Wide Area Networks, or WANs, are common in large organizations with multiple locations. A WAN allows network connectivity between each site and can allow, for example, users on one site to use resources located on another site. Unfortunately, WANs don’t always offer the level of performance users expect. They often have limited bandwidth and can easily get congested. To improve performance, two main options exist: Increasing bandwidth or optimizing. The price of increasing bandwidth is often prohibitive, leaving optimization as the only viable solution. Today, to help you see clearly through the maze of optimization products and solutions available, we’re having a look at some of the best WAN optimization tools.
Since we can’t assume that everyone has the same knowledge of WANs, we’ll start off our discussion by explaining what they are and, more importantly, why they often suffer from performance degradation and slowdowns. Then, we’ll talk about optimizing WANs. We’ll tell you what it means, why you should do it and how it can be done. We’ll finally be ready to introduce the best tools for WAN optimization. We’ve picked five of the best and most reputable ones and we’ll briefly review each of them, discussing their main features, advantages, and drawbacks.
Wide Area Networks In A Nutshell
Networks started as a local thing. Early networks were intended to connect several computers in a small business to share resources. For instance, all interconnected computers could use a common printer connected to one of them. To differentiate them from large inter-university inter-networks, they were called Local Area Networks, or LANs. They were essentially peer-to-peer installations where multiple computers shared their resources. It eventually became common practice to dedicate one of the computers—usually the most powerful one—to provide its resources to its peers. The server was born.
Larger organizations with multiple sites soon saw an advantage in interconnecting their various locations. It would allow for easy transfer of documents from one site to the other and could even allow for centralized servers, with smaller office having only workstations that use resources from a remotely located server. These networks became known as Wide Area Networks or WANs.
In simple terms, a WAN is simply a bunch of LANs interconnected together. Now this interconnection can be done in several ways. In the beginning, serial communication over telephone lines using modems was used. Then data transmission services became available in the form of ISDN and then broadband services. Each evolutionary stage typically provided more bandwidth and lower prices.
Causes Of WAN Performance Degradation or Slowdowns
Performance degradation is common with WANs and it is usually reported by users as slowdowns. Users will complain that it takes forever to open a document located on a remote server whereas opening a local document is quick.
There is one single cause which accounts for probably 99% of all WAN performance degradation issues: network congestion. Network congestion is exactly like traffic congestion. WAN circuits, the physical links that interconnect various locations all have a certain capacity. And that capacity is limited. You can think of a WAN link as a highway between two cities. It too has a limited capacity. A five-lane highway can obviously carry more traffic than a two-lane one. And what happens when the amount of traffic exceeds the road capacity? Traffic jams. Well, congestion is the traffic jam of networks.
WAN circuits are usually expensive. Very expensive when compared to LANs. For that reason, organizations typically install the smallest circuit that will suit their current needs. But, just like disk space, network bandwidth is something you always need more of. Eventually, most WAN circuits will become congested. When that happens, two options are available: increasing the circuit’s capacity or optimizing its usage. Optimization, you would have guessed, is what we’re interested in today.
WAN Optimization: The What
In one sentence, WAN optimization is simply making the best use of the limited available resources of a WAN circuit. Concretely, this could be achieved in several ways. In its most basic form, optimization can be achieved through regulating usage. An organization could, for instance, have a usage policy that forbids sending emails with attachments bigger than a certain size or using the Internet for personal purposes.
Another typical way that WAN circuits can be optimized is through data compression. You can think of it as zipping the data before sending it over the WAN. Modern compression algorithms can achieve impressing compression ratios, greatly reducing the required bandwidth.
Traffic shaping is another popular optimization method. Traffic shaping simply means the prioritization of certain traffic that is considered more “important” over other traffic which is less. For instance, an organization could decide to give high priority to traffic related to its ERP system and low priority to Internet browsing.
We’ll soon see how these optimizations can be implemented but first, let’s have a look at why optimization is useful.
WAN Optimization: The Why
While the obvious solution to WAN performance degradation seems to be to increase the bandwidth, it might not always be the best option. There are several reasons for that. First, bandwidth is expensive. In fact, it can be very expensive. Imagine a WAN connection that uses a technology that is already used to its maximum capacity. Increasing bandwidth, in this particular situation, would entail replacing the circuit with a different technology.
