Here’s the info/flyer on the workshop I’m taking & contact info for arranging this for your area.

University of Wisconsin-Madison
Department of Engineering Professional Development

Understanding and Troubleshooting Videoconferencing Networks

ITU H.323 is the primary standard for videoconferencing over IP or other packet networks.

In this course, you will go through the standard function by function and view examples, studies and applications. You will also discuss typical problems and issues and be able to visualize them with the help of a sophisticated protocol analyzer. Key topics include:

• Standard components, including terminal, gatekeeper, gateway, and multipoint controller
• How voice, video and data flow over H.323 and how calls are processed in the network
• Problems with video and voice over packet networks and how they are addressed in the standards
• How ITU H.323 relates to the IETF Session Initiation Protocol (SIP), MGCP and Megaco
• Options for handling firewalls in an H.323 network
• What is the new H.264 codec? How does it relate to the H.261, 262 and 263 codecs?
• What is available in troubleshooting and analysis tools and techniques?
• New developments in H.323, including directory services, security and calling features

Who Should Attend

• Network engineers, managers, and operators who need to understand how to provide voice, video and data services in a public or private network
• Individuals who design, manufacture, sell and service network equipment
• Advanced users of multimedia conferencing services in education, advertising and business services
• IT support staff and ISP support staff who work with customers of H.323 based networks

For More Information
We can deliver this course to your site, tailored to your needs. To discuss delivery options, please contact:

Thomas W. Smith, Program Director
Engineering Professional Development
432 North Lake Street
Madison, Wisconsin 53706
Phone: 800-462-0876 or 608-263-7426
Email: smithtw@engr.wisc.edu

Today & tomorrow I'm attending a workshop on "Understanding and Troubleshooting Videoconferencing Networks". I was worried it would be over my head because it's really geared to networking people, but I am learning! The workshop is coordinated by ETOM and attendees are from K12, community colleges, and colleges around Michigan. The workshop is from the University of Wisconsin, and they could come to your state too! Tomorrow I'll post more details on how you could arrange for this in your area.

Here are some of my "take aways" from today's session.

H.323 was designed for corporate LANs
Now I know why sometimes I feel like I'm pushing the edges of this technology – with events like MysteryQuest and Read Across America and really any classroom-to-classroom projects. Because all use of IP videoconference outside of your own network is really beyond what the original designers of the H.323 standard envisioned. Among other things, they did not think of firewalls at all when designing the protocol! Which explains why we're having such troubles connecting to each other outside our networks! While this knowledge doesn't solve anything, it explains the root of the problems that annoy me daily. It also explains some of my frustration with vendors. The vendors are working within the H.323 standard and also mainly considering the corporate world. The design issues that affect the projects I want to do are there because the vendors never thought of using it quite the way we do with K12 projects. Having this perspective tempers my annoyance.

H.323 is for voice too
You probably knew this already, but I just learned it today. The H.323 protocol is used in Voice Over IP. SIP is the competing standard. Interesting to know.

Different versions of H.323
The H.323 standard is evolving and growing. So there are different versions of H.323. This explains several things. Why you can have two H.323 units that have issues connecting. Why you can have an "H.323 aware firewall" and it doesn't work with the endpoint. It also reminds me of the importance of paying for maintenance on endpoints. That way you get the upgrades as they fix issues and implement the new version of H.323. In theory things work better with the latest version.

H.325 is coming down the pike
Another standard is in discussion that addresses several issues with H.323. It is probably a few years in the future at least. Hopefully it will be backwards compatible. Either way, don't get too settled in the status quo! Change is always coming… especially with technology!

Interoperability Events
The IMTC runs interoperability events where vendors get together and test their equipment to see how they connect to each other. I'm glad to know that they do this considering how much we connect to "unknown" units around the world!

Gatekeeper/Gateway
In my first two years of dabbling with IP, we had a Radvision Gateway/Gatekeeper. I'm not even sure now exactly what model it was. It did the functions of both the gatekeeper and gateway. I didn't understand the difference and used the terms interchangably. Well, now I've learned that the gateway converts between H.323 and H.320, and the gatekeeper controls and directs calls. Sometimes they are in the same box, some times the gatekeeper is packaged with a router, sometimes the gatekeeper and/or gateway are incorporated into the MCU. It helps to understand the functionality so that I can use the correct terms!

