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.

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 non-disruptive monitoring of network traffic through one or more ports of a Fibre Channel network device. Preferred embodiments of the invention are used in conjunction with the switched port analyzer (“SPAN”) and/or remote SPAN (“RSPAN”) features. SPAN mode operation allows traffic through any Fibre Channel interface of a network device to be replicated and delivered to a single port on the same network device. Ingress SPAN allows the monitoring of some or all packets that ingress a specified port or ports. Egress SPAN allows the monitoring of some or all packets that egress a specified port or ports. RSPAN allows the delivery of the replicated traffic to a port on a remote network device. Filtering may be applied, for example, to SPAN packets having selected virtual storage area network numbers.

Abstract: Methods and devices are provided for the efficient allocation and deletion of virtual output queues. According to some implementations, incoming packets are classified according to a queue in which the packet (or classification information for the packet) will be stored, e.g., according to a “Q” value. For example, a Q value may be a Q number defined as {Egress port number ?? Priority number?? Ingress port number}. Only a single physical queue is allocated for each classification. When a physical queue is empty, the physical queue is preferably de-allocated and added to a “free list” of available physical queues. Accordingly, the total number of allocated physical queues preferably does not exceed the total number of classified packets. Because the input buffering requirements of Fibre Channel (“FC”) and other protocols place limitations on the number of incoming packets, the dynamic allocation methods of the present invention result in a sparse allocation of physical queues.

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: 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 devices are provided for encapsulating FC frames from a network device as Ethernet frames. Preferably, the FC frames represent traffic for a plurality of ports of the network device. The encapsulated Ethernet frames may be input to a conventional network interface card of a personal computer (“PC”) or laptop. Therefore, encapsulating the FC frames allows an engineer to use software installed on a conventional PC to troubleshoot problems with a network using FC protocol. According to some aspects of the invention, FC frames may be truncated to various degrees, to allow smaller data frames to be output at an appropriate rate to the analyzing personal computer, laptop, etc.

Abstract: An apparatus and method for a scalable network attached storage system. The apparatus includes a scalable network attached storage system, the network attached storage system including one or more termination nodes, one or more file server nodes for maintaining file systems, one or more disk controller nodes for accessing storage disks respectively, and a switching fabric coupling the one or more termination node, file server nodes, and disk controller nodes. The one or more termination nodes, file server nodes and disk controller nodes can be scaled as needed to meet user demands.

Abstract: A fast, lightweight, reliable, packet-based protocol that operates independent of the type of networking protocol used by the underlying physical layer of the network is disclosed. More specifically, the packet based protocol operates independently of or is capable of encapsulating physical layer protocols such as but not limited to MAC, Ethernet, Ethernet II, HARD or IP. The protocol defines at least three different types of frames including Information frames, Supervisory frames, and Unnumbered frames. In various embodiments of the invention, the Information, Supervisory, and Unnumbered frames include DSAP and SSAP field with semantics which are sufficiently large to support the various physical layer protocols that may be used on the network. The Information frames, Supervisory frames, and Unnumbered frames also have the ability to support urgent data delivery and certain memory management functions.

Abstract: Methods and devices are provided for detecting whether peer ports interconnecting two network devices can perform a novel protocol called Exchange Peer Parameters (“EPP”). If the peer ports are so configured to perform EPP, EPP services are exchanged between the peer ports. In a first phase, information is exchanged about peer port configurations of interest. In a second phase, the results of the exchange of information are applied to hardware and/or software of the respective ports, as needed.

Abstract: Methods and apparatus are provided for credit-based flow control. Techniques allow a receiver to provide buffer characteristic information to a sender using a single extended receiver ready signal. Multiple credits can be allocated using a single extended receiver ready signal as well. Counters and registers are used to allow for the accidental loss of extended receiver ready signals while still maintaining an accurate reflection of the types and numbers of buffers available.

Abstract: An apparatus and method for preventing the disruption of Fibre Channel Fabrics caused by ReConfigure Fabric (RCF) messages is disclosed. The apparatus includes a storage area network and a plurality of Fibre Channel Switches arranged in a Fabric. Each of the plurality of Switches includes logic to selectively configure their Ports to either reject or accept RCF messages. When configured to reject RCF messages, the Switch Port that receives an RCF message will generate a reject message along with a reason code explanation “E_Port Isolated”, and then transition into an Isolated state. When the Switch that generated the RCF message receives the reject message, its Port also transition into the Isolated state. In accordance with the method of the present invention, either a Storage Service Provider or a client can access the Switches of the Fabric through either a command line interpreter or a management application.

Abstract: High availability for a fibre channel switch in a storage area network can be implemented using redundant supervisors. An active supervisor can identify high availability characteristics associated with a message and determine whether the message should be mirrored onto a redundant supervisor, logged, and/or made persistent. Messages can be logged in a pending transaction buffer and stored using persistent storage services. Mirroring can be performed using synchronization queues that allow messages to be passed asynchronously to a redundant supervisor while maintaining full synchronization between supervisors and causing little delay to operation of the active supervisor.

Abstract: Methods and apparatus for encapsulating a packet or frame for transmission in a storage area network are disclosed. A packet or frame compatible with a standard protocol employed in the storage area network is received or generated. The packet or frame is then encapsulated with a virtual storage area network identifier. The packet or frame may further be encapsulated with at least one of a TTL value, MPLS information, and a type of traffic to be carried by the packet or frame. For instance, the type of traffic to be carried by the packet or frame may include Ethernet, Fibre Channel, and Infiniband. Once encapsulated, the encapsulated packet or frame is sent over the storage area network. For instance, the encapsulated packet or frame may be generated as well as transmitted by a switch over an inter-switch link in the storage area network.

Abstract: Methods and apparatus are provided for controlling congestion in a network such as a fibre channel network. Techniques are provided for characterizing traffic flow at a congested network node. The congested network node can generate various instructions such as quench messages to control traffic flow towards the congested network node. The quench messages can optionally include information about the characteristics of the congestion. The instructions are distributed to other nodes in the network. The other network nodes can interpret the instructions and control traffic flow towards the congested node.