Another important reason not to increase bandwidth is that it is only a temporary measure. Eventually, you will run out of bandwidth again and will have to start over. In the long run, there is no way this can be economically sensible.
Bandwidth optimization, on the other hand, is relatively inexpensive–especially when compared to frequent bandwidth increases–and most of the time very scalable. You can deploy some optimization technology today and gradually apply more and more bandwidth-saving features as your utilization increases. In the long term, it seems clear that optimization will serve you better.
WAN Optimization: The How
There are several ways that bandwidth can be optimized. Let’s briefly review the main ones. The first technique is called deduplication. It works by eliminating the transfer of redundant data at the byte level and by sending references instead of the actual data. Compression is similar to deduplication but relies on data patterns that can be represented more efficiently. The technique is similar to the compression of files but it is applied on-the-fly by optimization systems.
Caching and proxying are two techniques that rely on human behavior to achieve optimization. If, for instance, it is observed that the same chunk of data is transferred multiple times, it makes sense to keep a copy of it where users need it rather than fetching it over the WAN each time.
Traffic shaping is another common technique used for WAN optimization. The idea here is to control the data flow for specific applications. It gives administrators the power to determine which applications take precedence over others. It is commonly used to prevent one protocol or application from hogging all the available bandwidth. Some traffic shaping systems can also optimize traffic on a per-user basis in addition to per-application. Prioritization is achieved either by using multiple queues with different priorities, by reserving part of the bandwidth for priority traffic, or often a combination of both
Finally, latency optimization is yet another way that WANs can be optimized. Latency optimization is a broad term which can include TCP window size scaling, selective acknowledgments, or layer 3 congestion control algorithms. Co-location strategies where applications are moved closer to their users is also a form of latency optimization, albeit a manual one.
The Best Tools For WAN Optimization
Several of the best-known vendors of networking equipment have solutions for WAN Optimization. We’ve explored the market trying to find some of the best solutions. Most of the solutions in this field are hardware appliances as they often provide the best combination of functionality and performance. The various solutions are listed in no particular order as it is impossible to rank them against one another.
Our first entry is not an optimization tool per se but we’ve decided to include it as it is a tool that you should probably install before you even start thinking about WAN optimization. It is a bandwidth monitoring tool. You can use it to monitor bandwidth utilization on all your WAN circuits. This will enable you to better plan the deployment of your optimization efforts and also to measure their effectiveness.
SolarWinds is a well-known name in the network administration field. The company has been making some excellent tools for years. It is also known for its free tools that address some specific needs of network and system administrators. Its free Kiwi syslog server or subnet calculator are among the most popular.
The Network Performance Monitor, or NPM, is SolarWinds’ flagship product. This is a network monitoring platform that uses the Simple Network Management Protocol to poll network devices, read their interface’s bit counters, compute bandwidth utilization, and display it on graphs depicting their evolution over time. In the context of bandwidth optimization, it’s an excellent tool to evaluate and measure the current baseline. Comparing it with the post-optimization measurements will provide a quantitative and objective evaluation of the improvement.
NPM features a user-friendly GUI interface that administrators can use to monitor devices and to configure the tool. Talking about configuration, adding a device is just a matter of specifying its IP address and SNMP community string. The software also has some very useful alerting features that can automatically notify you when something abnormal–such as a circuit going down or utilization exceeding a predefined threshold–happens. NPM is easily scalable from the smallest networks to large installations with hundreds of devices spread over multiple sites.
Price-wise, the SolarWinds Network Performance Monitor starts at just under $3 000 and varies according to the number of devices to monitor. A free 30-day trial is available from SolarWinds so you can try the product to make sure it fits your need.
2. Riverbed Steelhead SD
The Riverbed Steelhead SD appliance is arguably one of the best solutions out there. Its immense popularity partly stems from the fact that it proposes a set-and-forget approach to optimization. Riverbed claims the device can be set up in fifteen minutes. Once the devices are installed and configured behind the routers at each end of a WAN circuit, they immediately start optimizing traffic.
The Riverbed Steelhead SD uses several powerful technologies to accomplish its feat. First, the device uses a form of compression where multiple packets are compressed into one, thereby reducing the latency. The system also uses data referencing which is a type of deduplication. This is an “intelligent” process that can achieve speed improvements of 60% to 90%. Transaction prediction is another way the Riverbed Steelhead SD can optimize WANs by predicting what users are about to do. For example, if a user clicks on a file name, chances are he will download it. The appliance will, therefore, start downloading it right away.
