Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Is it possible to query the current size (or some kind of graph of the buffer-size over time for that matter) of the TCP buffer of a connection?

Each endpoint of a TCP connection will have a buffer for storing data that is transmitted over the network before the application is ready to read the data. source

share|improve this question
up vote 4 down vote accepted

The window size in the TCP header reflects the size of the remaining buffer on each end. You can graph this using Wireshark to both capture and analyze traffic (This isn't real time, but is usually how this sort of thing is done). Choose Custom IO Graph under Statistics and do something like the following (You need to choose Advanced for the Y-Axis):

enter image description here

The above graphs the window size for all packets where the source address in the packet is

share|improve this answer
If you think it is filling up you can also use tcp.analysis.zero_window – Kyle Brandt Mar 26 '12 at 21:22

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.