Set a Proper TCP Window Size
The TCP window size is too small. As a result, a device fails to send or receive packets with the size exceeding the TCP window size and TCP connections may be interrupted.
Scenario
Services established based on TCP connections, such as BGP and LDP services, are deployed.
Configuration Requirements
The tcp window window-size command is run in the system view to configure the TCP window size as a reasonable value.
Misconfiguration Risks
Risk description:
The tcp window window-size command is run in the system view to configure the TCP window size. For example, tcp window 1 indicates that the TCP window size is 1K.
The size of sent and received TCP packets exceeds the TCP window size, such as 1K in the preceding example.
If the preceding conditions are met, TCP connections are interrupted, which may affect TCP service forwarding.
Identification method:
Run the display tcp status command in the user view to check the TCP connection status.
If TCP connections are normal, the command output displays information about the TCP connections.
<HUAWEI> display tcp status
TCPCB Tid/Soid Local Add:port Foreign Add:port VPNID State 7800b1ec 6 /1 0.0.0.0:21 0.0.0.0:0 23553 Listening 72094f08 144/4 0.0.0.0:22 0.0.0.0:0 23553 Listening 78000714 144/1 0.0.0.0:23 0.0.0.0:0 23553 Listening 7800a90c 175/3 0.0.0.0:179 1.1.1.1:0 0 Listening 7208f1d8 175/6 0.0.0.0:179 1.1.1.2:0 0 Listening 7374df44 175/327 2.2.2.2:54269 3.3.3.3:179 0 Syn_Sent12d26d68 144/6 192.168.131.166:23 192.168.224.3:57582 0 Established 15691498 144/29 192.168.131.166:23 192.168.224.3:61044 0 Established 7375240c 144/23 192.168.131.166:23 192.168.242.37:50132 0 Established 12d23a60 144/5 192.168.131.166:23 192.168.242.37:54566 0 Established 7374bbc4 144/30 192.168.131.166:23 192.168.250.23:8426 0 Established 7067cff4 175/10 192.168.131.166:179 192.168.242.37:54512 0 Established
If TCP connections are interrupted, the command output does not display information about the TCP connections.
<HUAWEI> display tcp status
TCPCB Tid/Soid Local Add:port Foreign Add:port VPNID State 7800b1ec 6 /1 0.0.0.0:21 0.0.0.0:0 23553 Listening 72094f08 144/4 0.0.0.0:22 0.0.0.0:0 23553 Listening 78000714 144/1 0.0.0.0:23 0.0.0.0:0 23553 Listening 7800a90c 175/3 0.0.0.0:179 1.1.1.1:0 0 Listening 7208f1d8 175/6 0.0.0.0:179 1.1.1.2:0 0 Listening 7374df44 175/327 2.2.2.2:54269 3.3.3.3:179 0 Syn_Sent
Recovery measures:
Configure the TCP window size as a reasonable value.
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