Endpoints Signaling Firewalls
The industry is very aware of the firewall issues. Much of the current work is now being done on the endpoint signalling the firewall. This sounds very promising and is encouraging to know! Another reason to pay maintenance contracts to get the new software upgrades as they address these issues.

Gatekeepers and Endpoints
The basic H323 call model is from network (IP) address to network address. However all other higher level call models use a gatekeeper (dialing plans, etc.). These call models "increase functionality." I put that in quotes because these gatekeeper call models assume a corporate network world. They don't address the unique issues that seem to arise mainly in the K12 world where we just want an IP address to call the other endpoint so our classes can do projects together. Calls that require gatekeepers, gatekeeper registration, and neighbor gatekeeper registration all increase the complexity of the calling. Although in theory they are intended to make it easier to call other people.

Right now my videoconferencing is primarily all in the direct IP address to IP address dialing world. But from what I learned in the workshop, vendors, standards, etc. are all moving in the direction of gatekeeper controlled dialing. So what does that mean for K12 videoconferencing? I'm still mulling it over.

There is a project called Videnet mainly in higher ed communities to use the Global Dialing Scheme. Some schools have experienced this dialing scheme when participating in Megaconference or Megaconference Jr. Many K12 schools in the United Kindgom are just now switching to IP and they are incorporating GDS. You can review this clear explanation of this scheme and how it is being implemented in the UK. These cooperative dialing schemes require higher level coordination and obviously the purchase of gatekeepers to make it all work. Is this where K12 VC in the U.S. should be heading? If so, how do we get there? Some states have statewide networks that would make this kind of dialing scheme easier to implement. In other places, a district or a building can buy an endpoint, hook it up, and be on their way doing videoconferencing, without a thought of the big picture or even without any knowledge or awareness of a wider dialing scheme. How would we address that? I'm thinking out loud here. What do YOU think?

I'm sure I'll learn more tomorrow and will write again….

Here’s an interesting blog entry from Wesley Fryer, an educator in Texas, on XMeeting, open source software for connecting to H.323 sites and conferences from the Mac. He has included screen shots so we can see how the program works. Looks promising!

Yesterday I spent quite a bit of time helping one of our school district troubleshoot an IP call. Here are some of the things we tried.

Check the IP Address
One of the first things to check is the IP address that the other location gave you to dial. In this case, the first number they gave us was a 10.10.xxx.xxx number. Any number that starts with a 10 or 172 is an internal IP address and so you know up front that you can't dial that number if you are not on their network. When this happens, ask the other location to give you an "external IP address" to dial.

How have other connections worked?
The next investigation is how can both sides connect? Ask yourself and the other location – where else can I connect that it works? Can I connect with other places outside my network? Has it been tested recently with another location? In sorting through this conversation, we discovered that both locations could only place IP calls. Neither could receive. So then we set up a connection on my bridge so the two places could call in and meet each other there.

Partial Connections
Next we discovered that we were getting video & audio from the other location, but they couldn't see or hear us. They were seeing a black screen. This is a red flag for firewall problems. It's VERY common (at least in my experience) to have the connection work almost all the way, but one or two parts are missing. Often the firewall lets the call connect, but doesn't allow the incoming audio & video. At this point you ask the other site to check the ports on their firewall or ask them if they've successfully connected to someone else outside their network.

On this particular call, we gave up on IP and went to ISDN. That was as much of a challenge as they gave us three numbers for a switched call. We ended up making it work with a 2×64 call and I bridged it from myPolycom VSX 7000. Thankfully the connection went well.

May 21, 2007 Update:  See the latest comments on my bridge here.

Please note this was originally written in May 2006 and versions have changed since then. See the comments section for TANDBERG’s response. – Note added March 2007.

First Things First
First before I write about some comparisons, let me describe my base assumptions and biases.

