This transcript is from a PodTech.net podcast at:
http://www.podtech.net/home/technology/1580/the-myth-of-bandwidth-and-application-performance

Host: Michael Johnson - PodTech
Guest: Ameet Dhillon - F5 Networks

Michael Johnson - PodTech
This is Michael Johnson, and joining me on the Podcast today is F5 Networks' Ameet Dhillon who is the Director of Product Management for Secure Remote Access and WAN Optimization Solutions, Ameet welcome to the Podcast.

Ameet Dhillon - F5 Networks
Glad to be here Michael.

Michael Johnson - PodTech
Today we're going to talk a little bit about the Myth of Bandwidth and Application Performance, and the first question I have to ask you Ameet is, what are some of the major factors that negatively affect Application Performance across a Wide Area Network or a WAN?

Ameet Dhillon - F5Networks
Well, there are variety of them but I think the key ones for people to be aware of are -- and are divided into sort of a network level problems, and the application level. So, at the network level it's typically things like Latency and Packet Loss, and at the application level, it tends to be what we call or refer to is 'chatty protocols' and an example of a chatty protocol is CIFS.

Michael Johnson - PodTech
What about adding more bandwidth, will that solve the application problem?

Ameet Dhillon - F5 Networks
No, actually contrary to what a lot of people believe or certainly is very prevalent in the minds of network engineers, adding bandwidth will typically not solve the problem. There is one case where it would, and that would be if your problem is actually the fact that the link you have from your enterprise into the Internet is actually the bottleneck and that tends to not be the case most of the time, the vast majority of times, the issues that you run into that are affecting application performance are as I mentioned before things like Latency or Packet Loss in the network, meaning not your connection into the network or as I say application level protocols which are very chatty, and for those specific problems, which in the vast majority of the time, Application Performance is degraded by those problems, adding more bandwidth contrary to what people may think is simply not going to help.

Michael Johnson - PodTech
Okay, let's back up a little bit, can you describe what latency is, and how it causes Application Performance problems?

Ameet Dhillon - F5 Networks
Sure, so latency is probably one of the key factors in causing application problems across a Wide Area Network, and so simply put latency is the delay that occurs when a packet is sent to a server on the other end and returns. So, it's typically measured in round-trip time, in other words the amount of time that it takes for a packet to go across to its destination and make it back. And so a simple way for sort of more technical folks to get a rough idea of what latency is, if you've ever used the command Ping, and you ping yahoo.com for example, you will get a reply back. The ping will give you a reply back, which will show you roughly what the round-trip time was for that packet to go to the Yahoo! servers and come back. And just to give people a sense of how latencies are measured and what sort of typical latencies might be. So East Coast to West Coast in the United States, typical latencies there are sub 100 milliseconds, and latencies are typically measure in milliseconds. So, 70-80milliseconds is fairly typical East Coast to West Coast, so San Francisco, Los Angeles. From the United States to Asia, instead of China or India, 300 milliseconds plus is fairly typical. From the US to Europe again depends where the United States but 150-200 milliseconds is fairly typical. And across a satellite (Inaudible) are still commonly used a 100 milliseconds plus or a second plus is not uncommon at all.

Michael Johnson - PodTech
Okay, how can F5 decrease latency across a WAN and as a result improve application performance?

Ameet Dhillon - F5 Networks
Well, so theoretically speaking no one can decrease latency because it's a physical property and it's just due to the speed of light and distances that has to be traveled. So, theoretically not possible to decrease latency as such, otherwise (Inaudible) will be defying the laws of physics. However, having said that it is very possible to mitigate the effects of latency.

Michael Johnson - PodTech
Yeah, what are chatty applications, you've mentioned that before and how do they effect application performance, and also another part of that question, you've mentioned CIFS as an example. What is it and why should we care about it?

Ameet Dhillon - F5 Networks
Sure, so chatty applications are pretty much as the name implies. Chatty in this sense means that the applications have a lot of back and forth. In other words, in order to do something like send some chunk of data or maybe authenticate a user, there are many back-end force that are required. You could think of it is a kind of a handshaking. You have to send a packet, receive a reply, send another one receive a reply. You might have to do this 100 times for example, just to do -- just to send a small amount of data. And so clearly you can see as latency grows, in other words as it takes longer for these round trips to happen, it's going to take longer for that entire transaction to complete. So, if I can do something in one round trip, it might only take me 300 milliseconds to do it, but if I have to do it a 100 times, it's going to take me 100 times, 300 milliseconds to do that same thing. And so, unfortunately there are a fair number of different applications or maybe protocols, a better way to put it, out there that are chatty. Probably the most prominent example is CIFS, spelled C-I-F-S and those are not familiar, actually stands for Common Internet File System. And the reason you should care about that is because CIFS, it's really a Remote File Access Protocol that forms the bases for Windows File Sharing.

