Abstract: In one embodiment, a technique for routing traffic in networks represented by logical topologies, such as Multi Chassis Port Channel (MCPC) or Multi Chassis Ether Channel (MCEC) topologies, is provided. By modifying a port priority vector (PPV) to include an additional “Switch ID” field that identifies a designated bridge ID or a local switch ID, depending on whether the corresponding port is used as an MCT, a routing protocol designed to avoid loops in routing paths, such as STP, may avoid blocking MCT ports.

Abstract: In one embodiment, an indication of a fault condition is received relating to a first service running on a physical device in a computer network. The first service is associated with a first virtual device context defined on the physical device. Then, the first service is disabled without affecting operation of a second service on the physical device. The second service is associated with a second virtual device context defined on the physical device. In another embodiment, a first virtual device context is created on a physical device in a computer network. Then, a second virtual device context is created on the physical device. The first virtual device context may then be managed independently of the second virtual device context such that resources assigned to a virtual device context are managed without affecting management of another virtual device context.

Abstract: A method is provided in one example embodiment and includes receiving a spanning tree protocol topology change notification (STP TCN) in a network; removing topology data for a first plurality of gateways associated with a first network segment ID that is shared by a particular gateway that communicated the STP TCN; and communicating an edge TCN to a second plurality of gateways associated with a second network segment ID and for which topology data has not been removed based on the STP TCN.

Abstract: In one embodiment, an indication of a fault condition is received relating to a first service running on a physical device in a computer network. The first service is associated with a first virtual device context defined on the physical device. Then, the first service is disabled without affecting operation of a second service on the physical device. The second service is associated with a second virtual device context defined on the physical device. In another embodiment, a first virtual device context is created on a physical device in a computer network. Then, a second virtual device context is created on the physical device. The first virtual device context may then be managed independently of the second virtual device context such that resources assigned to a virtual device context are managed without affecting management of another virtual device context.

Abstract: A Fibre Channel switch and related methods are provided for a relative addressing scheme for domain values used by the switch to avoid losing other portions of a Fibre Channel identifier if a particular run-time domain becomes invalid. At a Fibre Channel switch, data is stored that assigns a relative domain field value to a run-time domain in one of a plurality of virtual storage area networks. The relative domain field value used for a Fibre Channel identifier is determined for each of a plurality of devices connected to the Fibre Channel switch based on the run-time domain of the respective devices and the virtual storage area network in which the respective devices are active. A Fibre Channel identifier is stored in a memory of the Fibre Channel switch for each of the plurality of devices. The Fibre Channel identifier comprises the relative domain field value determined for the device together with area and port values for the device.

Abstract: Methods and apparatus for providing in-order delivery in Fibre Channel (FC) fabric are disclosed. A topological change between a first switch and a second switch is evaluated to determine whether the topological change may result in out-of-order delivery. If it is determined that the topological change may result in out-of-order delivery, a flush frame is sent to the second switch and stop-on-mark is performed on all interfaces of affected links. Upon receiving the flush frame, the second switch drains all virtual output queues (VOQs) and sends an acknowledgement frame to the first switch. The first switch resumes in-order-delivery in an affected link after receiving the acknowledgement frame or expiration of a lifetime time of a frame.

Abstract: In one embodiment, a technique for returning Domain IDs to a Fibre Channel fabric without a full build fabric (BF) phase is provided. A switch in the fabric may send a principal switch a message requesting the return of one or more Domain IDs assigned to that device. The principal switch may update the list of fabric Domain IDs to remove the Domain IDs identified in the message and send the updated list to devices in the fabric.

Abstract: In one embodiment, a first switch is located at a first border between first networks that utilize a STP to detect and break loops and second networks. The first switch is interconnected via the first networks with a second switch located at a second border between the first networks and the second networks. The first switch detects, via a protocol other than STP, addition of a link in the second networks that provides a new path across the second networks between the first switch and the second switch. The first switch blocks data packets from traversing through one or more network boundary ports of the first switch coupled to the first networks, while allowing STP BPDUs to traverse through the one or more network boundary ports, for a period of time sufficient for the first networks to discover the new path using STP.

Abstract: In one embodiment, the convergence node switches of a destination node switch in a network having multiple equal paths between a source switch and destination switch are identified. When a new equal cost path is added to the network, packets are flushed up to the convergence node switch closest to the source switch.

Abstract: In one embodiment, a technique for returning Domain IDs to a Fibre Channel fabric without a full build fabric (BF) phase is provided. A switch in the fabric may send a principal switch a message requesting the return of one or more Domain IDs assigned to that device. The principal switch may update the list of fabric Domain IDs to remove the Domain IDs identified in the message and send the updated list to devices in the fabric.

