D-Link xStack User Manual page 334

xStack
Figure 2
When the switch floods the frame of ARP request to the network, all PCs will receive and examine the frame but only PC B will
reply the query as the destination IP matched (see Figure 3).
Figure 3
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 an Ethernet frame again and sent back to the sender. The ARP reply is in a
form of Unicast communication.
Table 3. ARP Payload
H/W Protocol H/W
Type Type Address
Length
When PC B replies to 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).
Table 4. Ethernet Frame Format
Destination Address
00-20-5C-01-11-11
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.
®
DGS-3400 Series Layer 2 Gigabit Ethernet Managed Switch
Protocol Operation
Address
Length
ARP reply
Source Address
00-20-5C-01-22-22
Sender Sender
H/W Address Protocol
Address
00-20-5C-01-11-11 10.10.10.1
Ether-Type
323
Target
H/W Address Protocol
00-00-00-00-00-00 10.10.10.2
ARP FCS
Target
Address