So, if you've ever gone to a remote file share on Windows and I venture to say pretty much anybody who works on a computer in an enterprise has done this, must be actually trying to access a file share from Windows XP for example, that's not physically resent on your hard drive but it's actually in your network. Then you have used this as protocol, and if you've done that on a LAN, on a Local Area Network, you probably haven't experienced too many problems with it, it's little flakey in the LAN as well, but typically it works okay. The reason being is the bandwidth and the latency more importantly on a LAN is relatively small, it's on the border of a millisecond or even less. However, when latencies grow, meaning you're trying to access a file from your desk, we would say in San Francisco, and the file is actually resident in on a server sitting there in China, and you are trying to do that access, suddenly the performance of CIFS degrades considerably. So, I'll give you an example, so from a live test that we did. Taking a 30 megabyte file that you're downloading, you know let's say from China that 300 milliseconds latency over mostly at two megabytes/sec link. It would take about seven-and-a-half minutes to get that file, that 30 meg file.

Michael Johnson - PodTech
So, Ameet, what solutions does F5 offer to help with CIFS performance across a WAN?

Ameet Dhillon - F5 Networks
So, the main WAN Optimization solution that F5 provides is called WANJet, and it's actually that's an appliance-based solution and which is deployed symmetrically, by that we mean we take one appliance and deploy on one-end of the WAN Link and one on the other. So, for example if you had a WAN Link between United States and China you would deploy one WANJet on the US side and one WANJet on the Chinese side, and it's purpose of course is to optimize the application traffic flow across that WAN Link. And there are variety of different optimizations that WANJet can perform, a couple of the key ones are -- as mentioned earlier CIFS optimization essentially making while transfers more efficient. Just in general, mitigating the effects of the latency which can destroy application performance, certainly have a variety of different Data Reduction Techniques and even encryption for security purposes, encrypting traffic in between the two sides across the WAN, and typical performance improvements that customers see, clearly it will vary depending upon the type of WAN traffic you have, and the type of applications but certainly 5X to 10X is fairly typical and for how their repetitive data can go as high as 400-500X improvement.

Michael Johnson - PodTech
Is WAN Optimization only beneficial for low-speed links, like a T1 or less?

Ameet Dhillon - F5 Networks
No, absolutely not, it's certainly is beneficial for those kinds of links, but WAN Optimization in general is beneficial even for larger links and by larger links typically talking about something that's 45 megabytes/sec or higher, which is typically (Inaudible) was a T3, other common and sort of larger links are OC3 which is 155 megabytes or OC12 622 megabytes/second, and WANJet certainly works very, very well. In fact, much better than lot of the competition on these higher speed links.-Now, the obvious question might be is, so what kind of application is typical on, you know such large pipes, and the answer to that is typically Data Replication. So, particularly in this sort of Post-9/11 World that we live in with disaster recovery becoming a very common theme, there's a need to be able to replicate your databases to geographically dispersed areas.

So, for example, third typical example might be a financial company in Wall Street that has of course a lot of transaction data, maybe you remind backing records for example and they obviously can't afford to lose that and so and these are large, large volumes of data, you can imagine all the transactions that happen at a bank, and so for regulatory and just for good business practice reasons that they need to backup this data or replicate this data to a remote side and typically that remote side needs to be 150-200 or more miles away, so they might be in Florida for example. And so these are large volumes of information that have to be replicated on a very regular basis, and so as a result you typically need these really high, high pipes of 100 megabytes/second and above pipes. And even they're not good enough because of the problems that I described before in terms of latency and that sort of thing. And so putting a WANJet, between two of these, these storage systems helps considerably, in terms of the efficiency of backing up this large volume of data.

Michael Johnson - PodTech
What about compressing way in traffic? Will that help improve application performance?

Ameet Dhillon - F5 Networks
So, compressing WAN traffic it's certainly something that WANJet does very well, and -- but the answer to your question in general just compression of WAN, WAN traffic it can help, but it may not always, until -- let me explain what I mean by that. So, it certainly can help application performance to the extent that the problem that you're running into is your WAN Link, from your enterprise into a network is the one that's congested. So, it can certainly help there because the idea of compression of course is just to reduce the amount of data that's going across that physical link and so to the extent that you can reduce that amount of data that means other applications on the network have bandwidth available to transmit.