3. Blue Coat PacketShaper
The Blue Coat PacketShaper, now from Symantec after they acquired Blue Coat a couple of years ago has been optimizing WANs for almost 20 years. It is by far one of the best-known WAN optimizing solutions You’ll get from the name that the main technology it uses is traffic shaping.
The Blue Coat PacketShaper will easily identify all business and cloud applications, and application traffic. It provides easy-to-deploy policies for managing application traffic. It can guarantee bandwidth for critical applications while prioritizing them. Of course, that bandwidth guarantee comes at the cost of other non-important or disruptive traffic that the PacketShaper will constrain.
The PacketShaper provides a full 360° view of the network and it monitors the network traffic on all ports and protocols. The PacketShaper reports provide insights on application and user behaviors that can impact network performance or integrity. Furthermore, its built-in reporting feature delivers pre-configured reports for a quick overview of important network statistics.
4. Citrix NetScaler SD-WAN
Citrix claims that the NetScaler SD-WAN is the only one to combine proactive application traffic management, end-to-end QoS, routing, and WAN optimization. The system’s goal is to deliver a better branch office user experience for SaaS, enterprise, and virtual desktop applications. It can help lower network costs, simplify remote office networking, and provide visibility into application performance.
The NetScaler SD-WAN uses data compression and deduplication for faster app performance. It also supports a broad set of acceleration protocols, including industry-leading HDX acceleration for faster application delivery. The system offers centralized policy definition and integrated WAN Optimization configuration which makes building a software-defined WAN intuitive and simple. It also features dynamic routing which learns about network changes and can it be deployed as a branch WAN router.
This system is also a great security appliance. It has an integrated application-aware firewall, making it simple to deploy centralized firewall policies. With its built-in encryption and tunneling capabilities, it doesn’t require the use of a VPN to establish remote office connections over the public Internet.
5. Cisco Solutions
Cisco is certainly the best-known name when it comes to networking. And with the broad portfolio of solutions the company offers, it’s no surprise that it includes WAN optimization. In fact, Cisco has a whole range of products and solution to address WAN optimization. Let’s see what they are.
First, there is Cisco SD-WAN. This solution works by selecting the most efficient link for each application. You’d typically use it in a remote office that has a WAN link and an Internet circuit. Cisco SD-WAN could then automatically route unimportant traffic through the Internet, leaving the WAN available for business-critical applications.
As good as Cisco SD-WAN is, it does not directly address latency, jitter, and packet loss introduced over the WAN. Cisco WAAS uses a combination of techniques and application acceleration features to overcome the most common challenges associated with transporting traffic over a WAN. It applies per-application protocol acceleration and caching techniques to WAN traffic flows, making sure your apps operate properly. Cisco claims that WAAS will make “applications operate over the WAN as well as they do over the LAN”.
WAAS can also be combined with cloud caching services from Akamai—a leader in content distribution—and deliver optimization by “extending the Akamai Intelligent Platform directly into your branch router.” Furthermore, all the Cisco solutions can be centrally managed, monitored, designed, and configured using Cisco DNA Center and Virtual Central Manager for WAAS.
6. Silver Peak NX & VX
Silver Peak offers several solutions in the Software-Defined WAN, hybrid WAN, and WAN optimization and acceleration field. Its NX WAN optimization appliances sit between network resources and the WAN infrastructure and let you overcome network bandwidth, distance, and quality challenges when moving application data over the WAN.
The Silver Peak NX appliances do not require any client, server, or application reconfiguration to operate. These devices are the industry’s highest-performance WAN optimization devices according to Silver Peak. Devices are available for the smallest branch office to the huge data center, supporting up to 5 Gbps of WAN bandwidth and 512 000 simultaneous flows. The system is also available in a virtual form as the Silver Peak WX which can run on virtually (pun totally intended) any hypervisor.
No matter what solution you choose, all the products reviewed here will provide excellent value. And a monitoring solution such as the SolarWinds Network Performance Monitor will help you with the planning phase of your deployment and allow you to demonstrate the improvements. There might be several reasons why you choose to optimize your WAN but in the end, the biggest advantage of WAN optimization is that users of your network will benefit from the best possible experience.