METHOD AND A SYSTEM FOR DYNAMICALLY UPDATING ARP CACHE TABLE OVER AD-HOC NETWORK, PARTICULARLY FOR DYNAMICALLY UPDATING INFORMATION REGISTERED IN AN ARP CACHE TABLE OF A DIFFERENT TERMINAL WHEN A PROTOCOL ADDRESS OF A TERMINAL EXISTING OVER AN AD-HOC NETWORK IS CHANGED DUE TO A COLLISION OF PROTOCOL ADDRESSES

摘要

PURPOSE: A method and system for dynamically updating an ARP(Auto Resolution Protocol) cache table over an ad-hoc network are provided to stably operate a communication environment with a high packet loss by dynamically correcting an error generated due to inconsistency of ARP cache tables. CONSTITUTION: When an IP address is detected to be repeated(S610), it is checked that whether each terminal having the repeated IP address is a terminal whose IP address has been changed or not(S620). If a terminal whose IP address value has been changed receives a packet from a neighbor terminal, the terminal checks whether an IP address of the received packet is the same as its IP address(S630). If they are different, the terminal transmits the packet to a terminal having the same IP(S640). The terminal whose IP address has been changed writes its MAC address in a source hardware address field of a selective ARP packet, an IP address used before the IP has been changed in a source protocol address field, no value in a destination hardware address field, and a broadcast address in a destination protocol address(S650). The terminal whose IP address has been changed broadcasts the selective UnARP packet with its fields filled(S660). When neighbor terminals receive the selective UnARP packet, they search an entry having the same IP as written in the source protocol address field of the selective UnARP from their own ARP cache table entry and check whether an MAC address of the entry is the same as a value of the source hardware address field of the selective UnARP(S670). If they are the same, the neighbor terminals delete the entry and add the entry having the correct IP address and MAC address value of the terminal which has transmitted the selective UnARP packet to the ARP cache table(S680).