Methods and apparatus for implementing exchange management for virtualization of storage within a storage area network

A method of managing exchanges in a network device of a storage area network, the network device having a plurality of ports, comprising:

• (a) receiving one or more frames from an initiator in a first exchange initiated by the initiator, the first exchange being between the initiator and the network device, at least one of the frames pertaining to access of a virtual storage location of a virtual storage unit representing one or more physical storage locations on one or more physical storage units of the storage area network;
• (b) initiating one or more additional exchanges by sending one or more frames from the network device to one or more targets, the additional exchanges each being between the network device and one of the one or more targets and being initiated in response to the first exchange, each of the targets being one of the physical storage units;
• (c) updating exchange information for the first exchange and the additional exchanges;
• and
• (d) linking the exchange information for the first exchange to the exchange information for the additional exchanges;
• wherein the exchange information for the first exchange and the additional exchanges indicates whether the corresponding exchange is between the initiator and the network device or between the network device and one of the targets;
• wherein (a), (b), (c), and (d) are performed by logic dedicated to a single one of the plurality of ports of the network device.

A network device adapted for managing exchanges in a storage area network, comprising:

• a plurality of ports, each of the plurality of ports having a dedicated processor, wherein at least one of the plurality of ports is each configured for:
• (a) at least one of receiving one or more frames from an initiator in a first exchange and sending one or more frames to the initiator in the first exchange, the first exchange being initiated by the initiator and being between the initiator and the network device, at least one of the frames pertaining to access of a virtual storage location of a virtual storage unit representing one or more physical storage locations on one or more physical storage units of the storage area network;
• (b) at least one of sending one or more frames from the network device to a target in a second exchange and receiving one or more frames from the target in the second exchange, the second exchange being between the network device and the target and being initiated in response to the first exchange, the target being one of the physical storage units;
• (c) updating exchange information for the first exchange and the second exchange;
• and
• (d) linking the exchange information for the first exchange to the exchange information for the second exchange;
• wherein the exchange information for the first exchange and the second exchange indicates whether the corresponding exchange is between an initiator and the network device or between the network device and a target;
• wherein (a), (b), (c), and (d) are performed by the processor dedicated to the corresponding one of the plurality of ports of the network device.

A network device adapted for managing exchanges in a storage area network, the network device having a plurality of ports, comprising:

• (a) means for at least one of receiving one or more frames from an initiator in a first exchange and sending one or more frames to the initiator in the first exchange, the first exchange being initiated by the initiator and being between the initiator and the network device, at least one of the frames pertaining to access of a virtual storage location of a virtual storage unit representing one or more physical storage locations on one or more physical storage units of the storage area network;
• (b) means for at least one of sending one or more frames from the network device to a target in a second exchange and receiving one or more frames from the target in the second exchange, the second exchange being between the network device and the target and being initiated in response to the first exchange, the target being one of the physical storage units;
• (c) means for updating exchange information for the first exchange and the second exchange;
• and
• (d) means for linking the exchange information for the first exchange to the exchange information for the second exchange;
• wherein the exchange information for the first exchange and the additional exchanges indicates whether the corresponding exchange is between the initiator and the network device or between the network device and one of the targets;
• wherein (a), (b), (c), and (d) are performed by logic dedicated to a single one of the plurality of ports of the network device.

An apparatus, comprising:

• a plurality of ports, each of the plurality of ports having a processor, one or more of the plurality of ports each being adapted for:
• (a) at least one of receiving one or more frames from an initiator in a first exchange and sending one or more frames to the initiator in the first exchange, the first exchange being initiated by the initiator and being between the initiator and the network device, at least one of the frames pertaining to access of a virtual storage location of a virtual storage unit representing one or more physical storage locations on one or more physical storage units of the storage area network;
• (b) at least one of sending one or more frames from the network device to a target in a second exchange and receiving one or more frames from the target in the second exchange, the second exchange being between the network device and the target and being initiated in response to the first exchange, the target being one of the physical storage units;
• (c) updating exchange information for the first exchange and the second exchange;
• and
• (d) linking the exchange information for the first exchange to the exchange information for the second exchange;
• wherein the exchange information for the first exchange and the second exchange indicates whether the corresponding exchange is between an initiator and the network device or between the network device and a target.

