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Video Killed the Radio Star

April 14, 2008 | Chris Payatagool
nwlogo-06.gifBy jimandneil_simplified

Its a no-brainer that IP-based video applications are increasing at a dramatic rate, and its having a dramatic affect on network traffic. A recent study/white paper by Cisco attempts to quantify the growth and provide a glimpse into the future. According to this paper, video traffic on the internet in 2007 exceeded the level of traffic on the entire internet in 2000.


"The Exabyte Era"

cisco.com...net_implementation..pdf


Anyone Can be a Film Studio

But what is driving all the video traffic? It is a combination of factors culminating into the "perfect storm". What do you need for an application or technology to go mainstream? You need several factors including a low barrier to entry, something that simplifies the technology, add a dash of the killer application, and voila, you have a technology that goes mainstream and grows exponentially. For video, think about 5-10 years ago when video cameras became so affordable and prevelant that just about everyone bought one and became and amateur video producer. Barrier to entry number one removed. But still, it wasn't that easy to be a distributor and distribution networks were not common.

But today, social networking sites like YouTube, MySpace and many others appearing every day have dramatically lowered the barrier to video publishing to the point where anyone can do it. So video cameras are so common that almost every cell phone, PDA, laptop, digital still cameras, and oh yeah...video cameras themselves, provide a pretty high quality video capture. If so inclined, video editing software is also cheap and easy to use. Add to that a free, global video publishing and distribution system, and essentially anyone, anywhere can be a film producer. Our kids showed us a couple films they shot and edited and we were amazed. With little or no training, they are making movie shorts that rival those at Cannes (hey, they are our kids, yes we are biased).

What Does it Mean for Corporate Networks

If you administer a corporate network, you may be saying at this point "so what, that's a consumer phenomenon, it does not apply to me." We say, think again. The cross-over is already happening. First, you have alot more applications relying on video that are finding their way onto converged IP networks. Traditional video conferencing over IP networks was just a toe in the water. Add to that Telepresence, IP video surveillance systems, broadcast communications, training VoDs, desktop video conferencing, digital signage, and so on, and the video "spectrum" of the network starts to get a little crowded.

Second, if you have not seen it already, social networking is coming to a corporate net near you. Ask yourself, why have social networking trends zeroed in on video as the predominant communication medium? Easy. Video is the most effective medium. People can show or demonstrate concepts much more effectively and easily using video than any other.

Just as the progression occurred from voice exchange to text, to graphical, to powerpoint slides, video will start to supplant those forms of communications. Think about the time it would take to create a good set of slides describing how to setup one of your company's products. Now how much easier would it be just to film someone doing it? That's one of many examples that is happening. Soon enough, all sorts of intellectual property will shift from documents and slides to video clips.

The point is, if you think the video phenomenon is just for consumers, you may want to check your wallet for the Flat Earth Society card and discard it soon.

PART 2


In the first segment, we talked about several major trends that are increasing the amount of video traffic on corporate networks. In this second segment, we look at what you can do to start to get a handle on the impacts to your network.

Understanding Video Application Behavior

First, and foremost, the term "video" gets tossed around alot as an application, but in reality its a technology that enables or is included in many applications. Each video application has its own unique model of behavior and requirements on the network. So you need to understand the applications using video and understand their behavior. Some critical questions to ask include:

   1. Where are the video sources and where are the viewers?

   2. Which direction do the video flows traverse the network?

   3. Is the video stored and viewed or real-time interactive?

   4. How much bandwidth does the application require, static and burst?

   5. What are the service level tolerances (latency, jitter, loss)?

   6. What are the likely usage patterns in your company?

   7. Are there requirements to connect to other companies (or customers)?

   8. In what direction is the application likely to go in the future?


Lets look at a couple examples. First, lets look at Desktop Video Conferencing, which for our purposes here will mean using either a computer with a camera or a fixed videophone to conference with other people having similar endpoints. Our analysis might look something like:

