Methods and apparatus for switching fibre channel arbitrated loop systems
View Patent ↗Methods and apparatus for switching Fibre Channel Arbitrated Loop Systems is provided between a plurality of Fibre 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.
1. A Fibre Channel Arbitrated Loop interconnect system comprising:
a first port in a plurality of ports,
a second port in the plurality of ports,
said first and second ports including port logic to monitor Open (OPN) arbitrated loop primitives, and adapted to connect to devices supporting a Fibre Channel Arbitrated Loop protocol,
a crossbar switch coupled to the plurality of ports,
a route determination apparatus including a routing table comprised of Arbitrated Loop Physical Addresses (ALPAs) and their associated ports, the route determination apparatus separate from the plurality of ports and directly coupled to each of the plurality of ports and the crossbar switch through separate signaling paths, the route determination apparatus configured for routing based on primitives by programming the crossbar switch to establish direct paths between the first and second ports in the crossbar switch according to received OPN arbitrated loop primitives, the direct paths excluding all other ports,
wherein the crossbar switch is configured as a primitive switch that creates the direct paths between the first and second ports based on the OPN arbitrated loop primitives, and
wherein priority for each port is independent of the ALPAs.
2. A system for interconnecting Fibre Channel Arbitrated Loop devices comprising:
a first Arbitrated Loop containing one or more Fibre Channel arbitrated ioop devices,
a second Arbitrated Loop device,
a Fibre Channel Arbitrated Loop interconnect system, the interconnect system including:
a first port in a plurality of ports, the first port containing port logic coupled to the first Arbitrated Loop,
a second port in the plurality of ports, the second port containing port logic coupled to the second Arbitrated Loop,
the first and second ports adapted to connect to devices supporting a Fibre Channel Arbitrated Loop protocol,
route determination apparatus separate from the plurality of ports and directly coupled to each of the plurality of ports through separate signaling paths and configured for routing based on primitives by selecting a direct route between the first and second ports based on received Fibre Channel Arbitrated Loop primitives from the ports, the direct route excluding all other ports, and including a routing table containing Arbitrated Loop Physical Addresses (ALPAs) and their associated ports, and
a crossbar switch directly coupled to the first and second ports and to the route detennination apparatus through separate signaling paths, the crossbar switch configured as a primitive switch for switching frames between ports under control of the route determination apparatus,
wherein Fibre Channel frames are transferred between a device on the first Arbitrated Loop and the second Arbitrated Loop device, and
wherein priority for each port is independent of the ALPAs.
3. The interconnect system of claim 2 wherein the Arbitrated Loop primitives that cause the crossbar switch to create paths between ports includes one or more of the following: Arbitrate (ARB), Open (OPN) and Close (CLS).
4. The interconnect system of claim 2 including a Receiver Ready (R_RDY) counter to count R_RDY's sent by an originating Fibre Channel Arbitrated Loop device before the Open (OPN) response is received by the originating Fibre Channel Arbitrated Loop Device.
5. The interconnect system of claim 2 wherein the second Arbitrated Loop device is on the first port.
6. The interconnect system of claim 2 wherein the second Arbitrated Loop device is on the second port.