Modified filtering algorithm (MFA) for backbone interconnection-hardware design and implementation issues

The problem of fast filtering in bridging Ethernet local-area-networks (LANs) through high speed fiber distributed data interface (FDDI) networks is addressed. A filtering algorithm, called MFA is introduced, which sets the minimum power requirements for a bridge connecting an Ethernet LAN to an FDDI backbone. A hardware solution based on the use of content addressable memories is described. The MFA tries to avoid packet broadcasting on the FDDI ring. This is done by keeping track of remote Ethernet addresses coupled with the FDDI address of the related bridge. With MFA, the bridge performs filtering and routing operations only on packets coming from the Ethernet side, while the filtering from FDDI side is directly performed by the FDDI media access control. As a result, MFA has only to cope with the maximum Ethernet transmission rate, slower by one order of magnitude, and thus requiring less processing power