure videoconferencing traffic is being serviced from a Priority Queue. If that is not available use CBWFQ and use modular QoS to assign a bandwidth value to your videoconferencing traffic.

2. Provision at least 420k per 384k call that will traverse the link.

3. Verify that access to the video queue is secure. if you have only a single endpoint at each site create an access list with the enpoints IP address and use that to map the video traffic into the correct queue.

Here is an example with the Priority queue in a LLQ. if you don't have this option you can change the statement "priority 450 30000" to bandwidth 450 30000"

class-map Video-Conf

match access-group 102

!

policy-map QoS-Policy

class Video-Conf

priority 450 30000

class class-default

fair-queue

!

Video-Conf Traffic

access-list 102 permit ip host 10.5.10.100 any precedence flash-override

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

What PolyCom equipment are you using. I had a similar experience with video jitter. Try upgrding the software in the PolyCom.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Hi Alan, I'm using an MCU Cisco IPVC 3540, I registered it on a Cisco gatekeeper on a 2611 router. I want to use the VCWizard scheduler of Magicsoft. I know that the scheduler can communicate with the GK with SNMP messages, I want to understand what is necessary to enable on the Cisco Gk to obtain a communication with that scheduling program and what is necessary to do if I want the Mcu Dial-out the end-points automatically.Thanks.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

We are currently in the process of converting 3 of our remote offices from 512K Frame Relay connections to full T1 Internet circuits, from Qwest.

At HQ we have 2 T1s running MLPPP for a combined 3mb of bandwidth.

At each of the 3 remote offices have an Cisco MC3810 (each with 32mb RAM/8mb Flash-running IOS 12.1(9)), Cisco Pix 501 Firewall (running 6.1(3)), and a Polycom Viewstation 128 (running v7.2 software).

At HQ we are using a Cisco 3662, Cisco Pix 515 (Unrestricted- running v6.1(3)-with 4 Interfaces [2 are currently being used]), Cisco IP/VC 3510 MCU (running v2.2.1.0.9), and a Polycom Viewstation 128 (running 7.2). The Pix firewalls are configured for a full-meshed IPSEC DES VPN.

The problem that we are experiencing is that the Polycom Viewstations will register with our IP/VC 3510 MCU, but when we go to place a call utilizing the 3510, it doesn't go thru. I have tried to telnet into the 3510 to see if it is seeing the requests for a session coming from the end-piont, and it does NOT. Although I am able to see the Registration Requests come thru.

Currently the MC3510 is sitting on the Inside Interface of my PIX515, but we would like for our clients to be able to connect to the 3510 to participate in conferences involing several of our outside offices. With this in mind, I believe that the 3510 needs to get moved to our DMZ interface on the Pix515.

Or will a static command on the PIX work?

Any help is greatly appericated.

Kenneth L. Higdon

Qk4, Inc.

www.qk4.com

khigdon@qk4.com

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Our school is currently looking into a distance learning solution we can setup in a classroom and allow students to view the class from their home computer. We would like to send audio and video to them and receive questions back, possibly with a message manager or something similar. I have investigated IPTV and would like to ask you how you think the quality and feasibility of IPTV as a solution. Thanks for any input you can give me.

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

The feasability of IPTV in your particular environment depends on a couple factors. First of all you mention that students would be viewing the class from their home computer which for IPTV is problematic because the most common access would be through the internet which doesn't support Multicast which is the only way that IPTV streams out live events. In this senario, IPTV is best suited in environments where QoS can be administered (again something that is not available over the Internet) and Multicast is supported. Secondly, one way to address video quality is by determining how much Bandwidth can be appropriated to the actual stream. Again back to the Home user, bandwidth is limited in most cases so the stream that they would recieve is of low quality. More Bandwidth = beter quality so if the home user has broadband they will have beter quality than if they only have dial-up. In my experience you have to provision for the lowest common denominator which is dial-up so these streams won't be as useful. If you have a plan that addresses bandwidth to the home you can increase the quality but still have QoS and Lack of Multicast support over the internet working against you. In most solutions such as you describe, IPTV is not as useful as Real or Windows Media. If you can control the network, such as in a LAN environment , IPTV delivers higher quality and more features which make it a preferred solution for an internal learning solution.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Thanks for the input.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Alan,

I am looking for some guidance on design rules for H.323 video on Frame based IP networks. I have read the Cisco Cisco "Designing Internetworks for Multimedia" document and understand most aspect but have difficulty in estimating bandwidth requirements.

