D-Link DES-3828 Product Manual - Page 446

xStack DES-3800 Series Layer 3 Stackable Fast Ethernet Managed Switch CLI Manual When the switch receives the frame, it will check the "Source Address" in the Ethernet frame's header. If the address is not in its Forwarding Table, the switch will learn PC A's MAC and the associated port into its Forwarding Table. Forwarding Table Port1 00-20-5C-01-11-11 In addition, when the switch receives the broadcasted ARP request, it will flood the frame to all ports except the source port, port 1 (see Figure -2). Who is 10.10.10.2? C A 00-20-5C-01-33-33 10.10.10.3 Port 3 Port 4 D Port 1 Port 2 00-20-5C-01-11-11 10.10.10.1 B 00-20-5C-01-44-44 10.10.10.4 00-20-5C-01-22-22 10.10.10.2 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). C 00-20-5C-01-33-33 10.10.10.3 D 00-20-5C-01-44-44 10.10.10.4 Figure-3 Who is 10.10.10.2? A Sender Port 3 Port 4 Port 1 Port 2 00-20-5C-01-11-11 10.10.10.1 B Target I am 10.10.10.2 00-20-5C-01-22-22 10.10.10.2 When PC B replies 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 Ethernet frame again and sent back to the sender. The ARP reply is in a form of Unicast communication. 442