US 6,192,054 B1 · Accelerated fibre channel hub and protocol

Abstract

An apparatus for accelerated Fiber Channel protocol handshaking and data exchange involves dividing a Fiber Channel arbitrated loop architecture up into a plurality of arbitrated subloops, each of which arbitrates locally using the same fundamentals as the Fiber Channel arbitration protocol but with some slight modifications which do not affect the compatibility of standard Fiber Channel nodes. Each subloop is coupled to a hub port which contains a state machine which implements distributed intelligence to do switching function and fill word generation to implement the accelerated protocol by using a plurality of switching, fill word generation and token passing rules. The state machine in each hub port is coupled to its local subloop and to its neighboring hub ports through a single TDMA bus which has timeslots dedicated to carrying broadcast loop and return loop traffic and control token traffic. In some embodiments, the hub ports are coupled to their neighboring hub ports by separate broadcast and return loops and a control loop used for token passing.

Claims12

Dependent claims

A Fibre Channel Arbitrated Loop network, comprising:

a plurality of subloops, each subloop coupling a plurality of Fibre Channel Arbitrated Loop nodes by a data transmission medium;
a plurality of hub port means, each hub port means having subloop data ports coupled to a subloop such that data can be transmitted into the subloop and received from said subloop, and each hub port means having broadcast data ports for coupling to a broadcast loop transmission medium and having return loop data ports for coupling to a return loop transmission medium, each said hub port means for establishing switching connections to accelerate data transmissions between source and destination Fibre Channel Arbitrated Loop nodes by causing the subloops upon which said source and destination nodes are resident, if they are resident on different subloops, to be coupled together such that data passing between said source and destination Fibre Channel Arbitrated Loop nodes does not have to pass through all the Fibre Channel Arbitrated Loop nodes on any subloop on which neither the source Fibre Channel Arbitrated Loop node nor destination Fibre Channel Arbitrated Loop node is resident;
a broadcast loop transmission medium coupling all said hub port means together via their said broadcast data ports;
and
a return loop transmission medium coupling all said hub port means together via their said return loop data ports;
and
a control loop coupling all said hub port means together to carry control token data.

4 more elements

A Fibre Channel Arbitrated Loop network, comprising:

a plurality of subloops, each comprised of:
a hub port means means for receiving inbound ARB primitives and substituting an ARB (F0) priority ranking into any received ARB primitive to generate a modified ARB primitive, and transmitting the modified ARB primitive out onto said subloop, each hub port means having an inbound data port and an outbound data port;
a transmission medium coupled to said inbound data port and said outbound data port of said hub port means;
a plurality of Fibre Channel Arbitrated Loop nodes, each having inbound and outbound data ports coupled to said transmission medium, each said Fibre Channel Arbitrated Loop node having a priority ranking and having arbitration means for examining the priority of inbound ARB primitives and substituting the priority ranking of said Fibre Channel Arbitrated Loop node in said ARB primitive if said Fibre Channel Arbitrated Loop node desires control of said Fibre Channel Arbitrated Loop network if and only if the priority ranking of the inbound ARB primitive is lower than the priority ranking of said Fibre Channel Arbitrated Loop node so as to generate a modified ARB primitive, and transmitting said modified ARB primitive out on said transmission medium, and, if the priority ranking of the inbound ARB primitive is higher than the priority ranking of the Fibre Channel Arbitrated Loop node, retransmitting the ARB primitive unchanged;
and further comprising a broadcast loop transmission medium and a return loop transmission medium coupling said each said hub port means together in a ring topology;
and wherein each said hub port means further comprises means for receiving an ARB token and stopping substituting priority ranking F0 into inbound ARB primitives and retransmitting said incoming ARB primitives unchanged;
and wherein said arbitrations means in each of said Fibre Channel Arbitrated Loop nodes includes means for examining incoming ARB primitive priority rankings, and if a match to said Fibre Channel Arbitrated Loop node's priority ranking is found, determining that said Fibre Channel Arbitrated Loop node is to be the source node in a Fibre Channel Arbitrated Loop Tenancy data transfer and transmitting an OPN primitive identifying a destination node to which data is to be sent during said loop tenancy;
and wherein each said hub port means further comprises means for examining each OPN primitive arriving at its inbound data port from the subloop to which said hub port means is connected and making a determination if the destination Fibre Channel Arbitrated Loop node identified in an OPN primitive is on the same local subloop to which said hub port means is connected, and, if so, making a switching connection such that data can pass between said source and destination Fibre Channel Arbitrated Loop nodes on the subloop transmission media to which said hub port means is connected without the need for said data to propagate across either said broadcast loop or said return loop, and, if the destination Fibre Channel Arbitrated Loop node identified in an OPN primitive arriving at said inbound data port from a source Fibre Channel Arbitrated Loop node on the subloop to which said hub port means is connected is not on the same said local subloop as said source Fibre Channel Arbitrated Loop node, broadcasting said OPN primitive on said broadcast loop to all other hub port means, and wherein each said hub port means includes means for receiving broadcast OPN primitives from said broadcast loop and transmitting said broadcast OPN primitives on their local subloops, and wherein each said hub port means includes means for making a determination as to which subloop has the destination Fibre Channel Arbitrated Loop node identified in said broadcast OPN primitive coupled thereto, said determination made by determining the primitives that arrive at predetermined ports of said hub port means and the order in which they arrive and drawing inferences therefrom according to predetermined rules, and making appropriate switching connections based upon said inferences such that only the subloops having the source and destination Fibre Channel Arbitrated Loop nodes coupled thereto are coupled together through said broadcast and return loop transmission media such that data flowing between said source and destination Fibre Channel Arbitrated Loop nodes does not need to flow through any Fibre Channel Arbitrated Loop nodes on subloops not having either the source or destination node coupled thereto.

5 more elements

Dependencies are inferred from the claim text.

Accelerated fibre channel hub and protocol

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Accelerated fibre channel hub and protocol

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Abstract

Claims12