   1. Video sources: desktops, Viewers: desktops

   2. Direction: desktop to desktop, or desktop to conferencing server

   3. Real-time interactive

   4. Bandwidth: 2 x 768kbps per call, bursting up to 1Mbps

   5. Tolerances: latency<250ms jitter<20ms loss<0.5%

   6. Usage patterns: adhoc meetings between any employee at HQ or branch offices

   7. Other companies: not at this time

   8. Future: likely shift to High-Def within 5 years


So that we can illustrate the importance of understanding the differences, lets look at one more example of IPTV, which will mean broadcasting of a stored or live video stream to many simultaneous viewers. Our analysis might look someting like:

   1. Video sources: video storage servers or live feed, Viewers: desktops

   2. Direction: storage to desktop, or live feed to desktop

   3. Stored and viewed (but possibly also real-time for live feed)

   4. Bandwidth: 1 x 512kbps per stream, bursting up to 512kbps

   5. Tolerances: latency<250ms jitter<20ms loss<0.5%

   6. Usage patterns: simultaneous viewing by many employees at HQ or branch offices

   7. Other companies: not at this time

   8. Future: integration with other apps


By this simple analysis we can understand quite alot. One of the important differences is where is the video orginating and where are the consumers. For destkop conferencing, obviously the sources and consumers are both the desktop. So the impacts to the network are very likely to be within the HQ Campus switching network, across the WAN, and to Branch Office networks. Provisioning may be a bit hard to predict as the likely usage will be fairly ad-hoc conferences. Voice calling patterns may lend insight into likely video calling patterns.

To contrast, the sources of IPTV streams are typically in the Data Center, from high-speed video storage servers. Because viewers can be essentially any employee, this will affect the HQ Campus switching network, WAN, Branch Offices, and possibly even remote workers over VPN. Since there will be many simultaneous viewers, it is inefficient to duplicate the video stream to each viewer, so wherever possible we would like to take advantage of broadcast optimization technologies like IP multicast and stream splitting.

Getting Your Arms Around the Apps

In this simplistic example, you can see why its important to understand how different video applications behave in order to understand how they are likely to impact your network.

Start by making a table with (at least) these questions in mind and inventory the applications using video today and in the future. Common requirements will emerge, such as the need to meet "tight" service levels, the need to optimize bandwidth, and the need to optimize broadcasts.

There is also a couple critical decisions you need to make regarding your video-enabled network strategy. Are you going to comprehensively manage video applications, or just a few that are critical to your business? What is going to be your policy and treatment of "un-managed" video applications, such as the hordes of streaming video content sites on the Internet?

PART 3


In this last segment, we will look at some specific things you can do in your network to prepare it to be "Video Ready".

Video Apps on Your Network

First, the poll results (keep in mind multiple voting was allowed, so many of you have several different types). Let's group the results so we can talk about them later in the article.

    Group A: about 1 in 5 are using Streaming Internet Video, Desktop Video Conferencing, and Room-to-Room Conferencing

    Group B: about 1 in 10 are using IP Video Surveillance, Web 2.0 Intranet Embedded Video Clips, and Video-on-Demand (VoD)

    Group C: about 1 in 20 are using Digital Signage, Re-broadcasting feeds, Webcams, Personal video clips, and Telepresence

These results are pretty much along the lines we see with prevailing video trends in the networking industry. "Group A" above are the most established video applications, a mixture of streaming video and real-time interactive video. "Group B" represent the "next wave" of streaming video applications as new convergence opportunities are attractive (e.g. IP Video Surveillance) and as Web 2.0 transforms the internet. "Group C" are video applications that are still in early adoption, but quickly growing, again a mixture of streaming (Signage, Personal) and real-time interactive (Telepresence) video.

What is Your Video Strategy?


In the last segment, we also posed a question to ask yourself as a network administrator or network architect: what will be your strategy for video? We see different approaches from the companies we work with. Some embrace video entirely, seeing it as driving the next wave of productivity for their business. Others adopt a stance to manage and protect select video applications on the network. Still others are in a bit of denial, and would rather pretend video isn't there yet. What should you do?

