bdp bandwidth delay product how does server know its bandwidth?
All,
After lots of packet captures I have found the my slow throughput issue is due to a small window size. The scale is only at 4.
I know that the Window size scaling factor comes form the host using BDP (bandwidth X latency)
How does the host know its bandwidth? Does it use it nic card settings?
Comments
What makes you conclude that small window sizes are the problem?
When you say:
do you mean the Window Scaling shift factor, or the resulting multiplier?
A multiplier of 4 (which results from a shift factor of 2), allows the host to advertise a window size of up to 262,140 bytes. A shift factor of 4 results in a multiplier of 16 and allows the host to advertise a window size of up to 1,048,560 bytes.
The Window Scaling factor limits the maximum window size that a host can advertise, but does not determine the actual window size that it uses. It's useful to know the scaling factor, but only in order to calculate what window sizes the host is actually advertising. In order to correctly calculate the actual window sizes, the capture has to include the TCP three-way handshake ... (more)
Yes he knows his own bandwitdth by reading the NIC card setting. This setting is either negotiated or manually set. And the host does not know anythging about some bottlenecks on the path.