Network and Telecom Strategies Blog

WAN Performance Optimization for SaaS

Posted by: Eric Siegel

While I'm thinking about Software as a Service (SaaS) today, how about WAN Performance Optimization for SaaS?

Some SaaS websites are well-designed for the Web and perform well over poor bandwidth and high latency, but others don't, or they require the upload/download of large files. For those situations, WAN performance optimization can make the difference between usable and useless. (See, for example, my blog entry "Be a Hero! Cut costs to Zero!" for a discussion of optimization.)

Indeed, if you've created performance indicators in your service level agreement (SLA) with the SaaS provider, they may be more than happy to work with you to install WAN performance optimization between their server sites and your users. (See my blog entry "SaaS network performance SLAs.")

So. How should you install WAN optimization? There are a few things to keep in mind as you discuss this with your SaaS provider.

First, if your SaaS provider wants to use a double-ended appliance system (i.e., an optimizer appliance at the SaaS server site and an optimizer appliance at your site), how are you going to configure the device and integrate it into your branch offices? What happens if you have more than one SaaS provider? Will there be a tall, tottering stack of WAN optimizers from different vendors, and a maze of Ethernet cables plugging everything together? If the "appliance" at the branch office is a software application, how will you load it into your branch office server, and will it conflict with other software?

Second, if your SaaS provider wants to use a single-ended system (i.e., an optimizer appliance at the SaaS server site communicating with ActiveX, Java, or JavaScript running in a browser), then you have to be sure that your staffs' browsers will accept the plug-in, if necessary, and that it won't interfere with anything else.

Third, even if your SaaS provider doesn't want to install WAN optimization, you may still be able to improve performance with a branch office cache that will store commonly-downloaded files for use by all browsers in the office. Many branch office optimizers -- such as those that you might be using for communications with your central office -- can provide caches, as can Web traffic filtering devices, such as Blue Coat's ProxySG. Of course, there are also free caches, such as Squid; they can run on an inexpensive Unix or Windows box and make a big difference if you have a lot of users accessing the same set of Web files.

Final Catalyst WAN Performance Optimization Notes

Posted by: Eric Siegel

OK, two final notes on WAN Performance Optimization from the Catalyst Conference.

(By the way, I'll be rewriting my 90-page, hyper-boring paper "Optimizing WAN Performance" starting in a week or so; it should be published in a couple of months. Ask me if you need a draft copy sooner than that. And post a reply to this blog entry if you have any suggestions for me or for anyone about WAN performance optimization!)

FIRST, be sure to test using realistic user scenarios. Don't just rely on vendor promises or magazine articles or your buddy's experiences or some simple "drag and drop across the Windows desktop" copies! I've been saying this for years, but it really bears repetition.

The classical example is assuming that all vendors handle Microsoft's remote file access protocol, CIFS (or its latest Vista version, SMB 2.0) in the same way. They don't. And there's a difference between string-based compression (e.g., Riverbed) and Wide Area File Services (WAFS)-based compression (e.g., Cisco WAAS and Expand Networks). If you just do a sequential copy (e.g., drag-and-drop across the Windows desktop from a remote file share to your local disk), all of the CIFS systems look good. BUT if you open a file from INSIDE Microsoft Word, Excel, or some other application (is that what your users do?), then you'll see major differences. An application doesn't usually do only sequential reads and writes; it'll do "random" reads and writes within the file, and it'll create temporary files. So the intelligence of the WAN performance optimization solution becomes relevant: it can greatly improve performance when using remote file shares, possibly using the inherent caching ability of CIFS (i.e., the "oplock" capabilities), but it'll also be more complex and vulnerable to possible failure if the programming is sloppy.

SECOND, don't underestimate the impact of Web caching. Even major vendors, such as Microsoft, don't set their cache tags for performance. You can make simply astounding improvements in performance by setting Web cache tags appropriately, and your application front end (AFE) or load balancer can even do that for you. Be sure to include an "Expires" header, or most caches will not cache your pages, or they'll have to check back with the server to check the expiration status of every single object (unless you're using a specialized Web accelerator). See my Burton Group paper "Optimizing WAN Performance" and http://www.mnot.net/cacheability/, http://www.squid-cache.org/, http://www.web-caching.com/, and http://webmaster.info.aol.com/caching.html for more information. (Also look at http://developer.yahoo.com/performance/rules.html, which Nick Fiekowsky recommends, for more caching hints and general performance suggestions for the Web.)

