As storage and networks become more intertwined and interdependent, storage administrators will increasingly be...
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called upon to decide where best to place certain types of files, especially streaming media and e-learning training programs. The closer these files are placed near users, the better the performance, which makes for a happier user. For large corporations with dispersed work forces, caching dynamic content at the network's edge, as part of a broader enterprise content delivery network (eCDN), is becoming a popular storage option for not only performance, but economical reasons as well.
|Is an eCDN the right storage solution?|
"It's caching on steroids," says Stephen J. Elliot, research director, storage and enterprise management, Hurwitz Group, Cambridge, MA.
Fueling the move to eCDNs are bandwidth limitations and latency issues that enterprises face as they move to Web-enabled applications such as streaming media, e-learning and global corporate communications. "Until recently, anyone that played around with streaming media probably got slapped on the nose with a rolled up newspaper from the IT department because there just wasn't a good way to handle big files integrated into Web pages," says Julie O'Brien, product manager of content networking, Cisco.
Today, storage and network administrators need to work together to answer the question: "What should be stored at the edge of the corporate network?" says Lucinda Borovick, program director Data Center Networks, International Data Corp., Framingham, MA.
eCDNs strategically cache Web-based content on the enterprise network edge, so that every content request doesn't have to traverse the WAN. With most-requested or prepositioned content available on the LAN instead, that increases bandwidth efficiencies, delivers requested content faster, enables streaming content transfer and saves on related costs.
Results can be dramatic. Logitech International, Fremont, CA, needed to boost operational efficiencies with enterprise resource planning (ERP) applications at its foreign subsidiaries. An eCDN with edge caching fit the bill, and slashed transaction processing times by up to 50%, according to Pierre-Olivier Monnier, CTO.
For example, at the company's factory in Suzhou City, China, 500 to 800 workers log onto the network every morning during the same 15-minute span. The process used to take up to 70 minutes, depending on bandwidth availability. Now with an eCDN from Network Appliance that includes NetCache appliances caching on the LAN, it now takes just two minutes, Monnier adds. And it took Logitech just six months to recoup the $200,000 it took to install the system in 15 global facilities.
Caching is about performance--anticipating the next content request and retrieving it before a command is issued, says Bob Zimmerman, director storage research, Giga Information Group, Cambridge, MA. "Think of the operating room nurse who has the right instrument in the surgeon's hand before he asks for it because she has been through the process before," says Zimmerman.
Caching is just one element of an eCDN. According to Gartner, the basic components of an eCDN include:
Caching. To store frequently used or prepositioned content to improve end-to-end performance. It can be local (proxy caching) or adjacent to the content server (server-side cache or reverse proxy caching).
Content management. It's essential to keep content up to date and synchronized between storage locations.
Content redirection (sometimes included in the cache): To route the request for the content to the most appropriate location--can be local or global or both.
Optional eCDN components include load balancing to balance the load among content origin servers, external content caches or external redirection devices.
An eCDN basically is a network storage product that lets enterprises combine local network storage with any kind of network bandwidth--especially WAN bandwidth--to deliver "the right content in the right format at the right place at the right time," says Jim O'Toole, chief technologist, content networking, Cisco.
ECDNs are an extension of--or a replacement for--existing proxy/caches in corporate networks, says Thomas Mendel, Giga analyst. "They enable the scheduled distribution of Web content and rich-media files to branch office caches during off-peak hours. Once content is in the remote caches, eCDNs enable the management of the content from a central location. Current eCDNs include some rudimentary bandwidth management, but are quickly evolving to include additional capabilities such as the ability to serve live and on-demand events," he adds.
Frank Russell Co., located in Tacoma, WA, wanted to simplify and expand its caching capabilities. The global investment services company used a Microsoft Proxy 2.0 for Windows NT 4.0 in conjunction with a Microsoft Internet Information Server 4.0 that could do some caching. But the company continuously ran into limitations from the layered environment that took multiple administrative workarounds such as entries in firewall or browser proxy exception lists.
With audio streaming, for example, if 10 people requested the same stream at the same time, each needed a separate WAN connection because the audio streaming wasn't buffered. And even though Russell has a big pipe to the Internet, the cost depends on usage.
With the company's migration to Windows 2000, the Frank Russell Co. went shopping for an alternative, settling on an eCDN solution from CacheFlow, Sunnyvale, CA. The CacheFlow 600 Series Client Accelerator--an integrated hardware/software solution--allows the company to store all filter, route and configuration scripts on a local Web server for easy maintenance and to automate the ability to centralize the collection of proxy logs for better forensics and analytics and allows the application of emergency filters to Web traffic in case of viruses or Trojans.
CacheFlow buffers streaming audio locally on the proxy server, allowing multiple people to pull the same archived stream faster. It also uses a splitting function for live streams, enabling objects to be written straight to disk, boosting performance.
Siemens Medical Solutions Health Services Corp., a Malvern, PA-based ASP had a three-fold reason for wanting an eCDN with edge caching capabilities. The company wanted to:
- Accelerate content delivery to its customers, and delivery of Internet and Intranet content to its employees.
- Implement a video streaming solution for customer demonstrations at its executive briefing center in Malvern.
- Provide the foundation and scalability for enhanced corporate communications and e-learning at the desktop.
With its $50,000 to $80,000 edge investment that includes content caching with Cisco Content Engines, Siemens saved 50% on server size, cut content distribution costs, boosted network performance and added redundancies, says Powers.
An eCDN with edge caching was a no-brainer for Merrill Lynch Canada. The financial services giant needed a cost-effective way to distribute huge research reports to its more than 100 dispersed offices. Traditionally, that meant replicating huge data files to storage devices in the remote offices, a labor-intensive task. Often the updates would have to be sent via overnight mail because some offices were not Web-enabled, or if they were, there were bandwidth issues with real-time data transfer, says Amit Pandey, senior director of NetCache for Network Appliance. Some offices could only connect to the WAN at 128Kb/s, and though the existing proxy server could do some Web caching, it couldn't handle streaming media.
Now with its eCDN, to reduce network traffic on the WAN, Network Appliance's C1100 NetCache appliances are installed in each remote office. Larger C720 appliances are in the Toronto data centers to load balance network traffic, cache Internet content inside the corporate firewall and act as parent caches to the C1100s. With the NetCache, the company can deliver all major streaming formats. Content also can be prepositioned before users request it, allowing files to be sent over the WAN at night to keep the network free during the day.
eCDNs, however, aren't the answer for everyone and there can be issues with their implementation. Installing an eCDN--especially at large, distributed companies--takes a huge effort, including planning, rollout and ongoing management. In addition, many enterprises today also view the applications that caching enables--Internet acceleration, streaming media-based corporate communications and e-learning applications as nice to have, but not mission critical must-haves, says Lawrence Orans, Gartner analyst.
There's no need to convince Logitech's Monnier of the value of an eCDN. Says Monnier: "It was one of the best investments that we have made ... the one that made the biggest difference for an enterprise user."
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