From: Conor Daly (conor.daly at domain met.ie)
Date: Mon 13 Aug 2001 - 14:35:37 IST
On Mon, Aug 13, 2001 at 02:21:46PM +0100 or thereabouts, Paul Jakma wrote:
> On Mon, 13 Aug 2001, Conor Daly wrote:
>
> > Even when handling only one IP link to receive X frames?
>
> on ethernet, yep. (and presumably same for IP on other multi-access
> networks).
>
> to talk to another node you need it's MAC.
>
> to find out what MAC you need to talk to node with IP addr <foo>, a
> protocol called ARP is used it goes like:
>
> "hey, whose got <IP:foo>? tell <IP:bar>"
> "hi, <IP:foo> is <MAC:mac>"
>
> and <IP:bar> remembers the <IP:foo> -> <MAC> mapping and uses that.
>
> however, nodes only remember that association for a small lenght of
> time, iirc 30 seconds. (if you remember for a long period of time,
> then thngs like nodes changing IP addresses will not work very well -
> eg DHCP environment). Hence, nodes need to regularly use ARP, as they
> forget previous ARP replies within 30 seconds (ok, maybe not 30 - but
> something in that order). eg on linux cat /proc/net/arp to look at the
> current state of the ARP cache.
So, can I tell the kernel on the x-terminal:
"LOOK! THERE'S ONLY ONE SERVER FOR YOU TO TALK TO!"
"Go get its MAC address at boot and REMEMBER IT!!! And stop annoying
everyone else by asking the same question OVER AND OVER AGAIN!"
That'd be nice eh?
Conor
-- Conor Daly Met Eireann, Glasnevin Hill, Dublin 9, Ireland Ph +353 1 8064276 Fax +353 1 8064275 ------------------------------------ 1:31pm up 4 days, 22:34, 13 users, load average: 0.00, 0.00, 0.00
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