If we have learned anything from past productivity enabling technology "waves", it is this: if IT doesn't deploy it, users will....and usually poorly. Think about Wireless LAN several years ago. Some IT departments were skeptical of the need, or questioned (rightly so) security, so deployments lagged. Users responded by purchasing their own consumer-grade WLAN AP's and plugging them into your network. Ouch.... Nothing can put a damper on your network security strategy like a bunch of "rogue" AP's in your network, without proper WLAN security...and often without the ability for you to locate them to shut them off.

We believe the video app wave will be no different. Its already happening. If you don't embrace an IT-led deployment of video clip production and distribution (think MySpace replaces your employee directory), an ad-hoc server is liable to show up under someone's desk. If you don't embrace an IT-led deployment of desktop video conferencing (think personal High-Def video), people will buy their own consumer-grade webcams and try to do it.

We also believe networks are at a crossroads: they will either evolve to be a "Video Ready Network" or network administrators may find themselves in the Wild West, with 50, 60 or 70% of their network traffic being un-managed video apps. Our point is: pick a strategy whether its fully embrace, partially embrace, or strictly control. Having no strategy is not much of an option.

What Can You Do to Make Your Network "Video Ready"?

After you understand the behavior of the different video applications in your network (or that may be on your network someday soon), draw common threads of requirements between them. Here are a few common ones:

1. High Availability


Data apps are tolerant of multi-second interruptions, VoIP and Video apps are not. If you have already been beefing up your network with VoIP convergence in mind, excellent, you are a step ahead. If not, then it's really really time. For VoIP and especially real-time interactive video apps, the user experience matters and to achieve it, the network needs to deliver very low latency (100-150ms end to end), very low jitter (0-10ms) and increasingly, low loss.

Loss requires a bit more explanation and may warrant a dedicated article to do it justice. But to make it simple, HDTV video formats take billions of bytes to transmit and they are not practical without compression codecs like MPEG4 or H.264. If you compress the equivalent of several thousand packets into one packet, and you lose that packet, you effectively lose thousands of packets. For data apps we were sometimes happy with 1-2% loss. For VoIP we tightened our expectations to say 0.5-1%. For video (especially High-Def) think order of magnitude reduction, 0-0.05% loss.

In short, build your network with built-in low-latency, sub-second failure convergence, and as close to zero loss as possible.

2. Quality of Service (QoS)


Again, QoS is not new as hopefully you have applied it to your network to protect your existing critical applications. If you already have QoS in place for VoIP, fantastic, you need to extend it to include Video apps. If you have not, then now might be a really good time to consider doing so. You may say "But my apps have worked fine, why do I need QoS now?"

The answer is that video consumes bandwidth...lots of bandwidth, far more than VoIP. If you added VoIP to your network without QoS, and it worked, you may have gotten lucky that a bandwidth hungry app didn't chew up the bandwidth you needed for high quality VoIP calls. Why not just throw more bandwidth at the problem?

Bandwidth alone doesn't solve the problem. Think of it like a freeway. Onramps control flow of new traffic, there are slow lanes and faster lanes, and overall speed limits. All these controls work together to move the most amount of traffic safely through the highway. Without those controls, you are likely to have a free-for-all with major pile-ups that more lanes is unlikely to solve.

Identify which applications you want to protect in your business, whether they are data, VoIP, and/or Video, and implement a comprehensive QoS service policy to mark and prioritize traffic.

3. Bandwidth and Latency


As we said, video apps need bandwidth, and also relatively low latency packet delivery. In a campus switching network, make sure you have enough bandwidth at the aggregation points and through the core (such as 10GigE).

Don't forget about your branch offices. Many, many people in the typical large company now work in satellite or branch offices away from the main headquarters. These folks will expect no less than the same set of video-enabled apps as your HQ employees. In fact, they may rely on them even MORE because of the need to communicate effectively with corporate.

