An Enterprise Video Communications Industry Lite Paper Demystifying CDNs: Building Video Enabled Networks That Maintain Your Network Integrity And Meet User Demand
Overview In recent years video has taken a huge step up in use on the Internet and for enterprise communications. Video is now used for Company Town Hall meetings, live or on demand webcasts, product and sales training, financial broadcasts, IPTV, digital signage, customer outreach, videoconference recording and streaming, and even in place of audio calls. As the use of video proliferates, so can the resulting network traffic. It s important to review and analyze how this new technology can be delivered efficiently over corporate networks to minimize the impact on your IT infrastructure and ensure high video quality. A Content Delivery Network (CDN) is the natural fix for the issues that evolve around using video as an effective tool in any organization that desires to take advantage of any of the benefits of video communications. In this Lite Paper, both Live and Video on Demand broadcasts are the predominant video use case in corporate communications, and will be discussed. A short questionnaire that can be used to evaluate your needs for a CDN in your enterprise is available at the conclusion. For the highest consistent video delivery quality, and lowest impact on an organization s network, it is important to get the content cached as close to the end user as possible. CDNs become vitally important in the scope of a successful video delivery project. What is a CDN? A Content Delivery Network (CDN) is a group of networked computers, or edges, that cooperate transparently to deliver content to end users. These edges provide an increase in video performance, scalability and cost efficiency.
How are CDNs Delivered? CDNs can be bundled as software, servers or appliances but they all do the same task they store and forward content for the end user to access. A CDN is normally described as the backend software that is used to deliver the content to the different edges. This doesn t include the portal used to view the video or host the taxonomy for easy access. This is handled by other software that can utilize the CDN though an API or command set. CDNs can be used over an enterprise network or over the Internet. CDNs can vary in size from just a few locations, to hundreds or thousands of locations depending on the quality, volume and scalability requirement of the content being delivered. Three of the most popular Internet based CDN solutions (icdns) include Akamai, Limelight and AT&T ICDS, which can host consumer focused content/services such as customer videos or web content. They are also used for enterprises to publish videos to the internet for marketing or other purposes. Enterprise CDN solutions (ecdns) include: Qumu MediaNet, Blue Coat Director, Cisco ACNS, and Riverbed RSP which integrate with the network to improve video delivery for internal users, in a highly secure and network efficient manner. Both types of CDNs meet the needs of customers depending on whether end users are accessing the site from the Internet or internal within the Enterprise network. The Role of CDNs in the Enterprise A CDN s primary role in the video hierarchy is to cache the content and provide reduced buffering and speedy delivery of video similar to what is expected with television. In an enterprise environment, caching and fast video delivery is handled by either supporting multicast for live video, or by placing edge servers near end users, where Video on Demand (VOD) videos are delivered via fewer hops. This results in lower latency and increased delivery speed, and minimizes bandwidth used for transporting video streams. Another important role for the CDN is in repeating the video signal by stream splitting at the edge for live content.
CDN Delivery The three most popular ways to deliver live video to the enterprise are: WAN Multicast, LAN Multicast and LAN Unicast. WAN Multicast Live video distribution can be set up for the entire enterprise from as little as one server, as long as each WAN uplink and each LAN is enabled for Multicast, and the proper Quality of Service is replicated throughout the entire enterprise network. WAN Multicast normally costs a certain amount each month on each network link. This can be very high for international locations and remote locations with low bandwidth. LAN Multicast This Multicast option can be an easy way to minimize use of LAN network bandwidth. Similar to WAN Multicast, only one stream is running on the LAN, thereby not affecting the network as heavily. For WAN networks that are not multicast enabled, placing an edge that can turn a Unicast stream into a Multicast stream uses the same bandwidth on the LAN as a WAN Multicast stream and doesn t involve the extra effort of enabling multicast on all the WAN links. LAN Unicast LAN Unicast means that you will have edges at each location similar to LAN Multicast, but the distribution is limited to the bandwidth available on the LAN. With enterprise network speeds reaching 1Gb, LAN Unicast is a much more viable option then it was a few years ago, and is normally the choice for companies that have no capital to spend on upgrading the entire network to support Multicast. It is the lowest performing of the three choices, but is normally the lowest cost as well. An important reminder when considering LAN Multicast or LAN Unicast is that the upstream bandwidth from the central location goes up for each edge added in the system. For that reason, it s important to correctly evaluate the extent of the network before deciding on a live video topology. Most enterprises use a combination of all three solutions, enabling them to reach the most customers for the least cost. But only certain CDNs allow the flexibility to finetune your network to handle these options.
