[lwip-users] Re: [lwip] RFC: ARP (timing) behaviour

[Martin . Glunz]

> 
> The current etharp.c will remove pending items (and their queued
> packets!!)
> only
> after 10 seconds. This stresses the queuing implementation and memory
> usage enormously.
> 
> I would suggest lowering this to 2 seconds; ARP traffic is supposed to
> be
> low-latency.
> I did not search recommended timeouts values yet. Is someone aware of
> BSD's
> timeout values.

I don't know them exactly, but I see Linux sending arp requests
about every 2 seconds (if no one replies). After 5 or so requests it
stops and discards the packets.

> spec. on gratuitous ARP. I'm implementing this as we speak. See the
> top
> portion of:
> 
> http://rfc-3220.rfc-list.net/rfc-3220-69.htm
> 

Updating the ARP table upon receivement of any arp packet
is ok and a must. But I do not see a need to send sponteanously arp
updates, as our hw address usually never changes.

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