1. My use of videoconferencing is almost totally connecting with
“unmanaged” units, or places outside of my service area. These are
other schools that connect in a myriad of ways, and who don’t
particularly want to be registered to my gatekeeper, because I connect
to them only once or twice a year. Some connect through bridges
(Radvision, Polycom MGCs, old Accords, etc.), some connect directly,
some connect via IP, and some connect via ISDN. Read Across America, MysteryQuest, and other such projects and events are what we do with videoconferencing. Hence
I connect with a ton of unknown units all the time. And I expect that
to work consistently (with a test call ahead of time of course!).

2. As an educational service agency supporting videoconferencing, I
expect my MCU to be able to connect to anything. My goal with my MCU is
to provide services and connections to my districts that they could not
do on their own: multipoint events, IP/ISDN conversion, connections
they can’t make on their own.

And some background. I have 35 (soon to be 70) Polycom endpoints and a Tandberg
MPS (vJ3.0), gateway, gatekeeper and Tandberg Management Suite (TMS). The comparison is with my colleague Arnie Comer‘s
bridge: an Polycom MGC 100 and he supports 140 Tandberg endpoints. We both use our bridges as described above.

This comparison is not on all the features that either bridge can
do, but on the features necessary to support K12 videoconferencing as
described above.

Comparison

So I have come to the conclusion that the Polycom MCU is the
workhorse of videoconferencing, connecting all types of units together.
The Tandberg bridge seems to be heading towards a closed network model
with great wonderful fancy features for closed networks. But it does
not handle IP address dialing well at all and the company
doesn’t seem to be designing their systems to support IP address dialing.

Disclosure Statement: Polycom is sponsoring the BCISD Videoconference Program Database. They also link to my blog. However, they do not dictate, edit, or preapprove anything I write here.

A few weeks ago I followed with interest a Megaconference listserv discussion about LifeSize and it’s support of video protocols. Here is a comment by John S. Martin, from the JANET Videoconferencing Management Centre, University of Edinburgh.

When multipointing in a multi-user environment we have found several incompatibility issues which are only resolved when one, or all, of the connected codecs connected at H.261. This is the base standard for H.323 videoconferencing. Yes, a video protocol transcoded conference will overcome this issue, but this uses more resource on an MCU such as a Polycom MGC. I
have spoken to lifesize about this and apparently it was a commercial decision not to implement H.261, but something they may look at in the future, depending on demand.

I just find it bizarre that a company have developed a system which doesn’t connect to H.261/3/4 video protocols.

Usually I’m not thinking much about video protocols, but I was very interested in this conversation. The Megaconference listserv has many international higher ed technicians and I learn a lot just by reading the messages. It was intriguing because some people thought it didn’t matter. Why would a high definition VC product want to connect to a low end legacy product that could only do H.261?

This conversation concerned me, coming from a K12 VC environment where usually there is much less tech support. Some districts have a teacher who is responsible for the videoconferencing equipment, and that’s it! That teacher or media specialist expects the connection to work if it’s IP or ISDN and they usually don’t know anything about the video protocols. It’s enough to remember H.323 or H.320! As K12 endusers, we just want it to work! You want to be able to talk to someone, find out if they have videoconferencing, and have it work!

So I have a few thoughts and reflections based on this experience.

Learn From Others! If you participate in Megaconference or Megaconference Jr., stay on the listserv after the event is over! Even if the conversation seems like it’s way over your head! That’s how I felt when I first participated in Megaconference a few years ago. But I’ve stayed on the listserv and “lurked” and learned a lot about the technical back end details of videoconferencing that I wouldn’t have learned otherwise. Another good place to learn about technical details is the VTC Talk Forums.

Talking To Your Vendor. If you’re new to videoconferencing and are talking to your vendor, there are some things you should consider. Some of this advice is based on experiences with connecting to other schools for MysteryQuest, Read Across America, and similar projects. 9 times out of 10 your vendor will not have imagined these types of uses of videoconferencing and so may try to convince you otherwise.

