Forum

Hello All,

I was wondering if someone could recommend a good book on Packet Capture Analysis for wireless networks. I know some things about reading the packets but I would like to know more about the patterns and what to ralate it too. In the meantime, could someone help me with an issue I'm having.This is my problem. I have a data capture from a machine that is experiecning slow network(pages loading slowly). When I captured the packets coming from the laptop, I see a lot of CTS packets in a row. The laptop works fines in the hallway (approx 15 ft from desk). It kind of seems that there is something in the enviroment that is causing the laptop to backoff and try agian and agian.

Thanks,

Simpson,

http://www.cwnp.com/cwap/book/index.html

Its online only, but its free and really good.

Hopefully it'll make a comeback to print in the future.

Thanks for the link!! Do you know anything about this type of issue? What do you think about the continuous CTS Packets?

Thanks,

simpson Escribi?3:

Hello All,

I was wondering if someone could recommend a good book on Packet Capture Analysis for wireless networks. I know some things about reading the packets but I would like to know more about the patterns and what to ralate it too. In the meantime, could someone help me with an issue I'm having.This is my problem. I have a data capture from a machine that is experiecning slow network(pages loading slowly). When I captured the packets coming from the laptop, I see a lot of CTS packets in a row. The laptop works fines in the hallway (approx 15 ft from desk). It kind of seems that there is something in the enviroment that is causing the laptop to backoff and try agian and agian.

Thanks,

Are you using Meru? If you want to send me the capture and can see if I can figure something out.

GT

The flow of CTS frames you're seeing could be part of the protection mechanisms, but I'm not sure without looking at the packet capture.

GTHill Escribi?3:

simpson Escribi?3:

Hello All,

I was wondering if someone could recommend a good book on Packet Capture Analysis for wireless networks. I know some things about reading the packets but I would like to know more about the patterns and what to ralate it too. In the meantime, could someone help me with an issue I'm having.This is my problem. I have a data capture from a machine that is experiecning slow network(pages loading slowly). When I captured the packets coming from the laptop, I see a lot of CTS packets in a row. The laptop works fines in the hallway (approx 15 ft from desk). It kind of seems that there is something in the enviroment that is causing the laptop to backoff and try agian and agian.

Thanks,

Are you using Meru? If you want to send me the capture and can see if I can figure something out.

GT

No. I currently have Trapeze. I looked in my files and apparently I didn't save it as a capture. I thought I did. Anyhow, it did save it in a .cvs format which will open it up in excel or similiar software.

JimGeier Escribi?3:

The flow of CTS frames you're seeing could be part of the protection mechanisms, but I'm not sure without looking at the packet capture.

Yea. I was thinking the same. I've just never seen it in a capture. The AP is sending out the continuous CTS.

I didn't know if the continuous CTS from the AP was a sign that is cause of the slow thoughput for the user. As i mentioned, 15ft away from the desk in the hallway, throughput is better, much better. I'm going to go back to the site and get another capture with the laptop in the hallway. Maybe I can discover something between the two.

Thanks for the help and suggestions!!

Have you checked the RF environment is clear ?

You could be getting non 802.11 interference.

I would say you ALWAYS have to make sure your spectrum is clear before you troubleshoot higher up the stack.


NM

neilmac Escribi?3:

Have you checked the RF environment is clear ?

You could be getting non 802.11 interference.

I would say you ALWAYS have to make sure your spectrum is clear before you troubleshoot higher up the stack.


NM

You know, you're absolutely right! This location is in a residence hall. So anything from microwave - plumbing could be causing this. I wish i could check the spectrum but we do not have a spectrum analzyer. I'm tring to get one. Hopefully it will be soon. There is one thing... the student said it worked fine in the past but now it's becoming an issue. I know anything can change in a wireless environment.

Any amount of RF interference won't cause CTS frames. It could be an interference problem causing the slow speeds, but if you are seeing a high number of CTS frames we need to address that as well.

GT