A typical example is Voice over IP. So, if you compress other traffic that's going across the link, and thereby -- provide more bandwidth then applications like Voice over IP may work better. Now, this of course assumes that your problem is just congestion of that WAN Link, and as I stated earlier that's often not the case, often the problem is beyond your control, so, it's things like latency, which is, not much you can do about it and from a physical perspective, it's just is related to distance or even the number of router hops in your network. And in that case you have to actually be careful because compression if not done appropriately could actually wind up adding more latency and it could even cause problems. So, a device like WANJet has to be very, very intelligent about how it does compression, and so, as an example you know WANJet's compression is very intelligent so, if it senses that the WAN Link that is attached to it is not very full, means there's not a lot of traffic link across it, it won't attempt to compress the traffic or if it detects that this is just uncompressible data, it's not going to foolishly try and compress it and waste time. So, again the short answer is, yes, compression can help with application performance, but if you're not careful it can also cause more problems than it solves, (Voice Overlap) application performance perspective.

Michael Johnson - PodTech
What about quality of service, is that helpful for application performance?

Ameet Dhillon - F5 Networks
A Quality of Service, this is an interesting one. So, everybody's got some opinion and thought on quality of service, and it means different things to different people. But, if you use the definition of Quality of Service meaning that you prioritize certain traffic over others. So, for example, you prioritize Voice over IP traffic over let's say, e-mail traffic. It certainly can help the Voice over of IP traffic because that's getting higher preference over the other traffic, but it could also hurt the traffic that's not high priority. So, in that sense, it may help one application but may harm another, and so one of the ways around this is of course to have other optimization techniques like I described earlier the TCP optimization or compression or CIFS acceleration, but also even for quality of service, you have to be very intelligent in how you use it. In other words, you don't want to just statically go in and reserve certain amount of bandwidth for a high priority application, even if that application is not using it. You got to be very intelligent about it and only reserve bandwidth when the application actually needs it. So, these are some of the things you have to sort of question your vendor on, in terms of how they're doing their quality of service.

Michael Johnson - PodTech
Can you tell me a little bit more about the F5 WANJet solution, and describe it a little bit?

Ameet Dhillon - F5 Networks
Sure, so WANJet is just an appliance-based solution that's offered by F5, it's actually a symmetric solution, and what we mean by that is you deploy one appliance on either end of your WAN link, so for example if you had a link between the US and China for example, you'd have one WANJet on the US side and one on the China side, and it's purpose in life is to optimize the traffic flow across those links, so the application flow across those links. Can applications be, you know Web applications or could be Siebel for your CRM or mail or what have your, you know just file sharing applications, and it provides a variety of different types of optimizations and different features which are applicable to some users and not others.

So, you can certainly selectively implement these, but, I think we've gone over most of them, but it offers CIFS optimization so to make sort of Microsoft Windows file sharing more efficient across a WAN, certainly offers QoS capabilities, and a variety of different data reduction or compression techniques which are more than sort of standard off-the-shelf compression techniques, some very advanced patented capabilities, and we actually refer to that particular capability as TDR (Transparent Data Reduction). In addition to that of course you can encrypt, you could selectively encrypt traffic going across the WAN so if it's very sensitive traffic, WANJet can actually encrypt it for your user's SSL Encryption. And you know typically it depends on the application, the application flows but certainly performance improvements of 3, 4, 5, 10X's is fairly common, and depending upon how repetitive your data, even upto 400-500 times improvement is possible, if you're sending the same data repeatedly.

Michael Johnson - PodTech
So, is there more information at the F5 Website, so that if one who's listening wants to find out a little bit more about the WANJet solution, they can go there to the Website.

Ameet Dhillon - F5 Networks
Absolutely, so our Website is www.f5.com, and specifically for optimization information, you can go to www.f5.com/products/optimization.html, and they'll provide you a plethora of information on -- not just the WANJet product but all of our other complementary offerings in F5.

Michael Johnson - PodTech
Okay, can you repeat that one more time the Website address.

Ameet Dhillon - F5 Networks
Sure, it's www.f5.com/products/optimization.html.

Michael Johnson - PodTech
I've been speaking today with F5 Networks' Ameet Dhillion, who's the Director of Product Management for Secure Remote Access and Wan Optimization Solutions. Ameet thanks for being with us on the Podcast.

Ameet Dhillon - F5 Networks
My pleasure Michael.

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