Cisco Technology, Inc.

Donnie Van Savage

Thuan Van Tran

Yi Yang

Alvaro E Retana

Russell Ivan White

James L Ng

Liem Hong Nguyen

Donald Earl Slice, Jr

Steven Edward Moore

Donald Slice

Timothy M Gage

Rajiv Asati

Mohamed Khalid

Pratima Pramod Sethi

Roy Michael Brooks

Stanley M Ratliff

Matthew Henry Birkner

Mihail L Sichitiu

Stefano Giorcelli

Graham Geoffrey Gudgin

Russ White

Timothy Charles Schuler

Gregory Edwards

A system and method for facilitating connecting a switch to a network to improve network performance. In an illustrative embodiment, the system includes a first module for determining when the switch is initially connected to a network and providing a signal in response thereto. A second module selectively forms adjacencies with peers of the switch in response to the signal and based on one or more predetermined parameters. In a more specific embodiment, the switch is a router or Layer-3 (L3) switch. The one or more predetermined parameters include a load factor, values pertaining to capabilities of a processor included in the router, bandwidth capabilities of the interface and/or the router, internal router queue counts, and so on. The router employs a routing protocol such as Enhanced Interior Gateway Routing Protocol (EIGRP). The second module throttles and adjacency-formation rate based on the predetermined parameters.

System and method for enhancing network stability by selectively controlling adjacency formation

Systems and methods for using routing protocol extensions to improve spoke to spoke communication in a computer network are disclosed. Embodiments provide systems and methods to establish a tunnel between a first spoke and a hub, exchange routing information between the first spoke and the hub using a routing protocol, extend the routing protocol and an associated database to include next hop mapping information, and establish a tunnel between the first spoke and a second spoke according to information in the database.

System and method for using routing protocol extensions for improving spoke to spoke communication in a computer network

Methods and apparatus for allowing a traffic level switch associated with an automatic protection switching (APS) topology to occur transparently and without reconverging routing are described. According to one aspect of the present invention, a method for providing protection switching configuration information associated with a router arrangement to includes identifying a first interface and a second interface of the router arrangement as an APS group. The method also includes providing information regarding the APS group to a process that implements a routing protocol. Providing the information regarding the group includes identifying the first interface as a primary interface and identifying the second interface as a backup interface that is arranged to protect the primary interface.

Transparent automatic protection switching for a chassis deployment

Techniques are disclosed for synchronizing a database related to a first node in a network with multiple nodes. Each node includes a database different from a database on a different node. An inquiry control message is sent to each node in a candidate set of one or more nodes on the network, which are different from the first node. In response to the inquiry control message, the first node receives a first set of one or more messages from a particular node different from the first node. The first set indicates a portion from the database of the particular node. The portion is relevant for the first node. A particular portion of a first database for the first node is derived from the first set of messages. The particular portion is less than all of the first database. These techniques allow the first node to derive its full database from multiple adjacent nodes.

Synchronizing portions of a database with different databases on different nodes of a network

A system for optimizing the performance of a network. In an illustrative embodiment, the system includes a memory containing one or more data structures data structures. A first module determines transit-only information. A second module selectively omits the transit-only information from the one or more data structures. In a more specific embodiment, the one or more data structures include one or more tables. The transit-only information includes interface Internet Protocol (IP) addresses associated with network interfaces that are transit-only interfaces. The route information may include network topology information. The one or more tables may include a network topology table. Plural routers positioned in the network incorporate one or more instances of the system. The routers may employ one or more routing protocols, such as include Enhanced Interior Gateway Routing Protocol (EIGRP) or Routing Information Protocol (RIP).

System and method for improving network performance and security by controlling topology information

In one embodiment, a method for using a two-hop relay includes receiving an update message for a distance vector routing protocol from a first neighbor. The update message is sent to a different neighbor. Often, it is first determined whether the receiving node is a relay node for the first neighbor in the protocol. The relay node is a node preferred to update a particular node two hops from the first neighbor. In another embodiment, a method for serving as the two-hop relay includes receiving from each neighbor a first message that includes neighbor data that indicates nodes that are in direct communication with the neighbor. A relay set of fewer than all neighbors is determined. Every node two hops from the first node is updated using only the relay set of neighbors. The relay set is sent in a second message for the protocol.

Two-hop relay for reducing distance vector routing information

In one embodiment, a method includes identifying at a node, a destination for which a primary path is defined between the node and the destination, transmitting a request message to a neighbor node for routing information for a backup path between the node and the destination, receiving a reply message containing an address identifying the backup path, and building a backup tunnel to the address. The request message includes at least one node identified as a node to be avoided in the backup path and a request cost. An apparatus for building backup tunnels is also disclosed.

