Fibre channel arbitrated loop bufferless switch circuitry to increase bandwidth without significant increase in cost
First Claim
1. A process for establishing one or more concurrent data transfers between different pairs of nodes comprising the steps:
- for each desired data transfer, sending to a switch from a source node a request to start a loop tenancy with a destination node, said request being in the form of a Fibre Channel Arbitrated Loop (hereafter FCAL) primitive and including a tag which identifies the destination node with which data is to be exchanged;
receiving said request and tag in a switching circuit coupled to the FCAL upon which said source node is resident and using said tag to determine from a table of nodes resident on said FCAL upon which said source node is resident if said destination node is resident thereon;
if said destination node is not resident on said FCAL upon which said source node is resident, using a control channel on a multiplexed bus having data transfer channels and control channels to circulate said request and tag to other switching circuits coupled each of said other FCALs;
in each said other switching circuit, using said tag to determine from a table of nodes resident on said FCAL to which said switching circuit is coupled if said destination node is resident on a local FCAL coupled to said switching circuit to facilitate data transfers between the source node and the destination node.
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Accused Products
Abstract
A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL network and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which causes both ports to establish a data path through the backplane crossbar switch.
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Citations
19 Claims
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1. A process for establishing one or more concurrent data transfers between different pairs of nodes comprising the steps:
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for each desired data transfer, sending to a switch from a source node a request to start a loop tenancy with a destination node, said request being in the form of a Fibre Channel Arbitrated Loop (hereafter FCAL) primitive and including a tag which identifies the destination node with which data is to be exchanged; receiving said request and tag in a switching circuit coupled to the FCAL upon which said source node is resident and using said tag to determine from a table of nodes resident on said FCAL upon which said source node is resident if said destination node is resident thereon; if said destination node is not resident on said FCAL upon which said source node is resident, using a control channel on a multiplexed bus having data transfer channels and control channels to circulate said request and tag to other switching circuits coupled each of said other FCALs; in each said other switching circuit, using said tag to determine from a table of nodes resident on said FCAL to which said switching circuit is coupled if said destination node is resident on a local FCAL coupled to said switching circuit to facilitate data transfers between the source node and the destination node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A process for establishing one or more concurrent data transfers between different pairs of nodes comprising the steps:
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for each desired data transfer, sending to a switch from a source node a request to start a loop tenancy with a destination node after arbitrating for and winning control of a FCAL upon which said source node is resident, said request being in the form of FCAL OPN primitive and including a tag which identifies the destination node with which data is to be exchanged; receiving said request and tag in a switching circuit coupled to the FCAL upon which said source node is resident and using said tag to determine from a table of nodes resident on said FCAL upon which said source node is resident if said destination node is also resident thereon; if said destination node is not resident on said FCAL upon which said source node is resident, using a control channel on a multiplexed bus having data transfer channels and control channels to broadcast a destination node location request and the destination address of the destination node identified in said OPN primitive, said request requesting other switching circuits coupled each of said other FCALs to search their tables to determine which of them is coupled to the FCAL to which the destination node is connected; in each said other switching circuit, using said destination address as a search key to search a table of addresses of nodes resident on said FCAL to which said other switching circuit is coupled to facilitate data transfers between the source node and the destination node. - View Dependent Claims (11, 12, 13, 14)
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15. A switch for selectively, concurrently coupling the nodes on a plurality of a Fibre Channel Arbitrated Loops together comprising:
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a multiplexed bus; a plurality of switch control means, each for coupling to one local FCAL network, and each coupled to said multiplexed bus, each for receiving OPN primitives from a source node on the local FCAL network to which said control means is coupled and determining if the destination node identified in said OPN corresponds to said local FCAL network by searching a table of destination addresses for nodes on the local FCAL of said switch control means to determine if the destination node is located on the local FCAL to which said switch control means is coupled, and, if so, routing the OPN to the destination node via a local traffic data path in said switch control means and the local FCAL network, but if the destination node is not on said local FCAL, transmitting a destination node location request and the destination address of the destination node identified in said OPN primitive to all said other switch control means via a channel on said multiplexed bus, and for scanning messages received back from said other switch control means to determine which switch control means and local FCAL network to which flow control primitives and data are to be transferred to accomplish the desired data transfer. - View Dependent Claims (16, 17, 18, 19)
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Specification