Methods and apparatus for switching Fiber Channel Arbitrated Loop Systems
is provided between a plurality of Fiber Channel Loop devices. In one
aspect of the invention, the system switches based at least in part on
arbitrated loop primitives. An exemplary interconnect system may include
a first port and a second port, both including port logic to monitor
certain arbitrated loop primitives, a connectivity apparatus, a route
determination apparatus including a routing table consisting of ALPA
addresses and their associated ports, the route determination apparatus
coupled to each port and the connectivity apparatus, where the
connectivity apparatus creates paths between the ports based on
arbitrated loop primitives. In one embodiment, the connectivity apparatus
is a crossbar switch. Examples of the arbitrated loop primitives that
cause the switch to create paths between ports includes one or more of
the following: ARB, OPN and CLS. In yet other aspects, the system ensures
device access fairness through one or more techniques, including a
rotating priority system, a counter to count the number of OPNs,
especially sequential OPNs, and/or priority based on port type. Device
zoning may be implemented. In one implementation, the system includes
trunking such that frames may be transferred on multiple ports.