Neighbor Greeting Protocols

Protocols

Neighbor Greeting Protocols

Neighbor greeting protocols are used to find data link and network layer addresses of other devices on the same LAN -including adjacent routers. This information is exchanged by transmitting special packets or messages between stations attached to a LAN. Stations store any information collected in local storage called caches. When a station needs to transmit data packets to another station, it looks in its cache for the address of the destination and, if found, places the address information in the data packets and sends them on their way. Different protocols have different algorithms for handling the case in which the destination information is not in the cache. The cache is usually purged periodically to remove outdated information.

As mentioned previously, a specific neighbor greeting protocol is typically deployed in conjunction with a particular routing protocol. The netWorks application contains simulations of the End System - Intermediate System (ES-IS) neighbor greeting protocol specified in ISO document ISO/IEC 9542 and the Address Resolution Protocol (ARP) defined in RFC 826. These protocols are used in conjunction with the IS-IS and OSPF routing protocols, respectively. The following sections provide a brief overview of the ES-IS and ARP protocols. The protocol details can be found in [Perlman 1992].

ES-IS

ARP

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