图21.521.1，ARP请求与回答分组 A 130.23.43.20 130.23.43.25 B B234:55:1022:10 A4:6E:F4:59:83:AB ARP Request 0x0001 0x0800 0x060x04 0x0001 0xB23455102210 130.23.43.20 0x000000000000 130.23.43.25 ARP Reply 0x0001 0x0800 0x060x04 0x0002 0xA46EF45983AB 130.23.43.25 0xB23455102210 130.23.43.20 Time Time 21.1021.10 图 21.5 例21.1, ARP 请求与回答分组