Exinda last week introduced a cache for HTTP video into its products in a software update that also aims to boost performance and support for IPv6. The company's product, in addition to the integration with WAN optimization, differs from the enterprise video products offered by other vendors such as Cisco in that it's aimed specifically at Web-based video, with public Internet sites particularly important.
"What we've seen is that somebody will see something really funny on YouTube, then send a note saying 'Hey, you gotta see this!' You get this viral effect," Kevin Suitor, Exinda vice president of marketing, said in an interview. "We see it a lot in the morning and just after lunch." By storing a local copy of the video on a cache within the Exinda appliance, he said that total bandwidth consumption is reduced by 30% to 80%.
Called Edge Cache, the system works by recognizing content itself rather than just Web addresses, so it works with dynamic URLs, though not sites that encrypt video traffic. Unlike most of the techniques in WAN optimization, caching is asymmetric so only needs to be installed at one end of the link, meaning that it can support most major streaming sites such as Amazon and Brightcove. The big exception is Netflix, something Suitor said is due more to fear of violating copyright law rather than technical issues or lack of demand.
Caching large files at the network edge isn't a new idea, of course, and it's one that's been enjoying a resurgence of late thanks to enterprise video. Last week, Cisco launched its Enterprise Content Delivery System, a product that aims to help enterprises build their own Akamai-style content delivery systems. However, this is aimed largely at internal enterprise video broadcasts for purposes such as training. Exinda thinks Internet video has broader applications.
"A year ago, I would have called YouTube pure social, one of those things you need to build tools to avoid," said Suitor. "But increasingly, companies are using it as a business tool; it's a very cost-effective way of distributing things around the world." Enterprises that blocked YouTube or tried to work around it would have missed out on this potential.
Although Edge Cache is broad in the applications it targets, it is narrower in the technology it supports, only working with Web-based (HTTP) video. The Cisco system supports a wider variety of protocols, and also lets network managers control things like the timing of videos--for example, pushing content out in advance of when it is needed at times when bandwidth consumption is low. A potentially bigger weakness is that no kind of caching can work with videoconferencing or voice over IP applications like Skype, as these depend on live, two-way traffic. While some vendors such as Silver Peak do apply WAN optimization to real-time traffic, their techniques involve prioritization and don't reduce the bandwidth required.
Exinda is adding Edge Cache to its existing WAN optimization hardware as part of its ExOS 6.1 release, which also adds other features aimed at improving performance. The most important is that its processes are now split into a greater number of threads, letting the software take full advantage of the multiple processor cores already in its hardware. This increases the number of concurrent optimized TCP connections that the box can support, giving it what Suitor claims is the industry's lowest cost per session. Based on list prices, he says this ranges from $30 on the smallest box to $1.28 on the largest.
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