Dynamic inter-VSAN topology discovery

An apparatus adapted for discovering topology in a storage area network having a plurality of VSANs in a network fabric, wherein the VSANs include a first VSAN having a plurality of network devices, the apparatus being in the form of a first network device of the first VSAN and comprising:

• one or more processors;
• one or more memory, wherein at least one of the processors and memory are adapted for:
• (a) defining the first network device as a Topology Update (TU) Owner, wherein the other network devices of the first VSAN are not defined as TU Owners;
• (b) at the first network device, receiving data that indicates a topology change in the first VSAN and includes an identifier for a virtual switch of the first VSAN that corresponds to a device of another VSAN that has been propagated into the first VSAN, wherein such virtual switch has a same domain as the propagated device, which domain is unused by other switches corresponding to non-propagated devices of the first VSAN, wherein the topology change indicates one or more of the following:
• a network device has been added to the first VSAN, a network device has been removed from the first VSAN, or a plurality of network devices have been connected in a new configuration in the first VSAN;
• (c) at the first network device, generating or updating one or more TU database(s) for the plurality of VSANs of the network fabric based on the received topology change;
• and
• (d) the first network device causing the topology change to be propagated in the form of a Topology Update across the network fabric to network devices in the plurality of VSANs of such network fabric, wherein the Topology Update indicates that data in the Topology Update should be propagated by receiving network devices throughout the VSANs of the fabric.

An apparatus for discovering topology in a storage area network having a plurality of VSANs in a network fabric, wherein the VSANs include a first VSAN having a plurality of network devices, the apparatus being in the form of a first network device of the first VSAN and comprising:

• means for defining the first network device as a Topology Update (TU) Owner, wherein the other network devices of the first VSAN are not defined as TU Owners;
• means for receiving data that indicates a topology change in the first VSAN and includes an identifier for a virtual switch of the first VSAN that corresponds to a device of another VSAN that has been propagated into the first VSAN, wherein such virtual switch has a same domain as the propagated device, which domain is unused by other switches corresponding to non-propagated devices of the first VSAN, wherein the topology change indicates one or more of the following:
• a network device has been added to the first VSAN, a network device has been removed from the first VSAN, or a plurality of network devices have been connected in a new configuration in the first VSAN;
• means for generating or updating one or more TU database(s) for the plurality of VSANs of the network fabric based on the received topology change;
• and
• means for causing the topology change to be propagated in the form of a Topology Update across the network fabric to network devices in the plurality of VSANs of such network fabric, wherein the Topology Update indicates that data in the Topology Update should be propagated by receiving network devices throughout the VSANs of the fabric.

A network system for discovering topology in a storage area network, comprising:

• a plurality of VSANs, wherein each VSAN is coupled to at least one other VSAN and each VSAN has one or more associated hosts and storage devices;
• one or more intermediate switches that each belong to a single one of the VSANs;
• and
• one or more border network switches that each belong to two or more adjacent VSAN(s) wherein each adjacent pair of VSANs includes at least one border network device,
• wherein a first intermediate switch in each VSAN is defined as a Topology Update Owner and the other switches of each VSAN are not defined as Topology Update Owners, wherein each first intermediate switch of each VSAN is operable to:
• receive data that indicates a topology change in the each first intermediary switch's VSAN and includes an identifier for a virtual switch of the first VSAN that corresponds to a device of another VSAN that has been propagated into the first VSAN, wherein such virtual switch has a same domain as the propagated device, which domain is unused by other switches corresponding to non-propagated devices of the first VSAN, wherein the topology change indicates one or more of the following:
• a switch has been added to the first VSAN, a switch has been removed from the first VSAN, or a plurality of switches have been connected in a new configuration in the first VSAN;
• generate or update one or more TU database(s) for the plurality of VSANs of the network system based on the received topology change;
• and
• cause the topology change to be propagated in the form of a Topology Update across the network system to the intermediate and border switches in each of the plurality of VSANs of such network fabric, wherein the Topology Update indicates that data in the Topology Update should be propagated by receiving switches throughout the VSANs of the fabric.