CDNs Who Should Use Them? Managing the content on a CDN has become an issue for large deployments and is one of the primary deciding factors when choosing a CDN. A leading candidate for a CDN is an enterprise that has employees spread out from the central office who would benefit from having their content available with a low level of latency locally versus from a centrally managed server. There are very few companies that would not benefit from a CDN when it comes to Video. The performance increase when serving video content locally versus over the WAN can be extreme. With a properly set up CDN, video will not affect the other aspects of network traffic, saving companies money on expensive network upgrades and ensuring adequate performance for all applications on the network. One other reason a company should choose a CDN is if they are going to be doing both Live and Video on Demand (VOD) broadcasts. Where Live can be supported with a WAN multicast setup described above, that doesn t apply to VOD. With VOD, it is always important to get the content as close to the consumer as possible, while providing the appropriate streaming protocol for the type of content provided. It s important to have a way to easily and efficiently publish content to multiple CDNs yet, only a few solutions are available for this. Also, when companies have different CDNs for different purposes or locations, the most important aspect is to have a video content management and publishing system that can manage these myriad CDNs while directing users to the correct location and edge. Enterprise CDN Selection Unfortunately, some current CDNs on the market don t support the required video protocols, and may treat video as if it comes from a web server instead of an enabled streaming server. The two most popular video formats used are Flash and Windows Media and it is important to know if your CDN supports one or both. For a CDN to support Adobe Flash or Windows Media, the CDN requires licensed technology to properly stream both live and VOD content. In recent years there has been a surge of companies that support some protocols while treating other types of content as HTTP web content. While this will work, you will never get the performance that you would from a true streaming protocol.
For example, most Cisco ACNS customers think that they should be able to add Windows Media streaming without any problem, but in reality they have to buy new licenses for each of their CEs. For some customers the cost of this could be in the millions of dollars. One solution for this is to turn on one or two CEs for Windows Media and then webcast live video across the enterprise WAN using Multicast. In this scenario, Video on Demand will still be treated as if it was a web server for the enterprise, which limits the performance and scalability of the solution. This option is being used by many enterprises in exactly this setup. However, this approach is not ideal. Serving a video as HTTP instead of RTSP with Windows Streaming technology is about the same as playing baseball without a glove. You can do it, but no one is going to enjoy it. 1 Additionally, before choosing a CDN, it is important to determine if your video use/delivery is going to be VOD or Live or both and whether your current video management application can support CDNs or can it be adapted to work with them? Many companies that produce live and VOD webcasts have not fully planned or strategized how to manage their video. As a result, a number of companies create a template that is set up for each video and then placed out on a web server or streaming server. While this is a solution that can work, it is not considered an enterprise solution and will not properly utilize the CDN for its capabilities since CDNs are built to handle hundreds or thousands of videos. These environments are prone to user frustration and complaints about poor video performance. Additional areas you may also want to include in your CDN evaluation: Certain CDNs can be set up to work as a cache, which means they will, in theory, work with any management system, while others require integration with the API to be able to push content to the edges. The API will allow pre positioning of content to the edges as well as starting and stopping live streams, which makes any Live or VOD broadcast much more efficient. Will your enterprise be required to work with multiple CDNs? This is common when there is both internet (icdn) and enterprise (ecdn) traffic requirements, organizations that have purchased or acquired multiple ecdn products, or if there are different types of content being broadcast. To create and distribute videos in both Flash and Windows Media, a company may need both a Wowza or Adobe Flash Media Server and Microsoft Windows Media Server running on the network. 1 For further information, see: http://www.d.umn.edu/itss/support/training/online/streamingserver/weborstream.html. Web delivery (http) from a Web server or podcasting server does not take advantage of streaming. Many people think they are streaming when they are just making a file available for download, but this is okay as long as they know what can happen with their file.
Summary As the use of video proliferates, it s important to review and analyze how this new technology will be delivered. A Content Delivery Network (CDN) is the natural fix for the issues that evolve around using video as an effective tool in the enterprise, but CDNs and video content need to be managed. Before choosing a CDN, it s critically important to determine whether you will be supporting Live Video or Video on Demand, or both, at what times and in what volumes and whether you have a content management system that supports CDNs. Ultimately, it s important to not only leverage the power of CDNs but also the power of a centrally controlled video management and distribution application such as the Qumu Video Control Center for your Live and Video on Demand webcasts. By 2013, more than 25% of the content that workers see in a day will be dominated by pictures, video or audio. Globalized workforces will benefit from nontextual documents in video formats because they depend less on spoken or written language, and because such supplementary elements may be more easily replaced. Enterprise information managers should act now to discover how video is permeating business operations, where it faces customers and whether it is considered to be a document of record. Source: Video Killed the Document Czar by Whit Andrews, Gartner, November 7, 2008 Video plays an increasingly strategic role in the way enterprises communicate internally and externally. Video has the power to draw audiences in making the processes of communication and knowledge dissemination much more dynamic. This Lite Paper was written by the Company s technical staff. Qumu products allow organizations to easily create, manage, publish and distribute live and on demand video content while integrating the video with other media. Qumu solutions are engineered to allow companies to get started at minimal expense while leveraging existing IT standards and infrastructure. Qumu provides flexible deployment options: SaaS, enterprise software, and appliance delivery. Find out why so many Fortune 500 companies partner with Qumu for their enterprise video needs. www.qumu.com
Checklist for Choosing A CDN 1. Live Video CDN Requirements Live Video Flash Live Video Windows Media Multicast All of the above 2. Video On Demand (VOD) CDN Requirements VOD Video Flash VOD Video Windows Media Both 3. Multiple CDN requirements Enterprise Only Internet Only Both Enterprise and Internet 4. Number of Video Assets Less than 100 videos Between 100 and 1000 videos Over 1000 videos 5. Size of largest live broadcast 100 1000 participants 1000 5000 participants 5000+ participants 6. Number of locations Less than 10 Between 10 and 100 Over 100 locations