Hi,
I have observed that NH (nexthop) entry deletion (in linux stack) from FAILED state is 9-10 min. Can anybody let me know what is default value for this and how to change this. I can reproduce this scenario by sending the traffic to host which is not available. For the unavailable host stack try to resolve the ARP(NH) and move the entry into FAILED state. Now I check the time stack is taking to delete this NH entry. I am putting some of the /proc parameters value from my system.

/proc/sys/net/ipv4/neigh/default/gc_stale_time = 60
/proc/sys/net/ipv4/neigh/default/gc_interval = 30
/proc/sys/net/ipv4/neigh/testDev/gc_stale_time = 120 >> testDev is the L3 interface (netdevice) on which I am testing the case
/proc/sys/net/ipv4/neigh/testDev/base_reachable_time = 175
/proc/sys/net/ipv4/neigh/testDev/base_reachable_time_ms = 17500

Ramanand

The time to remove stale ARP entry is complicated. It is relative to /proc/sys/net/ipv4/route/gc_timeout, base_reachable_time, gc_stale_time and gc_interval. The big one could gc_timeout, normal is 5 minutes.

Thanks. I want to get the FAILED to Delete time around 1 sec. Can you suggest some values for these parameters to achieve this value.

The FAILED to delete time around 1 second isn't reasonable value. Why do you want this kind of fast deletion?

It's nice. Thanks a lot.

Hi Nini,
My application configure hardware on Delete notification. There I need this timing

If hardware configuration is changed and it trigger ARP flush, ARP API should be called to flush these ARP entry and shouldn't use timeout mechanics to clean up.

Requirement is not ARP flush. Scenario is slightly different. Its a complex application, where I need to trigger some operations in application and hardware when ARP is FAILED to resolved.

It has a hard way to do it, adding a hook in ARP code when ARP resolve is fail.

Ok, Well meanwhile I changed my application now. So whatever processing I was doing earlier on NH Delete notification, started doing that on FAILED notification also.
Thanks for your support.