Cisco Technology, Inc.

Dezhong Cai

Ali Sajassi

Simon Chatterjee

Christopher M North

Clarence Filsfils

Roberto Mitsuo Kobo

Sanjeev Debdutta Rampal

Praveen Bhagwatula

Simon James Trevor Spraggs

Gopakumar Choorakkot Edakkunni

Yongkui Han

Saikat Ray

Simon P Chatterjee

In one embodiment, a method is described. The method includes receiving a network communication at a first network device coupled to a first network and a second network, determining whether to forward the network communication into the first network over a logical connection, and, if the network communication is to be forwarded into the first network over the logical connection, forwarding the network communication into the first network over the logical connection. The network communication comprises a first network address in the second network that is associated with a second network device coupled to the second network. The logical connection is associated with a second network address in the second network. The determining is based, at least in part, on a determination, as to whether the first network device and the second network device are coupled to the logical connection, that uses the first network address and the second network address.

Method and system for asymmetric redundancy mechanisms in multi-homed network access topologies

In one embodiment, a method is described. The method includes receiving a network communication at a network device of a redundancy group. The redundancy group comprises a plurality of network devices, and the plurality of network devices are addressed in a first network using an anycast address. The method further includes, if the network communication is received from the first network, forwarding the network communication into a second network. If the network communication is received from the second network, the method determines whether to forward the network communication into the first network based on a status of the network device in the redundancy group, and a result of a filtering operation.

In one embodiment, a device-independent label is associated with multiple network devices such that the packet switching devices in a network will forward a packet based on the device-independent label to one of these multiple network devices. In one embodiment, these device-independent labels include, but are not limited to, domain-identifying labels and forwarding-punt labels. In one embodiment, a domain-identifying label is defined as a label that identifies a plurality of network nodes without identifying a single particular network node, single particular interface, nor single particular link. In one embodiment, a first-domain forwarding-punt label is placed at the top of the label stack to identify to forward the label-switched packet to any one of a plurality of designated forwarding nodes corresponding to the first-domain forwarding-punt label (e.g., for sending to a packet switching device which will have forwarding information for the second domain-identifying label).

Label-switched packets with device-independent labels

According to one embodiment, a first message identifying a best root node of a spanning tree may be generated. The spanning tree may be implemented by an access domain. The message may be generated independently of a spanning tree protocol instance. The first aggregation node may transmit the first message to a plurality of access nodes of the access domain. Data traffic from the plurality of access nodes may be received. Each access node of the plurality of access nodes may implement a spanning tree protocol instance that selects the best root node as a root node of the spanning tree. The data traffic may be aggregated with other data traffic of a plurality of access domains, and the aggregated data traffic transmitted to an aggregation network.

Aggregating data traffic from access domains

In one embodiment, a negotiation is performed between each adjacent pair of a plurality of packet switching devices in a ring network to determine an Internet Protocol (IP) subnet to be used for communicating between said packet switching devices of said adjacent pair. Packets are communicated by said packet switching devices of said adjacent pair using a different IP address of said determined IP subnet. In one embodiment, each of the plurality of packet switching devices is initially assigned an IP subnet to use on one of its two interfaces participating in the ring network; and wherein said negotiation determines which of said two interfaces will use said initially assigned IP subnet.

Automatic assignment of internet protocol addresses in a ring network

In one embodiment, a packet switching device includes one or more host devices and a cascade of aggregation nodes. The aggregation nodes aggregate customer traffic and communicate it with the host device. Typically the aggregation nodes are remotely located from the host device. The host device may be connected to one or both ends of the cascaded topology of aggregation nodes. In one embodiment, the cascaded topology of aggregation nodes automatically configures itself using initiation packets. In one embodiment, the cascaded topology of aggregation nodes reacts to detected faults, such as by changing direction packet traffic is sent through the cascaded topology. By cascading aggregation nodes, in contrast to having each aggregation node connected to the host device via one or more point-to-point links, communications costs are decreased in one embodiment.

Packet switching device including cascaded aggregation nodes

Embodiments herein generally provide techniques for upgrading a virtual router (VR) comprising first and second physical routers used to route data between network devices. Before upgrade the first physical router, one or more ports of the router are disabled which causes data paths previously flowing through the first router to flow through the second router. After performing the upgrade, the first router is rebooted and uses a unique router ID to discover the network topology of an external network coupled to the VR. Once the network topology is identified, the first router activates a routing application (e.g., a BGP routing application) which enables the router to process control plane traffic received from the second router. Once routing information is gathered, the first router is able to assume the responsibility of forwarding data packets in the network, thereby freeing the second router to be upgraded.

Virtual router upgrade via graceful restart

In one embodiment, a method includes receiving configuration data at a particular node of a first set of multiple nodes. The configuration data includes data that indicates a particular zero or more instances for which the particular node is primary among multiple virtual local area network (VLAN) instances to be forwarded. It is determined whether a VLAN indicated in a data packet received at the particular node is included in the particular instances for which the particular node is primary. If so, then the data packet is forwarded. In another embodiment, multiple nodes are configured to perform as a single virtual node, and the single virtual node is configured to forward data packets for the multiple VLAN.

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San Jose, CA, United States of America

Dezhong Cai