Applying the Tools
If you’ve done any research, you know the WAN optimization market is crowded and competitive, with vendors deploying a confounding array of technologies. Navigating the market and choosing the right product is a growing challenge. The WAN optimization market has seen double-digit annual revenue growth with annual unit shipments doubling since 2007.

VistaOne has adopted the mission of helping organizations strain out the hyperbole and misinformation and make choices tailored to solving the issues and meeting the needs of their specific WANs.

WAN optimization products seek to accelerate applications via eliminating redundant transmissions, staging data in local caches, compressing and prioritizing data and streamlining chatty protocols. WAN optimization also helps avoid packet delivery issues common in shared WAN environments like MPLS and Internet VPNs.

Component techniques of WAN optimization can include deduplication, WAFS, CIFS proxy, HTTPS proxy, media multicasting, Web caching, Forward Error Correction (FEC) and bandwidth management.

Deduplication eliminates the transfer of redundant data across the WAN by sending references instead of the actual data. By working at the byte level, benefits are achieved across IP applications.

Data Compression, or packet shaping, works by eliminating the redundancy from a stream of packets. The compression algorithm looks for patterns in the data stream and replaces redundant information with a small code that can be transmitted more efficiently than the raw data.

Compression usually happens at the router and may be hardware or software based. With software based compression, the router's CPU applies a compression algorithm to the outbound packets. If compression is hardware based, compression tasks get offloaded to a dedicated chip, freeing the router's CPU from compression-related overhead.

Caching, or proxy, allows remote users to access centralized applications as if they were local by caching parts of the file system.

As an example, imagine that someone sends a message with a large attachment to everyone in a branch office using Microsoft Exchange. Even though Exchange Server uses single-instance storage for messages, the attachment would have to be downloaded over the WAN link each time someone in the branch office opened the message. With a caching solution, the attachment would be cached so it wouldn’t need to be sent repeatedly over the WAN link.

Protocol Spoofing bundles multiple requests from chatty applications into one. In most cases, a modem or router simulates ("spoofs") the remote endpoint of a connection to a locally attached host, while using a more appropriate protocol to communicate with a compatible remote device that performs the equivalent spoof at the other end of the communications link.
TCP connections may suffer from performance limitations due to insufficient window size for links with high bandwidth x delay product or on long-delay links like those over GEO satellites. TCP's slow-start algorithm significantly delays connection startup. A spoofing router terminates the TCP connection locally and translates the TCP to protocols tailored to long delays over the satellite link like XTP.

Traffic Shaping or bandwidth shaping controls data usage by spotting specific patterns in the data and allowing or disallowing that traffic. You can limit the amount of bandwidth consumed by a user or by an application, usually by enforcing established policies. There are a lot of traffic-shaping products that throttle traffic based on IP address, MAC address, network subnet, or service type. Some products also segment bandwidth based on a packet's source and destination addresses.

Quality of Service is similar to traffic shaping but where traffic shaping mostly limits bandwidth usage, QoS permits a user or application to reserve bandwidth to guarantee that it will be available when needed.

Normal network links use only a best-effort packet delivery. If the link is congested with traffic, packets will be slow to reach their destinations. Using QoS, you can define bandwidth requirements for users or applications in either absolute or relative terms (10 Mbps or 10% of the total available bandwidth, for example).

You can control the following network properties for a network that supports QoS:

• Throughput (total bandwidth reserved)
• Priority
• Latency
• Packet loss and retransmission

Route Optimization, commonly referred to as smart routing or route control, boosts multi-homed networks. Multi-homed networks means that, rather than have a single WAN connection, an organization can have multiple WAN connections that accomplish the same task.

For example, rather than having a single WAN connection to an ISP, a company might have several WAN connections to a single ISP or to multiple ISPs. Smart routing, or route optimization, comes into play when a company can actively control how traffic is distributed among the various WAN links.

An enterprise with a multi-homed Internet connection ordinarily uses a protocol called Border Gateway Protocol (BGP) as the engine responsible for making Internet routing decisions. Unfortunately, BGP can detect a route failure but cannot detect a brownout. Brownouts are far more common than total link failure. The nearsighted BGP therefore routes users' packets over the semi-capable link, inevitably leading to complaints.

Route optimization technology monitors all of the available external links in real time and routes packets accordingly. A route optimization solution looks at things like the link's latency, stability, performance and cost when making routing decisions.

Application Acceleration is really a collection of technologies. The main components of any application acceleration appliance are SSL encryption and compression offloading. Encryption and compression require that the processor do a mountain of calculations.

An application acceleration appliance takes on these tasks, freeing the processor to spend more time on higher priority responsibilities. Application accelerators also typically incorporate caching and load balancing.

Equalizing or load balancing makes assumptions on what needs immediate priority based on the data usage. As the name implies, equalizing distributes traffic evenly across multiple networks to avoid saturating any one WAN link. Even distribution of traffic across the available links ensures that each link operates in the most efficient manner possible.

You can categorize load balancing as either inbound or outbound. Inbound load balancing benefits organizations that receive a lot of requests from the Internet, like organizations that host their own Web or mail servers. Outbound load balancing best serves users that need to upload large files or send out large quantities of email.

An added benefit, load balancing supports fault tolerance. If one of the links fails, traffic can continue to flow through the remaining link until the failed link has been restored.

Connection Limits prevent access gridlock in routers and access points. Often overlooked as a source of network congestion is the number of connections a user generates. A connection can be defined as a single user communicating with a single Internet site.

When you access the Yahoo home page, for example, your browser goes out to Yahoo and starts following various links on the Yahoo page to retrieve all the data. Often, this data is not all at the same Internet address, so your browser may access several different public Internet locations to load the Yahoo home page, perhaps as many as ten connections over a short period of time. Routers and access points on your local network must keep track of these "connections" to insure that the data gets routed back to the correct browser.

Although ten connections to the Yahoo home page isn't excessive over a few seconds, there are some very poorly behaved applications, (most notably Gnutella, Bear Share, and BitTorrent), that are notorious for opening up hundreds or even thousands of connections in a short time period. Make sure any traffic management deployed incorporates some form of connection limiting features.

Simple Rate Limits prevent each single user from getting more than a fixed amount of data. This involves putting a fixed rate cap on a single IP address as is often is the case with rate plans promised by ISPs to their user community.

Take for example six users sharing a T1. Assume each of these six users gets a rate of 256 Kbits/s up and 256 Kbits/s down. Then these six users each using their full share of 256 kilobits per second is the maximum amount a T1 can handle.

It’s unlikely that you’ll hit gridlock with just six users. When the number of users reaches thirty, gridlock becomes likely, and with forty or fifty users, it becomes a certainty to happen quite often. It is not uncommon for schools, wireless ISPs, and executive suites to have sixty users to as many as 200 users sharing a single T1 with simple fixed user rate limits as the only control mechanism.

Unless your network is not oversold there is never any guarantee that busy-hour conditions will not result in gridlock. This option is best suited as a stop gap first effort for a remedying a congested Internet connection or WAN link.

Had Enough?
You could use a partner that eats, sleeps and breathes this stuff to guide you to proper choices, or at least arm you with the necessary facts. Contact VistaOne for consultations, evaluations, innovations and transformations without reservations.