Abstract: A translation engine for translating frames of data from one frame format to another frame format in the same manner as an IEEE 802.1D MAC layer transparent bridge as required when transferring frames of data between interconnected heterogeneous local area networks. The translation engine is comprised of a variable length data pipeline capable of maintaining a constant synchronous data stream comprising frames of data from the input to the output of the data pipeline, without introducing any gaps in the data stream caused by removing fields of a frame, or causing the data stream to halt by inserting fields of a frame during translation of a frame from one frame format to another frame format.

Abstract: Multicast and broadcast frames transmission rate logic limiting the rate at which multicast or broadcast frames are forwarded by a MAC layer device interconnecting local area networks such as a bridge or switching hub, so as to prevent multicast or broadcast storms from propagating from one local area network to another local area network. Such logic is distributed among a plurality of local area network (LAN) ports of a switching hub, allowing the overall maximum rate at which such frames may be transmitted to be individually tuned on a per LAN port basis. The transmission rate logic includes a burst capability, in which the overall rate to which multicast and broadcast frames may be limited can be exceeded for a finite number of such frames. The burst capability may also be individually tuned on a per LAN port basis.