Backup for WAN performance optimizers at remote offices

Posted by: Eric Siegel

(This is the first of a few blog entries that I'm going to post to share some ideas that came out of the Birds of a Feather (BoF) session on WAN performance optimization at Burton Group's Catalyst Conference this week in San Diego.)

A primary advantage of WAN performance optimization appliances is that they cut down the bandwidth needs of a remote branch office -- usually by 50% or more. And they reduce response time to make remote file shares, etc., actually usable instead of being a miserable, irritating experience that destroys productivity.

But what happens when the optimizer breaks? Bandwidth requirements spike upwards, and response time instantly becomes lousy.

My suggestions in the past involved QoS in the branch office boundary router to ensure that critical traffic would still flow despite the worsened bandwidth restrictions, and recommendations that the enterprise make arrangements with vendors or resellers to have spares available in-country (to avoid delays in customs and in transit) and configuration information available on a USB flash drive or by downloading as an email attachment. There would be a day or so of worse-than-normal performance as the compression directories are rebuilt, and then things would be OK.

But Nick Fiekowsky, while sharing his slides at the BoF, had a great idea: use the new software client optimizers, such as Blue Coat's Proxy Client, Cisco's WAAS Mobile, Expand Network's Mobile Accelerator Client, and Riverbed's Steelhead Mobile to serve as emergency backups. These software optimizers run on the users' laptops and provide the function of the optimization appliance. They're not as good, because (except for the new Expand Networks Mobile Accelerator Client! More later...) they don't share their compression directories and caches. But they're a lot better than nothing, and they also provide the ability for the user to use acceleration from home or on the road. This is especially great if the software optimizer system licenses are inexpensive or can be turned on and off easily from the central server location, with billing only when they're used.

My updated recommendation is therefore to install the WAN accelerator vendor's mobile client in branch office desktops. If the office's WAN accelerator fails, the desktop clients will step in to reduce WAN traffic and provide an acceptable user experience. It is necessary to have enough license capacity to cover all the client devices that may become active when a single branch office's WAN accelerator fails.

Be a Hero! Cut costs to Zero!

Posted by: Eric Siegel

Is there anyone who hasn't felt the threat of layoffs this last few months? Everyone is digging foxholes, worrying about the future. That's the natural tendency, I know. (Hey, I'm typing this from the warm security of my desk's kneehole, and my cats have gathered around me, prepared to show their fangs to anyone who might endanger their food supply.)

But if you really want to avoid Trouble, the thing to do is to get out there and save your company money, or set it up to make money quickly! Winning enterprises are using this period to prepare to launch at rocket speed out of the recession, leaving their foxhole-dwelling competitors chewing dirt and breathing rocket exhaust. And there's an easy way to help position your company for that launch, at the exact same time that you save megabucks immediately! It's called WAN Performance Optimization.

Yes, the same drum I've been beating for years, this time with extra added incentives!

I'll make this short, so we can all get back to work. But there isn't much to say.

ONE: WAN Optimization really DOES pay for itself in under a year. (In these times, payback in more than a year doesn't impress management at all. You need instant payback, and then big savings.) Those charts showing 50%, 80% and larger bandwidth savings aren't fake. In a surprising number of cases, the bandwidth savings are immense. So you'll be a hero for saving costs, and your procurement department will be singing your praises!

TWO: Your users will be delirious with joy at the performance improvements, especially if they've been suffering with remote file shares or with the pain of sending huge files back and forth among team members. Because it now takes only minutes, not hours, to send project files back and forth, there will be closer teamwork and they'll win more deals and avoid more screwups. Server centralization will be enabled, too, which is more money saved. So you're a hero for improving productivity and morale, and your HR and operations departments and your branch office managers and project managers will be singing your praises!

Just remember to forward all of those love notes to your management; this is not the time to be shy.