A network device adapted for managing exchanges in a storage area network, comprising:

• (a) means for receiving one or more frames from an initiator in a first exchange initiated by the initiator, the first exchange being between the initiator and the network device, at least one of the frames pertaining to access of a virtual storage location of a virtual storage unit representing one or more physical storage locations on one or more physical storage units of the storage area network;
• (b) means for initiating one or more additional exchanges by sending one or more frames from the network device to one or more targets, the additional exchanges each being between the network device and one of the one or more targets and being initiated in response to the first exchange, each of the targets being one of the physical storage units;
• (c) means for updating exchange information for the first exchange and the additional exchanges;
• and
• (d) means for linking the exchange information for the first exchange to the exchange information for the additional exchanges;
• wherein the exchange information for the first exchange and the additional exchanges indicates whether the corresponding exchange is between the initiator and the network device or between the network device and one of the targets;
• wherein (a), (b), (c), and (d) are performed by logic dedicated to a single one of a plurality of ports of the network device.

A network device adapted for managing exchanges in a storage area network, comprising:

• a processor;
• and
• a memory, at least one of the processor or the memory being adapted for:
• (a) receiving one or more frames from an initiator in a first exchange initiated by the initiator, the first exchange being between the initiator and the network device, at least one of the frames pertaining to access of a virtual storage location of a virtual storage unit representing one or more physical storage locations on one or more physical storage units of the storage area network;
• (b) initiating one or more additional exchanges by sending one or more frames from the network device to one or more targets, the additional exchanges each being between the network device and one of the one or more targets and being initiated in response to the first exchange, each of the targets being one of the physical storage units;
• (c) updating exchange information for the first exchange and the additional exchanges;
• and
• (d) linking the exchange information for the first exchange to the exchange information for the additional exchanges;
• wherein the exchange information for the first exchange and the additional exchanges indicates whether the corresponding exchange is between the initiator and the network device or between the network device and one of the targets;
• wherein (a), (b), (c), and (d) are performed by logic dedicated to a single one of a plurality of ports of the network device.

An apparatus, comprising:

• a plurality of ports, each of the plurality of ports having a processor associated therewith, wherein one or more of the plurality of ports is each configured for:
• (a) receiving one or more frames from an initiator in a first exchange initiated by the initiator, the first exchange being between the initiator and the network device, at least one of the frames pertaining to access of a virtual storage location of a virtual storage unit representing one or more physical storage locations on one or more physical storage units of the storage area network;
• (b) initiating one or more additional exchanges by sending one or more frames from the network device to one or more targets, the additional exchanges each being between the network device and one of the one or more targets and being initiated in response to the first exchange, each of the targets being one of the physical storage units;
• (c) updating exchange information for the first exchange and the additional exchanges;
• and
• (d) linking the exchange information for the first exchange to the exchange information for the additional exchanges;
• wherein the exchange information for the first exchange and the additional exchanges indicates whether the corresponding exchange is between the initiator and the network device or between the network device and one of the targets.

A system, comprising:

• a plurality of network devices, each of the plurality of network devices having a plurality of ports, each of the plurality of ports having a processor associated therewith, wherein one or more of the plurality of ports of each of the plurality of network devices is each configured for:
• (a) receiving one or more frames from an initiator in a first exchange initiated by the initiator, the first exchange being between the initiator and the network device, at least one of the frames pertaining to access of a virtual storage location of a virtual storage unit representing one or more physical storage locations on one or more physical storage units of the storage area network;
• (b) initiating one or more additional exchanges by sending one or more frames from the network device to one or more targets, the additional exchanges each being between the network device and one of the one or more targets and being initiated in response to the first exchange, each of the targets being one of the physical storage units;
• (c) updating exchange information for the first exchange and the additional exchanges;
• and
• (d) linking the exchange information for the first exchange to the exchange information for the additional exchanges;
• wherein the exchange information for the first exchange and the additional exchanges indicates whether the corresponding exchange is between the initiator and the network device or between the network device and one of the targets.