Riverbed Steelhead 1020 WAN Accelerator

WAN connectivity has always been a concern for every enterprise. The

bandwidth in India is not too costly today but it's not that cheap yet either.

The availability of high speed bandwidth in India is still limited and is mostly

restricted to Class A and B cities. Being a vast country geographically,

whenever we talk about multi-city connectivity, the latency due to the distance

becomes a major concern. We might keep spending money and upgrading bandwidth,

but we generally tend to forget that we cannot reduce the distance between the

two disparate locations and hence cannot reduce the latency between them.

Our experience suggests that if you double the link speed and at the same

time increase the latency to five times, then the actual data transfer speed

remains near about the same. So, there are two critical factors responsible for

a slow WAN: bandwidth (if it's not enough for the requirement) and latency. This

WAN accelerator is capable of managing both. It uses different technologies,

such as Application/protocol independent Caching, Protocol optimization (to

reduce the chattiness of applications to combat latency), Compression, WAFS

(Wide Area File system), and Web Application Acceleration to enhance data access

over WAN.

We received two boxes of the Riverbed SteelHead 1020 WAN accelerator for

review. They were essentially standard 1U rack mountable servers running dual

Xeon processors. Configuring them was not difficult. You can directly connect a

monitor and a keyboard to these boxes and boot into Steelhead's OS, which drops

you into a shell with a set of configuration commands; this pretty much

resembles the CISCO router interface. From this interface you can configure the

IP addresses of the box's WAN and primary interface. And once you do that you

can use the Primary port's IP address to connect the web based interface of the

device for configuration and for monitoring the box graphically. As the name

suggests, the WAN port is used to terminate the WAN link to the box. You would

also find a port called the 'LAN' just next to the WAN port. This port doesn't

require any additional IP address and again as the name suggests, is used to

connect the LAN to this device.

Test Results



To test this device thoroughly, we connected both WAN ports of the device to

each other through a WAN emulator and kept the subnet of both WANs as the same.

We configured the WAN emulator to emulate a network with 256Kbps of bandwidth

and 100 ms of latency. We then connected one of the WAN accelerator's LAN port

to our test network which had a couple of servers (Web, CIFS, FTP, etc). We then

connected the LAN port of the other box to a standard Core 2 Duo machine with

Windows XP SP2. One good feature of the device is that even if it completely

fails (due to power or hardware failure) it still doesn't disrupt WAN

connectivity; the data still passes through the device but of course

un-accelerated.

Once the setup was done, we first tried copying some data from the CIFS

server to the XP client. We first tried copying a 10MB folder with different

types of files, mostly zipped, so the scope of compressing it was negligible. It

took around 420 seconds to copy the entire data. Then we tried to copy the same

file again and the process happened in less than 5 seconds. The devices use

caching techniques to reduce the time taken for copying a file.

We then checked the time taken for the same 10 MB file to get copied without

the WAN accelerators in place. We removed both the accelerators from the network

and repeated the copying process again. This time the file took around 702

seconds to copy which is around 1.7 times more. This shows that, the device can

easily increase the speed to near about double even the first time data is

copied, which is commendable as the folder already contained zipped files that

could not be compressed any further.

Next, we decided to check how well this device works with text docs. We

created a single 4 MB text file and copied it without the accelerator. The file

took 229 seconds to get copied. Then we placed the WAN accelerators back in the

path and did the test again; this time it just took 17 seconds. Which is around

13.5 times faster. We copied it again through the accelerator and this time it

just took a second to copy.

Then we created a single 10MB text file with the same line written 1000 times

and tried copying with and without the accelerators in place. This time the

device easily detected that the file is highly compressible (as it had the same

text lines repeated) and it copied the complete 10MB file in 2.5 seconds, which

without the accelerators took somewhere around 700 seconds to get copied.

Then we tried modifying some part of the files which was once copied, or

renaming or changing their location. The device was smart enough to understand

each time that this is the same file and copied only the modifications instead

of copying the full file again and again and completed the copying process in a

few seconds. We even tried copying the same file through different protocols

(such as HTTP and FTP), but in this case also the device identified the files as

being copied earlier and just copied the modifications wherever necessary.

BOTTOM LINE : Overall the device gave us around 80% compression in all

protocols tested and gave marvelous results. So, if you are being bogged down

with poor speeds across your WAN links, then give this product a try.