Building backup tunnels for fast reroute in communications networks

A system and method for enhancing the behavior of a network. In an illustrative embodiment, the network includes a distribution router and plural additional routers connected to the distribution router. The system includes a first module that is adapted to characterize the additional routers as stub routers or non-stub routers and then to provide a signal in response thereto. A second module selectively queries non-stub routers for route information and does not query stub routers for the route information. In a more specific embodiment, the second module includes a unicast module for selectively unicasting queries to the non-stub routers. A multicast module selectively multicasts queries to the non-stub routers via a modified conditional-receive algorithm.

System and method for improving network performance by controlling stub-routing behavior

A router identifies transit links and non-transit links. Only the non-transit links are advertised as routes to adjacent routers, thereby protecting the transit links from edge traffic which terminates on a network on one of the transit links. In another aspect of the invention, an administrative whitelist supplements the routes which identify the transit link network routes. In another aspect of the invention, a method for advertising routes identifies entries in a router table as broadcast or point-to-point. Only the router table entries for point-to-point links which are not transit or broadcast links that are not for a neighboring router are advertised, whereas the point-to-point transit links or broadcast transit links are advertised as transit links if an administrative whitelist is enabled.

Protection of transit links in a network

Techniques for synchronizing routing data include determining whether conditions are satisfied for one-way transfer with an adjacent router. If it is determined that conditions are satisfied for one-way transfer of routing table data with the adjacent router, then a refresh-notice message is sent from the initiating router to the adjacent router. The refresh-notice message includes data that indicates a particular direction for transfer of routing table data. If the particular direction is inbound, then a copy of an adjacent routing table is received without sending a copy of the initiating router's own routing table. If the particular direction is outbound, then a copy of the own routing table is sent without receiving a copy of the adjacent routing table.

Techniques for one-way synchronization of routing information among intermediate nodes

In one embodiment, a method includes receiving a first update message at a first forwarding node from a second forwarding node of the communications network. The first update message includes forwarded service type data that indicates a type of service available via the second forwarding node, and forwarded cost data that indicates a first cost of communications to obtain the type of service via the second forwarding node. An incremental cost is determined for communications between the first forwarding node and the second forwarding node. Service data is stored at the first forwarding node. The service data indicates the type of service is associated with the second forwarding node at a total cost based on the first cost and the incremental cost. A second update message that includes forwarded cost data based on the total cost is sent over the network from the first forwarding node.

Service advertisement framework (SAF) in a communications network

A first router is configured for monitoring prescribed attributes of an active path connected to the first router, and supplying an update message to a second router, according to a prescribed routing protocol such as Enhanced Interior Gateway Routing Protocol (EIGRP), that specifies a detected change by the first router in at least one of the prescribed attributes of the connected active path. Hence, the second router, in response to receiving the update message, can update an internal topology table based on the detected change in the active path connected to the first router, and selectively adjust an internal routing table based on the detected change relative to queuing policies for prescribed data flows.

Router configured for outputting update messages specifying a detected attribute change of a connected active path according to a prescribed routing protocol

Techniques for recovering lost routes include receiving reported costs for transmitting data to a destination from neighboring nodes; and determining total costs as a sum of costs for transmitting data packets to the neighboring nodes and a corresponding reported cost. A selected neighboring node with a minimum total cost is determined as the next hop for the route to the destination. A feasible successor set of neighboring nodes which have reported costs less than the total cost of the selected neighboring node and excluding the selected neighboring node, and successor data about the feasible successor set, are determined. The successor data is sent to the neighboring nodes. A neighboring node that loses a route to the particular destination node is able to determine whether to query the sending node while recovering a lost route to the destination based on the successor data, thereby reducing network resource consumption.

Techniques for decreasing queries to discover routes in an interior gateway protocol

Techniques for sending data in a packet-switched communications network include determining multiple subsets of adjacent network nodes of the network. The adjacent network nodes communicate without intervening network nodes with a particular network node through an interface on the particular network node. Each subset includes multiple adjacent network nodes. Subset definition data is sent through the interface. The subset definition data indicates which adjacent network nodes belong to which subset. Data for fewer than all adjacent network nodes in all subsets are sent by including, in a multicast data packet sent over the interface with a multicast destination address, subset identifier data that indicates a particular subset. When such data is received by a node, it is discarded unless the subset identifier matches the receiving node's subset identifier. Among other effects, this allows routing messages to be more efficiently sent to better performing neighboring network nodes.

Growing community of inventors

Raleigh, NC, United States of America

Donnie Van Savage