which mac ???? plz help

Unanswered Question
Mar 20th, 2007
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suppose i have this diagram

R1 R2

O-------------------O----switch

| |

| |

Switch-- Pc1 pc2

10.0.0.1 20.0.0.1


Now if pc2 send packet to 10.0.0.1 ( routing is done) wat destination mac address will R1 uses when it sends the packet on its ethernet interface ??? will it arp for 10.0.0.1 and get pc1 mac address ?? or it will simply put broadcast mac address ?? i m confused plz tell me


thanks in advance


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ankbhasi Tue, 03/20/2007 - 01:56
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Hi Shaila,


It will arp for 10.0.0.1 and get pc 1 mac address and then will send the packet to pc1 directly using its mac address as destination mac address.


HTH


Ankur

sundar.palaniappan Tue, 03/20/2007 - 07:09
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Shaila,


Try to remember like this;


1. If a host needs to send a packet to a destination that's on the same subnet then it would ARP for the destination host address and get the MAC. The destination MAC in the ethernet frame would be that of the destination itself.


2. Instead, if the host wants packet to a host on a different subnet/network then it would ARP for the default gateway's MAC address. The destination MAC in the ethernet frame would be that of the gateway (router) itself. The router would then forward the traffic from thereon.


BTW, as you may know, ARP itself is a broadcast. Every host sees the broadcast but only the concerned host responds to the ARP request.


HTH


Sundar

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