Re: why is it taking so long to change interfaces?

From: Christopher Friesen (cfriesen@nortelnetworks.com)
Date: Mon Oct 16 2000 - 08:27:54 EST


Horst von Brand wrote:
>
> "Christopher Friesen" <cfriesen@nortelnetworks.com> said:
> > I'm trying to figure out why swapping from one NIC to another is taking
> > so long (on the order of a few seconds), and I was hoping one of you
> > could help me out.
>
> Remote machines cache the IP <--> MAC association...

Yes, that's why the "send_arp" step is in there--it sends out a
gratuitous arp reply that causes the other machines to update their arp
caches.

Anyways, as I said in the earlier message the delays that I am seeing
are on the outgoing side, not the incoming side. Incoming packets come
in on the new interface immediately (showing that the arp caches have
indeed been updated) but outgoing packets go out the old interface for
an additional few seconds after route shows the new interface as the
only way to access the .0.0 subnet.

-- 
Chris Friesen                    | MailStop: 043/33/F10  
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com
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