How to tune TCP/IP setting on i.MX6UL

[TammyTsai]

Hi NXP team,

I want to manage TCP sessions to comply with the following requirements.

1. The i.MX6UL custom board keeps track of all connections and restricts the number of sessions that can remain active on the device to the minimum necessary number.
2. The i.MX6UL custom board sets time limits for sessions and ensures that sessions are not left open for longer than necessary.

How to configure TCP/IP settings?

[TammyTsai]

Could anyone help me with this issue? 

[Harvey021]

Hi @TammyTsai 

Hope this can help for you - linux-imx/Documentation/networking/ip-sysctl.rst at lf-6.1.y · nxp-imx/linux-imx · GitHub

Regards

Harvey

[TammyTsai]

Hi @Harvey021 ,

I assume that the i.MX6UL custom board establishes no more than four connections, the idle connection would be closed after 90 seconds.

So, I try to modify two TCP variables below.

tcp_fin_timeout

path: kernel-source/include/net/tcp.h

change TCP_TIMEWAIT_LEN  from (60*HZ) to (90*HZ)

tcp_max_orphans

path: kernel-source/net/ipv4/tcp.c

change sysctl_tcp_max_orphans from (cnt/2) to 4

However, the i.MX6UL custom board can still connect to more than four servers.

Which variables should be modified?

How to change the value to comply with the requirements?

Best Regards,

Tammy