Abstract: A Fibre Channel Switch which enables end devices in different Fabrics to communicate with one another while retaining their unique Fibre Channel Domain_IDs. The Switch is coupled to a first fabric having a first set of end devices and a second fabric having a second set of end devices. The Switch is configured to enable communication by the first set of end devices associated with the first fabric with the second set of end devices associated with the second set of end devices using the unique Domain_IDs of each of the first set and the second set of end devices. In one embodiment of the invention, the first and second fabrics are first and second Virtual Storage Array Networks (VSANs) respectively. In an alternative embodiment, the first fabric and the second fabric are separate physical fabrics.

Abstract: An Fibre Channel Switch which enables end devices in different Fabrics to communicate with one another while retaining their unique Fibre Channel Domain_IDs. The Switch is coupled to a first fabric having a first set of end devices and a second fabric having a second set of end devices. The Switch is configured to enable communication by the first set of end devices associated with the first fabric with the second set of end devices associated with the second set of end devices using the unique Domain_IDs of each of the first set and the second set of end devices. In one embodiment of the invention, the first and second fabrics are first and second Virtual Storage Array Networks (VSANs) respectively. In an alternative embodiment, the first fabric and the second fabric are separate physical fabrics.

Abstract: Some embodiments of the present invention provide blade servers having blade switches that function as switches in the data plane, but do not have a Domain_ID. Control plane switching functions are performed by a fabric switch (e.g., a core switch) to which the blade server is attached. A fabric switch to which a blade switch is attached may perform address assignment functions for blades of the blade server. The blade switch preferably converts FLOGI requests to FDISC requests that are forwarded to an attached fabric switch. Some implementations provide for the multiple fabric switches, all of which are configured for communication with at least one blade switch, to establish and maintain the state of a virtual Domain_ID.

Abstract: In one embodiment, a solution is provided wherein redundant routers are treated as a single emulated switch. When a packet is received at a layer 2 edge switch from a host, the layer 2 edge switch may determine a switch identifier for the emulated switch using a destination anycast hardware address contained in the packet. The anycast hardware address may identify an emulated switch comprising a plurality of routers. Then a header may be added to the packet, the header including the switch identifier. Following that, the packet may be forwarded to another layer 2 switch along a shortest path from the layer 2 edge switch to the emulated switch.

Abstract: A solution is provided wherein the interfaces between multiple chassis (e.g., edge switches) in a network of layer 2 devices and a spanning tree device are treated as a single emulated switch. This emulated switch effectively enables two different views to the two different sides. Thus, frames from the network of layer 2 switches destined to any port of the emulated switch may take any of the links (through any of the physical switches), thereby enabling effective load-balancing for frames traveling from the layer 2 network side into the spanning tree device. Meanwhile the spanning tree device does not recognize an illegal loop in its connection to two different edge switches as it views the two links as a single logical EtherChannel.

Abstract: A metric measurement mechanism is used to determine network characteristics such as latency and round trip time with more precision than that available from layer three metric measurement mechanisms. The metric measurement mechanism can use the same architecture used by layer three metric measurement mechanisms while more accurately measuring network latency and isolating network device processing delays.

Abstract: A network node determines the suitability of coupled devices for being remotely line powered before actually powering them. The node scan its ports to determine which ports are coupled to devices. The node then interrogates the coupled devices. A unique discovery tone or bit pattern is generated and sent to devices coupled to ports. The node then monitors the port for a return signal. If there is a return signal, it is compared to the transmitted discovery signal. The signal will be identical after allowing for line losses if the coupled device is suitable for remote line powering. If the comparison yields a match, the network node supplies remote line power to the device.

Abstract: A network node determines the suitability of coupled devices for being remotely line powered before actually powering them. The node scan its ports to determine which ports are coupled to devices. The node then interrogates the coupled devices. A unique discovery tone or bit pattern is generated and sent to devices coupled to ports. The node then monitors the port for a return signal. If there is a return signal, it is compared to the transmitted discovery signal. The signal will be identical after allowing for line losses if the coupled device is suitable for remote line powering. If the comparison yields a match, the network node supplies remote line power to the device.

Abstract: A fibre channel frame is received at a first fibre channel switch. The fibre channel frame includes time stamp information associated with fibre channel switches between a second fibre channel switch and the first fibre channel switch. A time-to-live (TTL) value included in the fibre channel frame is determined. The fibre channel frame is sent back to the second fibre channel switch upon determining the TTL value included in the fibre channel frame.

Abstract: Disclosed are methods and apparatus for data tapping within a storage area network (SAN) and providing tapped data to a third party device, such as an appliance. In general, mechanisms are provided in a SAN to allow a data tap of data flowing between an initiator and a target. In one implementation, a data virtual target (DVT) in created in a network device to intercept data sent by a specific initiator to a specific logical unit of a specific target. The data or a copy of the data is sent to both the specific logical unit of the specific target and to an appliance. The data routing may be accomplished by use of a virtual initiator (VI), which is configured to send the data (or a copy of the data) to the specific target and the appliance. In a transparent mode of operations, the DVT has a same PWWN (port world wide name) and FCID (fibre channel identifier) as the specific target. In a first proxy mode of operation, the DVT has a different PWWN and FCID than the specific target.