Survey your WAN speeds and make decisions now about which branch offices need to be upgraded to higher speed and/or secondary WAN connections. Some quick calculations based on the number of seats in a branch office can give you a quick indicator about bandwidth needs. For example, suppose there are 20 people in a branch office and your company relies on desktop video conferencing for collaboration, streaming video for training and corporate communcations broadcasts, and plans to install IP video surveillance cameras at all branches for security. Lets further assume a 5:1 over-subscription on conferencing.

    desktop video = 4 simultaneous calls to HQ x 512kbps

    training VoDs = 2 simultaneous x 384kbps

    video surveillance = 2 x 512kbps

    VoIP = 5 simultaneous calls to HQ x 128kbps

    data apps = 64kbps x 20

With simple estimates, we can pretty easily see that we may need 6Mbps or more for our WAN speed, and our current T1 is not going to cut it.

One thing we can do is to "harvest" bandwidth, using WAN optimization technologies such as Cisco Wide Area Application Services (WAAS), which using compression and optimization can give us back 20-50% or more of our current WAN bandwidth, without sacrificing application speed. WAAS or any other WAN Optimization technology is unlikely to save bandwidth of Video apps themselves, because of the high degree of compression already "built-in" to most video codecs. The point of implementing WAN Optimization is to "clear" bandwidth from other apps to be re-used by newer or expanding apps.

Many people ask: should I optimize my WAN or upgrade the bandwidth. The answer is: both. Optimizing the WAN will allow the most conservative upgrade path.

4. Broadcast Optimization


Several popular video apps, including streaming video, video-on-demand (VoD) training, corporate broadcast communications (e.g. IPTV) and others have a behavior model of a single or few video sources and many simultaneous viewers. Whenever you have such video apps, you want to optimize these broadcasts so that preferrably you send a single (or few) packet streams on the network that viewers can join, instead of each viewer requiring their own dedicated packet stream.

IP Multicast is a good technology that can be leveraged to optimize such video apps. If you already have IPmc enabled in your network, great, you are a step ahead of the game. If not, it may be time to consider turning it up.

Stream "splitting" is another alternative starting to appear in products aimed at the WAN and branch office networks. Effectively stream "splitting" behaves alot like IP multicast, only instead of a real multicast packet stream in the network, usually a proxy device receives the stream at the branch office over the WAN and then handles "join" requests, much like a rendevouz point in IPmc. Cisco's WAAS product is one such product that has an integrated "stream splitting" capability for certain types of video streams.

5. Visibility

It is more important than ever to understand the applications running on your network, what resources they are consuming, and how they are performing. Whether you are trying to insure a high-quality experience for video conferencing users or trying to understand how YouTube watchers may be impacting your network, its important to have visibility into the network.

Tools like Cisco NetFlow and tools like it can be essential to understanding what portion of traffic flows on your network are your critical data apps, your VoIP apps, your "managed" video apps, and the "un-managed" video (and other) apps. For example, if you discover that YouTube watchers are consuming 50% of the WAN bandwidth to your branch offices, potentially squeezing out other business critical apps, it may be time to put some usage policies into place or even more drastic measures such as network-based policing.

Another important aspect is to understand how the business managed video apps are performing? What kind of experience are users receiving? One way to proactively monitor such apps are using network-based tools such as IP Service Level Assurance (IP SLA), which can be programmed to send periodic probes through the network to measure critical performance parameters such as latency, jitter, and loss. It can be helpful to discover troublespots with long-latency times, for example, and take actions with the Service Provider (or other root cause) to correct them before users get a bad experience and complain.

Summary

Video applications are increasing exponentionally on the IP network. It is best to adopt a proactive strategy to understand how these apps will affect your network now and into the future. By taking an inventory of video-enabled apps and understanding the new and changing requirements they will place on the network, it is possible to successfully manage through this next evolution of IP convergence, and take steps to enable your network to continue to be the converged platform for your company's communications and collaborations.

[via Network World]










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