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: Methods and apparatus for source rooted multicast (SRM) are provided. As defined herein, SRM generally refers to associating outgoing interface lists (OILs) in the forwarding entry with the source address instead of the group address and aggregating the resulting multicast forwarding states. In this manner, the amount of forwarding state may be reduced, especially in deployments where many hosts are all running the same application and using the same group. One example method generally includes—for each of a plurality of multicast forwarding states associated with a multicast group, wherein each multicast forwarding state is referenced by a source address representing a multicast source and is associated with an outgoing interface list—associating the outgoing interface list with the source address; and aggregating the two or more of the multicast forwarding states having the outgoing interface lists associated with the source addresses to form one or more aggregated forwarding states.

Abstract: Devices, methods and instructions encoded on computer readable medium are provided herein for creation of an overlay network on a non-multicast or source specific multicast (SSM) core. In one example, virtual private network (VPN) adjacencies are established between an adjacency server and one or more edge devices each located at different network sites. A unicast replication list is then generated at the adjacency server. The unicast replication list includes the Internet Protocol addresses for each of the edge devices having VPN adjacencies with the adjacency server. The unicast replication list is then advertised to each of the edge devices for use in establishing VPN adjacencies with one another.

Abstract: In one embodiment, an apparatus includes a plurality of network site interfaces in communication with two or more networks, each of the networks associated with a different Virtual Routing and Forwarding (VRF) instance, and a processor configured for mapping the VRF instances to an Interior Gateway Protocol (IGP) adjacency and transmitting VRF information on the IGP adjacency along with a VRF identifier indicating the network associated with the VRF information. A method is also disclosed.

Abstract: Systems and methods for automatically controlling efficient operation of a plurality of network appliances operatively linked and networked to balance network traffic load across a plurality of network appliances that are selectively enabled. The system facilitating performance of the method includes at least a plurality of network appliances operatively connected to a switch and controlled by a network access control module. During system operation, at any given moment in time, the plurality network appliances operate in one of two modes, fully operational or stand-by. The network appliances of the plurality that are fully operational and thereby consuming full operational power depends upon the network traffic load at any given moment in time. The network appliances functioning in a stand-by mode consume low power levels which are sufficient to allow a network appliance in stand-by mode to receive a command signal directing it to switch from stand-by to full operational mode.

Abstract: Methods and systems may be provided for installing a route entry associated with multicast traffic to a memory. Client devices may be notified of the route entry for advertisement by an active source device. The delivery group and delivery source may be retrieved from the information for the route entry. Multicast data trees may maintain delivery group and delivery source information for access.

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: In one embodiment, a method includes receiving information on layer 2 topologies at a network device in a core network, mapping one or more Virtual Local Area Networks (VLANs) to the layer 2 topologies to provide differentiated services in said layer 2 topologies, defining multiple paths for each of the layer 2 topologies, and forwarding a packet received at the network device on one of the multiple paths. An apparatus and logic for providing differentiated services in layer 2 topologies is also disclosed.

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: In one embodiment, a method includes receiving information on layer 2 topologies at a network device in a core network, mapping one or more Virtual Local Area Networks (VLANs) to the layer 2 topologies to provide differentiated services in said layer 2 topologies, defining multiple paths for each of the layer 2 topologies, and forwarding a packet received at the network device on one of the multiple paths. An apparatus for providing differentiated services in layer 2 topologies is also disclosed.

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: Various techniques for exchanging control messages in order to gracefully reroute multicast traffic are disclosed. For example, one method involves sending a join message for a multicast group towards a root of a new multicast tree and forwarding multicast traffic, addressed to the multicast group, on a current multicast tree until an acknowledgment corresponding to the join message is received. The new multicast tree can be identified in response to detection of a topology change within the network. Until the acknowledgment is received, multicast traffic that is received via the new multicast tree can be dropped.

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: In one embodiment, an apparatus includes one or more internal interfaces in communication with one or more network devices in a first network site through a Layer 2 link, an overlay interface in communication through a Layer 3 link with a core network connected to one or more other network sites, and a table mapping addresses for network devices in the other network sites to addresses of edge devices in the same network site as the network device. The apparatus further includes a processor operable to encapsulate a packet received at one of the internal interfaces and destined for one of the network devices in the other network sites, with an IP header including a destination address of the edge device mapped to the destination network device, and forward the encapsulated packet to the core network.

Abstract: A provider edge (PE) node of a network operates to send a trace path message over the network to a receiver PE node, the trace path message recording a list of intermediate nodes of a unicast path from the PE node to the receiver PE node; and receive a join message initiated from the receiver PE node, the join message using the list to propagate to the source PE node through the intermediate nodes such that a branch of a multicast tree is aligned with the unicast path. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: In one embodiment, an apparatus includes one or more internal interfaces in communication with one or more network devices in a first network site through a Layer 2 link, an overlay interface in communication through a Layer 3 link with a core network connected to one or more other network sites, and a table mapping addresses for network devices in the other network sites to addresses of edge devices in the same network site as the network device. The apparatus further includes a processor operable to encapsulate a packet received at one of the internal interfaces and destined for one of the network devices in the other network sites, with an IP header including a destination address of the edge device mapped to the destination network device, and forward the encapsulated packet to the core network.

Abstract: Various techniques for exchanging control messages in order to gracefully reroute multicast traffic are disclosed. For example, one method involves sending a join message for a multicast group towards a root of a new multicast tree and forwarding multicast traffic, addressed to the multicast group, on a current multicast tree until an acknowledgment corresponding to the join message is received. The new multicast tree can be identified in response to detection of a topology change within the network. Until the acknowledgment is received, multicast traffic that is received via the new multicast tree can be dropped.

Abstract: Systems and methods for implementing a bidirectional multicast protocol with two types of join messages are disclosed. The two types of join messages, upstream joins and downstream joins, are used to control the Reverse Path Forwarding (RPF) interface is added to the outgoing interface list for a particular multicast group, which in turn controls when multicast packets will be forwarded to the rendezvous point. One method involves receiving a multicast packet addressed to multicast group G. The method inhibits the multicast packet from being forwarded via the RPF interface, unless the outgoing interface list corresponding to the multicast group G already identifies the RPF interface. The RPF interface can be added to the outgoing interface list in response to reception of a downstream join message via the RPF interface, as well as in response to monitoring, via the RPF interface, an upstream join message on a shared network segment.

Abstract: A data structure is stored in a memory of a router, the router located along a path between a source end station and a plurality of destination end stations in a multicast distribution tree. In response to receipt of trace packets containing a listing of network devices in the multicast distribution tree, the data structure is updated. When the source end station desires to send a multicast packet, it transmits a packet to the router. The router then writes the path information stored in the data structure into the packet. Such path information may include a tree list that specifies the arrangement of network devices along the multicast distribution tree and an address list that specifies the Internet Protocol (IP) addresses of these network devices along the multicast distribution tree. By storing the complete description of the network devices of the multicast distribution tree in the packet, routing demands on the devices along the multicast path are minimized.

Abstract: Various systems and methods for rerouting multicast traffic in response to detecting imminent network disruption are disclosed. One method involves detecting an imminent topology change and, in response, identifying a new multicast distribution tree for a multicast group. A join message for the multicast group is then sent towards a root of the new multicast distribution tree. Multicast traffic addressed to the multicast group continues to be forwarded via the current multicast distribution tree, subsequent to sending the join message. The multicast traffic is not forwarded via the new multicast distribution tree until one or more multicast data packets have been received via the new multicast distribution tree.