Subj : Knock Knock
To   : Alejandro Pelaez
From : Lawrence Garvin
Date : Wed May 30 2001 01:56 pm

Alejandro wrote to Carol at 03:37 27 May:

 AP> Erm, this echo is alive?.

Most definitely, Alejandro!

 AP> Can you explain me what happend with the source and destination mac
 AP> address while a packet is being forwarding through routers?. What 
 AP> happend with the mac address when the packet go thorough an 
 AP> ethernet interface, to a hdlc interface?. HDLC frame don't have 6
 AP> byte mac address, so how the arp request are forwarded?. Or they
 AP> aren't forwarded?. Hmmmm

The MAC address is stripped from the source packet when it is converted from an 
Ethernet frame (or Token Ring frame) to whatever framing type is used to 
transport the packet between the routers -- Frame Relay, HDLC, ATM, etc.

If the router is linking two LAN segments, the outbound Ethernet frame contains 
the MAC address of the outbound Ethernet (or Token Ring) MAC address.

When the final router receives the packet and places it on the destination LAN, 
the Ethernet (or Token Ring) frame that is created by that router contains the 
MAC address of the Ethernet (or Token Ring) interface connecting the router to 
the LAN.


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 * Origin: lawrence@eforest.net | The Enchanted Forest (1:106/6018)

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