10-18-2005 09:37 AM - edited 03-03-2019 10:45 AM
I need to drive up my latency between a link to test an applications behavior. I have multiple routers I could use (1x3825 & 3x2801). I could use traffic shaping, but that doesn't let me input a latency delay in ms between packets... Any other thoughts??? Is there a way to put in latency in a bridge-group?
10-19-2005 05:48 PM
As you say, traffic shaping is an option and imho would be your best bet here.
You could also alter the MTU of the links, which in turn would increase fragmentation and reduce efficency (thus increasing latency).
Unfortunatly these techniques will only give approximated behaviour and will not produce hard and fast data (e.g. it'll be hard to simulate propogation delay if using disimilar physical mediums). If you need that level of assurance then building a lab that is closely matches the production system may be required.
The trouble you'll face in general is that unless you use a packet generator tuned to simulate your production network, any test you do in isolation will be based on disimilar operating conditions. In which case the best you can hope for is an approximation of behaviour.
Depending on whether you're testing the application itself or its impact on the network you could use a network analysis system (e.g. Smartbits - http://www.spirentcom.com) to introduce a sending delay between packets or simulate general operating conditions.
Again, depending on your test objectives you could also write a TCL script to fluctuate the QoS parameters over time.
HTH,
Colin
11-16-2007 10:00 AM
its not really a cisco solution but ive used monowall to do just exactly this many times in the past
sometimes its a bit hard to get working on spare hardware you may have due to compatibilty but ive had sucess with running it in a vmware virtual environment
the bad news is that it wont shape things in a bridge setup.
hope that helps somewhat...
ps; on a side note... it sounds as though you have some traffic shaping experiance, i dont suppose you have any insights into a post i just made ?
11-16-2007 10:01 AM
oh. nevermind. i see your post was from 2005.. youre most likely long gone and not looking at this any longer ...
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