Re: Calculating bandwidth
Quote:
Originally Posted by
nigelhoath
Can I simply multiply and total up based on message pairs or do I have to take into account that a message pair with many packets will have a noticeable delay?
I suggest you to compare the results with a 3rd party bandwidth monitor.
(You can download a free utility here: http://www.dumeter.com/)
Personally I would capture all incoming and outgoing packets, and calculate the consumed bandwidth as required. (Per port, app, IP address, adapter, and so on).
The bandwidth calculation algorithm becomes trivial when you intercept the traffic.
You can implement your own library using LSP, NDIS, etc... Or you can use an existing library like Winpcap if you are looking for a quick result (http://www.winpcap.org/)
Good luck
Doron Moraz
Re: Calculating bandwidth
Doron tx for your reply. I now have some figures from a load test and these relate well to the figures I gleened from the network transaction traces (as of course they obviously would). But now my problem is building an algorithm to predict bandwidth requirement and service times when: a) the traffic increases and b) the user centre is restricted on bandwidth (usually for political reasons). I'm looking at round trip times greater than 300 ms.
One of my concerns is that as queues form service is likely to deteriorate exponentially. This may be a bigger problem where message pairs consist of many packets (?). Thus an algorithm based on a simple linear model will give a false confidense.
Obviously only a load test can give the true picture but if I can find an algorithm that gives reasonable predictions, allowing for high percentage usage, with a plus or minus factor that would greatly help reduce the costs of the decision making process. All the algorithms I have found appear to be based on a linear model. My gut feeling however is that the problem, if the results are to be accurate, is more complex than that.
Re: Calculating bandwidth
There are quite a few QOS algorithms with bandwidth prediction or LSTP that may help you to achieve your goal.
There is a very good article that you may find interesting:
http://web.njit.edu/~ansari/papers/05JON_Luo.pdf
It uses the least-mean square (LMS) algorithm for the prediction and it also cover the success probability.
Regards
Doron