Analyzing the cost of Layer 7 Packet Shaping


November, 2010

By Eli RIles

For most IT administrators layer 7 packet shaping involves two actions.

Action 1:  Involves inspecting and analyzing data to determine what types of traffic are on your network.

Action 2: Involves taking action by adjusting application  flows on your network .

Without  the layer 7 visibility and actions,  an administrator’s job would degrade into a quagmire of random guesswork. Or would it?

Layer 7 monitoring and shaping is intuitively appealing , but it is a good idea to take a step back and break down examine the full life cycle costs of your methodology .

In an ironic inverse correlation, we assert that costs increase with the complexity of the monitoring tool.

1) Obviously, the more detailed the reporting tool (layer 7 ) , the more expensive its initial price tag.

2)  The kicker comes with part two. The more expensive the tool, the more  detail  it will provide, and the more time an administrator is likely to spend adjusting and mucking, looking for optimal performance.

But, is it a fair to assume higher labor costs with  more advanced monitoring and information?

Well, obviously it would not make sense to pay more for an advanced tool if there was no intention of doing anything with the detailed information it provides. Why have the reporting tool in the first place if the only output was to stare at reports and do nothing? Typically, the more information an admin has about a network, the more inclined he might be to spend time making adjustments.

On a similar note, an oversight often made with labor costs is the belief  that when  the work needed to adjust the network comes to fruition, the associated adjustments can remain statically in place. However, in reality, network traffic changes constantly, and thus the tuning so meticulously performed on Monday may be obsolete by Friday.

Does this mean that the overall productivity of using a bandwidth tool is a loss? Not at all. Bandwidth monitoring and network mucking can certainly result in a cost-effective solution. But, where is the tipping point? When does a monitoring solution create more costs than it saves?

A review of recent history reveals that technologies with a path similar to bandwidth monitoring have become commodities and shunned the overhead of most human intervention.  For example, computer operators disappeared off the face of the earth with the invention of cheaper computing in the late 1980′s.  The function of a computer operator did not disappear completely, it just got automated and rolled into the computer itself. The point is, anytime the cost of a resource is falling, the attention and costs used to manage it should be revisited.

An effective compromise with many of our customers is that they are stepping down from expensive complex reporting tools to a simpler approach. Instead of trying to determine every type of traffic on a network by type, time of day, etc., an admin can spot trouble by simply checking overall usage numbers once a week or so. With a basic bandwidth control solution in place (such as a NetEqualizer), the acute problems of a network locking up will go away, leaving what we would call only “chronic” problems, which may need to be addressed eventually, but do not require immediate action.

For example, with a simple reporting tool you can plot network usage by user.  Such a report, although limited in detail, will often reveal a very distinct bell curve of usage behavior. Most users will be near the mean, and then there are perhaps one or two percent of users that will be well above the mean. You don’t need a fancy tool to see what they are doing; abuse becomes obvious just looking at the usage (a simple report).

However, there is also the personal control factor, which often does not follow clear lines of ROI (return on investment).

What we have experienced when proposing a more hands-off model to network management is that a customer’s comfort depends on their bias for needing to know, which is an unquantifiable personal preference. Even in a world where bandwidth is free, it is still human nature to want to know specifically what bandwidth is being used for, with detailed information regarding the type of traffic. There is nothing wrong with this desire, but we wonder how strong it might be if the savings obtained from using simpler monitoring tools were converted into a trip to Hawaii.

In our next article, we’ll put some real world numbers to the test for actual break downs, so stay tuned. In the mean time, here are some other articles on bandwidth monitoring that we recommend. And, don’t forget to take our poll.

List of monitoring tools compiled by Stanford

Top five free monitoring tools

Planetmy
Linux Tips
How to set up a monitor for free

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