One of the biggest challenges facing IT today is overcoming the WAN bottleneck. Web traffic is exploding exponentially, making the once enormous T1 bandwidth feel like a dial-up modem. With $4-per-gallon gas, more and more workers are connecting to the corporate network from home, putting a greater strain on already-overtaxed network resources. Here are some of the underlying causes of the WAN bottleneck and a list of suggestions to improve network performance:
1. Identify your biggest sources of traffic.
Every network is different, so this step is essential. Most networks handle multiple sources of traffic. Remote users and PDA devices such as BlackBerrys create a steady flow of traffic to your network. Large attachments such as PDFs, CAD drawings and video files can also slow the network.
Wireless access points are notoriously poor resource managers, and large patch or application downloads can create network bottlenecks at inopportune times. In addition, unregulated users are surfing the web more frequently for shopping, social networking, watching YouTube videos or attending WebEx conferences. Hosted web services or remotely accessed databases, such as SharePoint or databases hosted by a Citrix Systems server, can slow the network with each additional user. VoIP is one technology that can save money and add functionality, but it can create a major bottleneck if the WAN cannot support it.
2. Create policies that can eliminate traffic.
User policies should be established so staff understand the limits on Internet use. Start by setting rules for what kinds of e-mail attachments should not be sent corporatewide. Game executables, nonbusiness PowerPoint documents, video files and audio files can create a network slowdown. Instead of sending business related e-mails with large attachments to large e-mail lists, suggest hosting the attachment on a website or intranet site and sending a link to the document instead.
The next set of rules should dictate what websites should be avoided. Audio-streaming websites such as Yahoo Music, social network sites such as MySpace, video websites such as YouTube, and file-sharing sites such as BearShare should all be avoided. Using firewall rules and content-filtering packages, many of these challenging sites can be eliminated.
3. Eliminate chatterbox apps and unnecessary ports and protocols.
By default, most network printers come with support for several protocols. Turn off unnecessary protocols and use the firewall to block ports you do not need. Check PCs for chatty applications. Use spyware-removal tools to eliminate chatty malware or spyware that may be installed with other applications. Run msconfig to see which applications are starting with Windows, and eliminate everything you can. Turn off auto-updates from Windows, Adobe and other applications. Use off-peak hours to manually push down Microsoft patches, antivirus updates and antispyware signature packs.
4. Prioritize traffic.
Use your router as a traffic cop. Give high priority to the most important data packets, such as VoIP — the VOIP packets must take precedence over an e-mail data packet. Quality of service will suffer if voice packets must wait for a data packet to transmit. Advanced switching can improve network speed and QOS.
5. Consider outsourced spam-filtering services and heavy-use applications.
Spam can create a huge amount of traffic on your WAN, so let a third-party vendor host your e-mail MX records and send you only relevant e-mail. This alone can increase your network speed dramatically.
Some applications may be better off hosted by a different vendor, rather than hosted at the central office. Take, for instance, a database or SharePoint application that clients, business partners and remote users will need to access every day. Rather than accept all this traffic into your network, have a third party host it. Placing applications onsite or offsite depending on workloads can create more bandwidth for other applications and services.
6. Choose security and backup solutions with WAN optimization in mind.
Security systems often add to the WAN bottleneck. Some systems scan packets for content filtering. This can take time, creating a slowdown, and may cause re-transmissions, which increase latency. Internet backup to offsite facilities should be done during off-peak hours. High-availability solutions such as Double-Take replication software can also reduce the amount of bandwidth if there are significant document changes on your local server. Always look for replication systems that can transfer the delta changes only, rather than the entire file, each time a file is altered.
7. Consider cache servers and thin computing.
When you have an offsite repository or two or more offices, you should build a solution to reduce bandwidth requirements as much as possible. Two options are cache servers and thin computing.
If a remote office is big enough and your budget will support a server setup identical to that in your main office, having duplicate hardware that acts as a document cache is ideal. You can use Interwoven document-management cache servers to replicate all the documents from both offices, so there is a copy of all the documents on both servers. This is a good idea because if the connection ever fails, the remote office can still work. Even on a normal day, the cache server will reduce over-the-wire requests for documents from the remote site because the requests will be made locally.
Thin computing is a popular option and can be a cost saver for remote solutions. If you centralize your hardware in a data center or have a smaller remote office to open up, having a Citrix server that can deliver access to your central server may be the best option. Citrix reduces bandwidth requirements for user access because it transmits only mouse clicks, keyboard clicks and an occasional screen refresh.
The one caveat is printing, because a printing job must transfer the packet to the printer closest to the user, which can cause a bottleneck if the volume is heavy.
WAN applications from Citrix, Cisco,Blue Coat and Silver Peak can reduce Internet traffic by 25 percent or more.
8. Separate network resources.
One way to achieve WAN acceleration is to redirect chatty or heavy resources to an alternative Internet pipe. Wireless and videoconferencing systems are perfect for putting on a separate Internet connection.
Wireless systems are chatty devices and videoconferences can be bandwidth cows. By giving these processes their own Internet
connection, you can increase security and the bandwidth for your main network simultaneously. Also, you have the option to put special users — such as coders who need access to a hosted Internet application and do not need access to your network resources — on this separate Internet pipe so they don’t create heavy traffic on your main network. Some firewalls let you redirect certain types of traffic to an additional Internet pipe, leaving more room on the main pipe for essential traffic.
9. Consider WAN acceleration hardware.
WAN acceleration products use a variety of methods to dramatically reduce traffic. For point-to-point traffic, two accelerators can compress typical traffic so it can travel the line more efficiently. Accelerators use protocol spoofing to look for similar traffic that they can then bundle and send out more efficiently. Caching web pages reduces the number of Internet requests because users are accessing the stored cache on the local network for repeat requests.
Consider the network that many users use to access CNN news. The first time someone accesses the CNN site, the accelerator fetches the page and then stores the information in its cache. The next 10 requests access the cache and don’t hit the Internet at all.
With accelerators you can apply limits to a user’s available pipe, preventing Internet hogs from causing gridlock. You can also apply rules to eliminate or prioritize requests from certain web applications. Useful reports can also give you insight into where your traffic is coming from and may lead to much better usage policies.
10. Add more bandwidth.
The cost of bandwidth has dropped dramatically. Aggressive DSL prices have forced the cost of copper connections down. Fiber and wireless Internet network options now let corporations add fat pipes and redundant bandwidth for a fraction of the cost in years past. It is now common to see T1s offered for as low as $500 a month.
Wireless connections use line-of-sight technology to push traffic from building to building without accessing the central office. This allows for aggressive pricing because the Internet provider doesn’t need to pay central-office prices.
Chris Cardillo is director of technology for Kozyak Tropin & Throckmorton, a law firm based in Miami, Fla.