Abstract: In one embodiment, a first switch at a border between a first network of a first protocol (P1 network) and a first network of a second protocol (P2 network) is interconnected via the first P1 network with a second switch between a second P1 network (interconnected with the first P1 network) and a second P2 network. In response to detecting a merge of the first and second P2 networks, the first switch may: i) block data packets from traversing P1 network boundary ports of the first switch; ii) allow protocol messages to flow between the first and second P1 networks through the P1 network boundary ports of the first switch; iii) allow the first and second P1 networks to discover each other through the protocol messages and to prevent loops; and in response, iv) unblock the P1 network boundary ports of the first switch to allow traversal of data packets.

Abstract: In one embodiment, a solution is provided wherein multiple virtual devices may be configured on the same physical port of a network device. For example, a first virtual device and a second virtual device may be configured to use the same physical port. A single internal spanning tree instance may be configured for both the first virtual device and the second virtual device.

Abstract: In one embodiment, a method includes establishing a link between two N_Port Identifier Virtualization (NPIV) switches, the link having a high cost assigned thereto. The NPIV switches are in communication with a plurality of hosts through an N_Port Virtualization (NPV) device. The method further includes receiving at a first of the NPIV switches, an indication of a failure at a second of the NPIV switches, receiving data at the first NPIV switch, the data destined for one of the hosts associated with a domain of the second NPIV switch, and forwarding the data to the NPV device for delivery to the host, wherein a Fibre Channel Identifier (FCID) of the host is the same before and after the failure at the second NPIV switch. An apparatus is also disclosed.

Abstract: Certain embodiments of the present disclosure generally relate to allocating a sub-area of Fibre Channel addresses (FCIDs) to a device. A range of addresses may be assigned to the device using a mask address, where the most significant bits represent a mask and the least significant bits represent a sub-range of FCIDs available to be assigned to the device. Therefore, routing information may be stored efficiently in a Ternary Content Addressable Memory (TCAM) by storing a single entry in the TCAM for each sub-area of FCIDs allocated to a device, instead of storing an entry for each FCID. The single entry may indicate the mask address and the width of the mask.

Abstract: The number of domain identifiers is incrementally increased for use by a switch in an established fibre channel switched fabric. In other words, the number of domains assigned to a switch by the Principal Switch of the fibre channel switched fabric is increased without triggering the reconfiguration of the established fibre channel switched fabric. In one implementation, incrementally adding one or more additional domain identifiers includes requesting said one or more additional domain identifiers from a Principal Switch of the fibre channel switched fabric using a different World Wide Name (WWN) than used to acquire the original one or more domain identifiers used by the switch.

Abstract: In one embodiment, a solution is provided wherein multiple virtual devices may be configured on the same physical port of a network device. For example, a first virtual device and a second virtual device may be configured to use the same physical port. A single internal spanning tree instance may be configured for both the first virtual device and the second virtual device.

Abstract: Systems, methods, and other embodiments associated with computing path costs based on link cost as a primary metric and hop cost as a secondary metric are presented. The secondary metric facilitates distinguishing between what would be equal cost multi-paths if only link cost was employed. One example method includes computing a modified link cost for a plurality of paths between switches. The example method may also include determining a lowest modified link cost associated with a path between the switches. The example method may also include providing a signal identifying the lowest modified link cost.

Abstract: In one embodiment, a method includes receiving at a processor at a node, notification of an error in a VLAN to topology mapping at the node, receiving a multi-destination packet from the VLAN in the VLAN to topology mapping, the multi-destination packet including a tree identifier associated with one of the topologies, and transmitting the multi-destination packet to all forwarding ports at the node in an unpruned tree corresponding to the tree identifier contained in the multi-destination packet. An apparatus is also disclosed.

Abstract: A method and apparatus for preventing loops in a network with network devices operating a spanning tree protocol and network devices operating a link state routing protocol to prevent loops are disclosed. In one embodiment, a method includes receiving from one of the network devices operating a link state protocol, a link state routing synchronization packet at a first network device in communication with one of the network devices operating the spanning tree protocol, blocking at the first network device, boundary ports in communication with the network devices operating the spanning tree protocol, transmitting a link state routing synchronization acknowledgement packet at the first network device after the boundary ports are blocked, and performing a loop-free topology convergence process at the first network device.

Abstract: In one embodiment, a method includes obtaining an indication that a state associated with a node is to be changed and preventing data from being received on a first link. The method also includes updating at least one selected from a group including an incoming interface check (IIC) table and an outgoing interface (OIF) table to reflect the state. The state indicates that a second link is to be activated. Finally, the method includes allowing the data to be received on the second link after updating either or both the IIC table and the OIF table and after the timer duration for the NULL value for IIC has expired.