can an access point connect through an access point?

[Neil Cherry]

Jeff Vian wrote:

> A PC (or other device) sends packets to an IP address.  The switch maps
> the IP to MAC to keep track of what is attached to each port and where
> to send traffic.  A TCP packet does not contain MAC addressing (although
> some protocols may).

This is partially incorrect, A PC does send to an IP address but the IP
address to MAC translation is done in the PC's TCP/IP stack. The IP
packet contains the MAC address which the PC must have before it can
send the TCP/IP packet anywhere. A layer 2 switch doesn't care about
an IP address (other than it's own for management). It's the ARP table
that has the translations for MAC to IP.

> ARP is a way for the local PC to see what is avialable, but if you check
> the ARP table on your PC it usually only remembers the MAC address for a
> very short time, thus the effect you describe above. 

See what's available is a bit ambigous but you are correct that the
arp entry last a _VERY_ short period of time.

> Also, remember, MAC addressing is only valid on the local LAN.  If it
> has to go through a router that cannot work.  Those protocols that do
> use MAC addressing are local LAN protocols only.

This is correct, a MAC address never traverses a router.

-- 
Linux Home Automation         Neil Cherry       ncherry at linuxha.com
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