I am looking to design a Frame Relay based IP network capable of supporting 30 fps video.

Based on research of various vendor solution (polycom, Sony, Pictutel etc) there seems to be a variation of range from 56k-320k for 15 fps and 384k-768k for 30 fps. Existing H.320 ISDN based systems generally utilise 128k or 384k for these frame rates.

Are there any basis rules of thumb that can be used, especially for bandwidth estimation.

RegardsBernie Gowdie

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Bernie,

There is a videoconferencing design guide available that covers all of these issues.

The link is posted in the video forum at:

http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.ee725eb/174

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

That's simple:

If the terminals support RSVP, the bandwith function: BW*(100-25)%=VBW . With better quality(30F/S NTSC), you had better use the VBW over 512Kb/s.

But if your system running over FR,you should have more buffer for BW, Because the CIR of FR looked not very useful when the FR switch meet colision

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

Alan,

What documents would you recomend to review, if we were concidering IP/VC, that would show us the best diagrams, configuration, QoS and what Type of Lines needed, etc. We have several WAN connections that we would like to utilize.

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

You want the videoconferencing desing guide, it has everything you are looking for:

javascript:newWin('http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.ee725eb/174')

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

T.120 Polycom and Cisco MCU's

We are Cisco ATM “end-to-end” and are having problems with our 3510 MCU/Gateway and the PolyCom units with the latest software. I have updated our MCU/Gateway with Cisco’s latest update and am still having problems with T.120.

We got a listing last night from Polycom on what MCU’s they work with and Cisco was not even mentioned....which is weird...perhaps they were only listing the “newly” supported MCU’s with their upgraded software??

Feb 20, 2002, 6:59am PST

Have just purchased a 3510.

I cant seem to get the data sharing working.

I am doing my tests with MS Netmeeting 3.01 on W98SE, the conference I am connecting to has T.120 enabled.

I get three clients to join the conference, goto the conference web page,

select a user and click Data Share, if Im on the same PC as netmeeting I get

a message saying “The person you called is not registered with the

gatekeeper”

Cary Orlando, Fl.

Video/audio works fine in the conference. Point to point conferencing allows data sharing to work.

Any ideas?

Paul

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

This is a known issue with NetMeeting. When you register NetMeeting with the gatekeeper and place a video call everything is fine, as soon as you go to start a data sharing session the NetMeeting client sends a request to the Gatekeeper using an E.164 of the called endpoints IP address. The call fails because the gatekeeper doesn't find the IP address in the list of active E.164 adresses. The only work around that I am aware of is to take another NetMeeting client that is not registered with the gatekeeper (and not in the video call) and initiate a T.120 session. I know that this was reported as a bug I will check and see what the status is. As for us not being on the Polycom tested list, our 3510 is OEMed from Radvision and will fall under that platform for tested products.

New Member

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

We are considering deploying a Cisco CDN. I have seen some reference that the Cisco CDN can also be used to do video conferencing. Can you provide some insight into this.

Cisco Employee

Re: ASK THE EXPERT – IP VIDEO CONFERENCING

I am not a CDN expert, but my short answer would be no. People have also tried to use IP/TV for videoconferencing and found that it wasn't the right choice. Products meant for one way streaming video tends to be built for network delay and this is done with very large buffers on the end stations. Some have delays of up to 3 seconds which makes intactive communication very difficult. Stick with videoconferencing technologies for interactive video, they are built for very little delay and will give you the quality your users will expect.

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