Abstract: One embodiment of the present invention provides a system that facilitates automatic adjustment of logical channels in a Fibre Channel (FC) network. During operation, the system receives FC data frames. A respective data frame is associated with a logical channel. The bandwidth on an FC link can be allocated into a plurality of logical channels, and a respective logical channel is associated with a dedicated buffer and can transport a plurality of data flows with data frames of variable length. The system then identifies a slow data flow in a first logical channel. Next, the system assigns the slow data flow to a second logical channel, thereby preventing the slow data flow from slowing down other data flows in the first logical channel. The system subsequently forwards the data frames in the slow data flow on the second logical channel onto an outgoing link.

Abstract: A smoothing algorithm for round trip time (RTT) measurements is provided to a network device to effectively deal with variations or other potential anomalies that may occur in RTT measurements. The algorithm involves: first determining what should be considered a very high or a very small value for a RTT sample. If a new RTT sample is in an acceptable range, then the network device performs a relatively basic smoothing. If the new RTT sample is much higher than a current RTT value, then the network device ignores the value of this RTT sample a few times. If the network device still detects this large value after ignoring that value for some time, then the network device factors this value into the current RTT value using an additive increase. Similarly, if the value of the new RTT sample is much lower than current RTT value, the network device ignores the value of the new RTT sample a few times.

Abstract: An IP gateway device establishes distinct TCP sessions within a single FCIP tunnel, each TCP session being designated for a different priority of service (e.g., high, medium, low), plus a control stream. Each TCP session has its own TCP stack and its own settings for VLAN Tagging (IEEE 802.1Q), quality of service (IEEE 802.1P) and Differentiated Services Code Point (DSCP). By distributing data streams assigned to different priorities of service into different TCP sessions within the FCIP tunnel, an IP gateway device can preserve the distinctions between the data stream priorities while the data traffic is within the IP network.

Abstract: A switch may be used to force the expiration of a cookie on a user's system by inserting an expiration field into the cookie contained in a network response packet. Additionally, a mechanism is provided to delete or damage a cookie contained in a network request packet, so that server software is not disrupted by the receipt of a cookie. Deleting a cookie results in a cleaner request, but damaging a cookie may be more efficient in certain circumstances. By providing these features, an efficient cookie switching design is provided.

Abstract: An isolation switch blade Fiber Channel switch presents F_ports to form a first Fiber Channel fabric and N_ports to a second Fiber Channel fabric to appear as node devices. The isolation switch blade may be used to connect a plurality of blade servers to a Fiber Channel fabric. Fabric events engendered by the insertion or removal of hot-pluggable devices are handled by the isolation switch blade and “event storms” on the Fiber Channel fabric are avoided. The isolation switch blade presents the blade servers to the FC fabric as a virtualized N_port.

Abstract: A network configuration device or entity has control of defined management and security functions in the network, or in many embodiments, in a Fiber Channel fabric. The network configuration device may control many functions. Foremost, it may control the recognition, operation and succession procedure for network configuration entities. It may also control user configurable options for the network, rules for interaction between other entities in the network, rules governing management-level access to the network, and rules governing management-level access to individual devices in the network. In addition, the network configuration entity may exploit policy sets to implement its control.

Abstract: A multi-processor architecture for a network device that includes a plurality of barrel cards, each including: a plurality of processors, a PCIe switch coupled to each of the plurality of processors, and packet processing logic coupled to the PCIe switch. The PCIe switch on each barrel card provides high speed flexible data paths for the transmission of incoming/outgoing packets to/from the processors on the barrel card. An external PCIe switch is commonly coupled to the PCIe switches on the barrel cards, as well as to a management processor, thereby providing high speed connections between processors on separate barrel cards, and between the management processor and the processors on the barrel cards.

Abstract: The snapshot capability moving into the SAN fabric and being provided as a snapshot service. A well-known address is utilized to receive snapshot commands. Each switch in the fabric connected to a host contains a front end or service interface to receive the snapshot command. Each switch of the fabric connected to a storage device used in the snapshot process contains a write interceptor module which cooperates with hardware in the switch to capture any write operations which would occur to the snapshot data area. The write interceptor then holds these particular write operations until the original blocks are transferred to a snapshot or separate area so that the original read data is maintained. Should a read operation occur to the snapshot device and the original data from requested location has been relocated, a snapshot server captures these commands and redirects the read operation to occur from the snapshot area.

Abstract: A network device includes a plurality of blades, each having a plurality of CPU cores that process requests received by the network device. Each blade further includes an accumulator circuit. Each accumulator circuit periodically aggregates the local counter values of the CPU cores of the corresponding blade. One accumulator circuit is designated as a master, and the other accumulator circuit(s) are designated as slave(s). The slave accumulator circuits transmit their aggregated local counter values to the master accumulator circuit. The master accumulator circuit aggregates the sets of aggregated local counter values to create a set of global counter values. The master accumulator circuit transmits the global counter values to a management processor (for display), to the CPU cores located on its corresponding blade, and to each of the slave accumulator circuits. Each slave accumulator circuit then transmits the global counter values to the CPU cores located on its corresponding blade.

Abstract: A system, method and apparatus for providing multiple access modes in a data communications network includes a network access device having a plurality of input ports, a plurality of output ports, and a switching fabric for routing data received on the plurality of input ports to at least one of the plurality of output ports. Control logic within the network access device is adapted to determine whether a user device coupled to one of the plurality of input ports supports a user authentication protocol used by a host network. If the user authentication protocol is not supported, then the input port to which the network access device is coupled is placed in a semi-authorized access state that limits access to a pre-configured network accessible via the host network.

