wireshark shows a frame with 2574 Bytes,
tcpdump shows the same frame as 2574 Bytes
A very good post:
http://sandilands.info/sgordon/segmentation-offloading-with-wireshark-and-ethtool
and you are sure that the MTU is 1500 or lower (no jumbo frames), since you saw the MSS in the SYN and SYN/ACK, so both sides are certainly below 1500.
Apparently this is because of the NIC doing tcp segmentation offloading:
# ethtool -k eth0
Offload parameters for eth0:
rx-checksumming: on
tx-checksumming: on
scatter-gather: on
tcp-segmentation-offload: on
udp-fragmentation-offload: off
generic-segmentation-offload: on
generic-receive-offload: off
large-receive-offload: on
ethtool -K eth0 tso off
ethtool -K eth0 gso off
ethtool -K eth0 gso off
I turned off tcp first but the generic did prevail so I turned off gso and thought I saw only smaller packages but when enabling and disabling it again I did not see the small packets anymore, so maybe a restart is necessary.
Would be nice to see it working or not the 2nd time you disable it. But I won't restart the system.
Would be nice to see it working or not the 2nd time you disable it. But I won't restart the system.
2 comments:
There are different products nowadays that are offered to increase UDP offloading and make sure to achieve a faster data transfer that how most people would use it.
NIC with Full TCP Offload
Thanks...
Full kernel Bypass technology is used for optimizing network performances. It decodes the network packets and passes the data from kernel space to user space by copying it |TCP offload IP Core|
TCP Offload, Full Kernel Bypass
Thanks for sharing nice or decent information here..please keep continue updates...
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