1. You definitely need to be able to dial out to an IP address. And if possible, you need a way to get to ISDN sites as well. Not all of the providers have switched to IP yet. And some schools that you might want to connect to are also ISDN. Sometimes your educational service agency (ISD, BOCES, ESC, etc.) can provide this service for you. Or your vendor may have ideas of how you can get access to ISDN if needed. ISDN usage in K12 videoconferencing has diminished greatly in the last year or so, but if you truly want to be able to connect to anyone, you’ll need a way to convert to ISDN occasionally.

2. Second, you really need to be able to receive calls, preferably to an external IP address. There are a few content providers who prefer to call the school they are connecting to. There are also many great projects you can do with other schools. But if you partner up with a school that can only call out, and you can only call out, then you are stuck! This is a big problem in the Read Across America project and spin off projects that use the same format. There are new firewall traversal units coming out to help schools with the challenges of IP videoconferencing. However, sometimes these tools create an environment where you have to dial an extension to get to the right unit. Some schools connect through a bridge, and the bridge can’t dial an extension. All these things complicate projects that should be able to happen easily! So if at all possible, design your system so that you can receive calls to an external IP address. Otherwise, you may need your educational service agency to help you make connections with other schools.

3. Have as little as possible in between your VC unit and the rest of the world. In my experience with IP calls, the more “boxes” (firewalls, gateways, bridges, & stuff) are between two units, the lower the quality of the call. If you are in a consortium, design your system so you can make calls with or without the assistance of a central bridge. It’s good to be independent of that bridge if at all possible. I’m finding that my calls work better and have clearer pictures when connected directly. Some of the newer units can do beautiful H.264 calls that look great! But not all the bridges and gateways and stuff in between allow that protocol through.

H.323 has made videoconferencing cheaper and more accessible to schools, but it has also added a level of complexity to connections that is sometimes hard to navigate. But that’s the nature of the beast these days it seems.

Just ran across this interesting blog entry, Polycom Rocks…. A learning technologies conference in Australia gave away PVX software and a free webcam to the participants! What a great idea! Wish I had attended! I also heard recently that the state of California negotiated a statewide license for PVX software for education.

I’m very curious how these entities will be using their PVX software. It’s interesting how this top notch quality product blurs the lines between “room” videoconferencing and desktop videoconferencing with tiny web screens and tools like Skype & Festoon. With PVX and a little Logitech webcam you can get a full screen high quality H.323 videoconference that looks amazingly good!
While I have reservations about schools jumping into VC with PVX instead of a regular VC unit, I’ve recommended this to one of my tiny private schools that wouldn’t be able to do videoconferencing otherwise. It’s a bit of a stretch to use PVX with a room full of kids, but with a small class size of 15 or so, it’s almost manageable. The challenge is the microphone is designed for use by one person at a computer, so students have to come up closer to the computer to connect. Not ideal for projects like Read Across America and MysteryQuest, but doable.

On the other hand, the PVX solution is GREAT for meetings, quick conversations with colleagues, and for monitoring conferences from my office! Now in theory I can watch three conferences at a time with a VSX7000, a Viewstation, and PVX on my laptop.

I wonder what is next in the convergence of videoconference technologies!

Spent the day today with TWICE colleagues Arnie Comer, Sue Porter, and Connie Solis sitting in a conference room at the MACUL conference in Grand Rapids waiting for the network details to be setup for our videoconferences tomorrow. AVI Systems graciously loaned TWICE a Polycom VSX 7000 and peripherals to do videoconference sessions all day tomorrow and Friday.

We had a funny experience. Due to a scheduling glitch we couldn’t set up in the room we will be in tomorrow, so we set up temporarily in another room to do test calls this afternon. No screen though. And the wall was pin striped. Very hard to read the diagnostic settings, etc. projected on a pin stripe wall! So, resourceful Mike from ICI set up a makeshift screen: the switch we were connecting through. Not a very big screen, but it did the trick. I wish we had been able to take a picture so I could share it here!

Everytime you take equipment to a hotel or conference center to do videoconferences it’s an adventure! Today was no exception!

Now that it works, we are looking forward to a great line up of sessions for the TWICE room at the MACUL conference!