The technology can be somewhat complex, so be sure to find some reference accounts with a similar architecture and network design to yours. The vendors will love to show you around the technology, and they'll even loan you equipment to try it out. Different vendors specialize in different optimization situations; it's a good idea to look around. Some leading vendors are:

• Blue Coat
• Certeon
• Cisco (WAAS and AVS)
• Citrix (WanScaler and NetScaler)
• Exinda
• Expand Networks
• F5 (WANJet and WebAccelerator)
• Juniper (WX)
• Riverbed
• Silver Peak
• Stampede

See my previous blog entry, "WAN Optimization Whitelists and Blacklists"  for more information on this topic. Burton Group clients should look at my 80-single-spaced-page hyper-boring "Optimizing WAN Performance" report. And in a few weeks a new report, "Evaluating and Deploying WAN Performance Optimization," will be out in print. (Ask me for a pre-production copy.) It talks about how to pitch WAN optimization to management, how to select and evaluate contenders, and how to go through a rollout without crises. Or go to Burton Group's Catalyst Conference, July 27-31 in San Diego, where we're going to have tutorials and sessions on this, and a Birds-of-a-Feather meeting. Or call me for a free "dialogue." Gee, there are lots of ways to get started; no excuses here!

WAN Optimization Whitelists and Blacklists

Posted by: Eric Siegel

I've been working on a survey of best practices for acquiring WAN optimization solutions; it'll appear as a Burton Group paper and also be used as the basis for a talk at the upcoming Burton Group Catalyst Conference on July 27-31 in San Diego. It's been fun to talk to folks about what worked and what didn't work in their efforts to bring WAN optimization technology into their enterprises.

The papers and speech won't be out for another month or so, but meanwhile there's a very important point about this technology that I want to get out here: Yes, optimization is a fantastic way of saving money and creating really happy customers at the same time, but it doesn't work flawlessly for all applications.

The advanced dictionary-based compression component seems to be foolproof; it works and saves you, oh, 50% and up of your bandwidth at the same time that it usually makes a major improvement in performance that'll have the users loving you. So networking organizations that are primarily concerned with saving bandwidth expense and that dread having to work with users or application developers will usually choose optimization devices that are almost purely compression-based, and that don't fiddle much, or at all, with the protocols. They'll get a lot of performance improvement also -- especially if the same files are sent back-and-forth across the network with minor changes, or if they contain internal duplications, or if there's a lot of commonality among files -- and they'll never break an application, no matter how badly it's programmed.

But some enterprises really need the massive performance improvements that WAN optimization can provide for some common situations, such as access to remote fileshares using the Microsoft CIFS or Unix NFS protocols, or applications using SQL queries, or web browsers, or email. For those situations, fiddling with ("accelerating" or "spoofing") the underlying TCP, file, and application protocols can create simply unbelievable improvements in the performance seen by end users. But when the WAN optimization device starts interacting with protocols, some applications will break. It's almost never the optimization device's fault, because the optimizer engineers are experts in the protocols and carefully design their devices to squeeze every bit out of them without violating the protocol standards. But a surprising number of enterprise programmers don't know those standards very well.

The result is that protocol acceleration typically works flawlessly for broadly-used applications, such as access to remote fileshares by Excel, or use of web browsers, or SharePoint. But weird, custom-built client-server applications with embedded TCP socket calls that were built by overworked programmers under horrible deadline pressure who have no previous experience with TCP or other protocols? Well, that explains the "your accelerator broke my application" telephone calls. Truth is, the application was already broken, but its failures were usually rather rare and were attributed to "cosmic rays" or similar nonsense. When the optimizer starts really exercising the protocol, however, the breaks in the protocol become more obvious, and the irate telephone calls start.

And that brings me to the point of this blog entry: most enterprises quickly find that whitelists are wonderful tools for managing WAN optimization. They use whitelists to tell the optimizers which applications should be given protocol acceleration in addition to advanced compression. Applications that aren't on the whitelist are compressed, but their protocols are passed through the optimzers unchanged. At initial rollout, the network organization puts broadly-used applications, such as Excel, Internet Explorer and SharePoint, on the whitelist. Then, as time goes by, additional applications can be tested and added to the whitelist. By using whitelists, all of those weird applications that you didn't even know existed will not get into trouble. (By the way, organizations that try blacklists usually find that they have dozens, or hundreds, of applications that they didn't know about and that have mistakes in their use of TCP or other protocols. They find that out as a result of enraged telephone calls from the applications' users. Use whitelists instead.)

Some WAN optimization vendors have extensive deep packet inspection systems that can help in creating whitelists, but that's not truly necessary in all cases. Just filtering by IP address, hostname, or similar simple mechanisms may be all that you need.

So: don't fear optimization! You can save buckets of money and make your customers happy at the same time! But use whitelists when you do that rollout.