D-Link DGS-3700 Series User Manual page 272

DGS-3700-12/DGS-3700-12G Series Layer 2 Gigabit Ethernet Switch User Manual
When PC B replies to the ARP request, its MAC address will be written into "Target H/W Address" in the ARP payload
shown in Table-3. The ARP reply will be then encapsulated into the Ethernet frame again and sent back to the sender.
The ARP reply is in a form of Unicast communication.
H/W Protocol H/W
type type address
length
Table – 3 (ARP Payload)
When PC B replies the query, the "Destination Address" in the Ethernet frame will be changed to PC A's MAC
address. The "Source Address" will be changed to PC B's MAC address (see Table-4).
Destination address
00-20-5C-01-11-11
Table – 4 (Ethernet frame format)
The switch will also examine the "Source Address" of the Ethernet frame and find that the address is not in the
Forwarding Table. The switch will learn PC B's MAC and update its Forwarding Table.
Forwarding Table
Port1 00-20-5C-01-11-11
Port2 00-20-5C-01-22-22
Protocol Operation
address
length
ARP reply
Source address Ether-type
00-20-5C-01-22-22
Sender Sender
protocol
H/W address
address
00-20-5C-01-11-11 10.10.10.1
ARP
261
Target Target
protocol
H/W address
address
00-20-5C-01-22-22 10.10.10.2
FCS