Abstract: Some embodiments of the present invention provide blade servers having blade switches that function as switches in the data plane, but do not have a Domain_ID. Control plane switching functions are performed by a fabric switch (e.g., a core switch) to which the blade server is attached. A fabric switch to which a blade switch is attached may perform address assignment functions for blades of the blade server. The blade switch preferably converts FLOGI requests to FDISC requests that are forwarded to an attached fabric switch. Some implementations provide for the multiple fabric switches, all of which are configured for communication with at least one blade switch, to establish and maintain the state of a virtual Domain_ID.

Abstract: A technique is provided for implementing online restriping of a volume in a storage area network. A first instance of the volume is instantiated at a first port of the fibre channel fabric for enabling I/O operations to be performed at the volume. While restriping operations are being performed at the volume, the first port is able to concurrently perform I/O operations at the volume.

Abstract: Increased usage of network links is provided and smaller forwarding tables are required. A combination of STP and Multipath methods may be implemented in a network. Frames may be forwarded between switches not only according to MAC addresses, but also according to switch IDs and local IDs. Switch IDs do not need to be globally unique, but should be unique within a particular network. Local IDs need only be unique within a particular switch. Some preferred implementations allow frames to be delivered in order to devices requiring in-order delivery. Preferably, core switches need only learn the switch IDs of each core switch and each edge switch, and the appropriate exit port(s) corresponding to each switch. Preferably, the forwarding tables of each edge switch indicate the addresses of each device attached to that edge switch, the address of each device that is in communication with an attached device and the address of every other switch in the network.

Abstract: The present invention provides methods and devices for implementing a Low Latency Ethernet (“LLE”) solution, also referred to herein as a Data Center Ethernet (“DCE”) solution, which simplifies the connectivity of data centers and provides a high bandwidth, low latency network for carrying Ethernet and storage traffic. Some aspects of the invention involve transforming FC frames into a format suitable for transport on an Ethernet. Some preferred implementations of the invention implement multiple virtual lanes (“VLs”) in a single physical connection of a data center or similar network. Some VLs are “drop” VLs, with Ethernet-like behavior, and others are “no-drop” lanes with FC-like behavior. Some preferred implementations of the invention provide guaranteed bandwidth based on credits and VL. Active buffer management allows for both high reliability and low latency while using small frame buffers. Preferably, the rules for active buffer management are different for drop and no drop VLs.

Abstract: The present invention provides methods and devices for implementing a Low Latency Ethernet (“LLE”) solution, also referred to herein as a Data Center Ethernet (“DCE”) solution, which simplifies the connectivity of data centers and provides a high bandwidth, low latency network for carrying Ethernet and storage traffic. Some aspects of the invention involve transforming FC frames into a format suitable for transport on an Ethernet. Some preferred implementations of the invention implement multiple virtual lanes (“VLs”) in a single physical connection of a data center or similar network. Some VLs are “drop” VLs, with Ethernet-like behavior, and others are “no-drop” lanes with FC-like behavior. Some preferred implementations of the invention provide guaranteed bandwidth based on credits and VL. Active buffer management allows for both high reliability and low latency while using small frame buffers. Preferably, the rules for active buffer management are different for drop and no drop VLs.

Abstract: According to the present invention, methods and apparatus are provided to allow for distribution of fibre channel messages. Messages associated with a variety of applications can be distributed within a single logical fabric to physical connected but logically disconnected fabrics. Interconnecting switches forward messages to neighboring fabrics and aggregate responses before replying to a first fabric.

Abstract: A scalable NAS file system and protocols for implementing CIFS thereon are disclosed. In certain embodiments, the protocols implement the CIFS protocol on a scalable file server architecture having one or more protocol termination nodes, one or more file server nodes, and one or more disk controller nodes. Among the features that may be specifically implemented are tree access, file access, user authentication, locking, state maintenance, and failover of protocol termination nodes and file server nodes.

Abstract: A method and apparatus to improve the performance of a SCSI write over a high latency network. The apparatus includes a first Switch close to the initiator in a first SAN and a second Switch close to the target in a second SAN. In various embodiments, the two Switches are border switches connecting their respective SANs to a relatively high latency network between the two SANs. In addition, the initiator can be either directly connected or indirectly connected to the first Switch in the first SAN. The target can also be either directly or indirectly connected to the second Switch in the second SAN. During operation, the method includes the first Switch sending Transfer Ready (Xfr_rdy) frame(s) based on buffer availability to the initiating Host in response to a SCSI Write command from the Host directed to the target. The first and second Switches then coordinate with one another by sending Transfer Ready commands to each other independent of the target's knowledge.

Abstract: Methods and devices are provided for implementing security groups in an enterprise network. The security groups include first network nodes that are subject to rules governing communications between the first network nodes and second network nodes. An indicator, referred to as a security group tag (SGT), identifies members of a security group. In some embodiments, the SGT is provided in a field of a data packet reserved for layer 3 information or a field reserved for higher layers. However, in other embodiments, the SGT is provided in a field reserved for layer 1 or layer 2. In some embodiments, the SGT is not provided in a field used by interswitch links or other network fabric devices for the purpose of making forwarding decisions.

Abstract: Methods and apparatus are provided for determining characteristics associated with routes in fibre channel networks. Techniques are provided for inserting time stamp information into frames transmitted from a source to a destination and back to the source. Time stamp information allows a supervisor associated with a source to determine characteristics such as round trip times, latency between hops, and connectivity to a destination for specific routes.