Abstract: A system including a storage processing device with an input/output module. The input/output module has port processors to receive and transmit network traffic. The input/output module also has a switch connecting the port processors. Each port processor categorizes the network traffic as fast path network traffic or control path network traffic. The switch routes fast path network traffic from an ingress port processor to a specified egress port processor. The storage processing device also includes a control module to process the control path network traffic received from the ingress port processor. The control module routes processed control path network traffic to the switch for routing to a defined egress port processor. The control module is connected to the input/output module. The input/output module and the control module are configured to interactively support data virtualization, data migration, data journaling, and snapshotting.

Abstract: A cooling system for rack mount electrical or electronic equipment comprises a hollow, box-shaped exhaust shelf having a vent on at least one end face thereof. The exhaust shelf may be configured for rack mounting. A side duct, open on its inner side, is mounted between the exhaust shelf and a top rail adapted to be mounted between a front post and an opposing rear post in a four-post rack mount enclosure. A plenum in the side duct is in fluid communication with the interior chamber of the exhaust shelf. A chassis having a side-facing exhaust for cooling air may be mounted on or over the exhaust shelf such that warm air exiting the chassis is collected in the plenum of the side duct and channeled into the exhaust shelf and out through the vent. In this way, the desired front-to-back cooling air flow within a rack mount enclosure may be maintained even if one or more individual chassis mounted in the enclosure have side cooling air exhausts.

Abstract: Virtual channels are used to improve quality of service through a large port count switch. Data frames are sent from one small switch to another small switch within the large port count switch on virtual channels. The use of virtual channels helps prevent congestion caused by a first external source device sending data to a first external destination device from affecting a second external source device sending data to a second external destination device.

Abstract: In a network, a user can configure host-level policies usable for load balancing traffic to servers of a domain. A global server load balancing (GSLB) switch provides load balancing to the servers, and is configured with the GSLB host-level policies. Users can define a host-level policy (alternatively or additionally to a globally applied GSLB policy) and apply the host-level policy to hosts in domains configured on the GSLB switch. Thus, the user can enable different policies for different hosts. This allows the user to have the flexibility to control metrics used for selection of a best address for querying clients, as well as the metric order and additional parameters used in the GSLB process, at the host level.

Abstract: A switch may be used to force the expiration of a cookie on a user's system by inserting an expiration field into the cookie contained in a network response packet. Additionally, a mechanism is provided to delete or damage a cookie contained in a network request packet, so that server software is not disrupted by the receipt of a cookie. Deleting a cookie results in a cleaner request, but damaging a cookie may be more efficient in certain circumstances. By providing these features, an efficient cookie switching design is provided.

Abstract: Methods for efficiently managing a ternary content-addressable memory (TCAM) by minimizing movements of TCAM entries include determining a first node and a second node in the TCAM, determining if there is a free TCAM entry between the first node and the second node, and storing the new entry in the free TCAM entry. Upon determining that a free TCAM entry does not exist between the first node and the second node, further determining a chain of nodes and then determining if there is a free TCAM entry in the chain of nodes. Upon determining that there is a free TCAM entry within the chain of nodes, moving the TCAM entries identified as the nodes in the chain of nodes to generate a free node nearest to the new entry and inserting the new entry in the free node. Moving the TCAM entries identified as the nodes in the chain of nodes preserves the order of the nodes.

Abstract: A stackable device having a plurality of data ports, wherein each of the data ports is capable of operating as a regular data port or a stacking port. A first set of one or more of the data ports is specified as a first flexible stacking port, and a second set of one or more of the data ports is specified as a second flexible stacking port. Each flexible stacking port can be individually configured to operate as an actual stacking port, if required by the configuration of an associated stack. If a flexible stacking port is not configured to operate as an actual stacking port, then the data port(s) included in the flexible stacking port are available to operate as regular data port(s).

Abstract: A system and method that modifies the behavior of the IEEE 802.1D STP standard to thereby decouple the one data domain from the one control domain involves managing multiple spanning tree protocol (STP) instances in a virtual local area network (VLAN). The method includes the step of assigning a unique set of ports within the VLAN to each of the multiple STP instances. Then, each of the multiple STP instances are managed to keep each of the multiple STP instances separate. Finally, when a topology change is detected in one of the multiple STP instances, entries that have been learned on the unique set of ports assigned to the STP protocol instance where the topology change is detected are fast-aged or transitioned from one state to another.

Abstract: File system disaster recovery techniques provide automated monitoring, failure detection and multi-step failover from a primary designated target to one of a designated group of secondary designated targets. Secondary designated targets may be prioritized so that failover occurs in a prescribed sequence. Replication of information between the primary designated target and the secondary designated targets allows failover in a manner that maximizes continuity of operation. In addition, user-specified actions may be initiated on failure detection and/or on failover operations and/or on failback operations.

Abstract: A method of configuring a stack includes: connecting stacking ports of a plurality of stackable devices using one or more stacking links; connecting a user console to a first one of the stackable devices; transmitting a stack setup command from the user console to the first stackable device; and establishing a stack in response to the stack setup command. The stack is established by initiating a discovery process with the first stackable device in response to the stack setup command, wherein the first stackable device requests and receives identifying information from the stackable devices over the stacking links during the discovery process. The topology of the stackable devices is displayed with the user console in response to the identifying information. The stackable devices are authenticated during the discovery process such that the stack setup is secure. The first stackable device becomes the active controller of the stack by default.