The process shown in the figure is as follows:
|
1. |
R1 sends an ARP broadcast looking for 199.1.1.2's MAC
address. The switch floods the broadcast frame, so R2 and all other devices on
that LAN get the ARP broadcast.
|
|
2. |
R2 replies telling R1 that its MAC address is
0200.4444.4444.
|
|
3. |
R1 finishes creating the Ethernet header and trailer, with
R2's MAC address of 0200.4444.4444 as the destination, and forwards the frame. |
By the way, R1 keeps an ARP cache as well, so it knows that
199.1.1.2's MAC address is 0200.4444.4444. The next time R1 needs to forward a
packet to R2, R1 will not have to ARP.
Also, notice that this new Ethernet frame is not the same frame
that Hannah created and sent; the new Ethernet frame has a new source and
destination addresses. However, the IP packet inside the frame is mostly
unchanged. Because the IP packet is the entity that makes it through the network
without being changed, many people say that routers and routing forward packets
end to end through a network. That's because the word "packet" refers to the IP
header and data and does not include the data link header and trailer.
Sections
Comments (0 posted)
Syndication
