Russ White, Ph.D.

Problems associated with providing a large Clos network having at least one top of fabric (ToF) node, a plurality of internal nodes, and a plurality of leaf nodes may be solved by: (a) providing L2 tunnels between each of the leaf nodes of the Clos and one or more of the at least one ToF node to ensure a non-partitioned IGP L2 backbone, and (b) identi- fying the L2 tunnels as non-forwarding adjacencies in link state topology information stored in ToF node(s) and leaf node(s) such that the L2… Show more

Problems associated with providing a large Clos network having at least one top of fabric (ToF) node, a plurality of internal nodes, and a plurality of leaf nodes may be solved by: (a) providing L2 tunnels between each of the leaf nodes of the Clos and one or more of the at least one ToF node to ensure a non-partitioned IGP L2 backbone, and (b) identi- fying the L2 tunnels as non-forwarding adjacencies in link state topology information stored in ToF node(s) and leaf node(s) such that the L2 tunnels are not used for forwarding traffic. Show less

The disclosed embodiments provide a system for propagating network configuration policies using a publish-subscribe messaging system. During operation, the system receives, through the publish-subscribe messaging system, one or more messages containing a first representation of a configuration policy from a policy server. Next, the system uses a data model to convert the first representation into a second representation of the configuration policy. The system then uses the second representation… Show more

The disclosed embodiments provide a system for propagating network configuration policies using a publish-subscribe messaging system. During operation, the system receives, through the publish-subscribe messaging system, one or more messages containing a first representation of a configuration policy from a policy server. Next, the system uses a data model to convert the first representation into a second representation of the configuration policy. The system then uses the second representation to apply the configuration policy during processing of network traffic. Show less

The disclosed embodiments provide a system that automatically detects a role of a node in a network with a layered topology. During operation, the system uses a local shortest path tree (SPT) for a node in a network with a layered topology to identify one or more additional nodes in the network that are farthest from the node. Next, the system compares the local SPT with a remote SPT for the one or more additional nodes to identify a position of the node in the layered topology. The system then… Show more

The disclosed embodiments provide a system that automatically detects a role of a node in a network with a layered topology. During operation, the system uses a local shortest path tree (SPT) for a node in a network with a layered topology to identify one or more additional nodes in the network that are farthest from the node. Next, the system compares the local SPT with a remote SPT for the one or more additional nodes to identify a position of the node in the layered topology. The system then outputs the position of the node for use in configuring the operation of the node in the network. Show less

When a change in connectivity is detected in a network, the change is flooded in a link state message from the node that detected the change to all other nodes in the network. In networks with dense topologies, the link state message may be received multiple times by certain nodes, which may increase bandwidth consumption in the networks and processing overhead in the nodes.

One embodiment identifies all one-hop neighbor nodes and two-hop neighbor nodes of a node; determines an active set of one-hop neighbor nodes for the node, comprising: includes in the active set each one-hop neighbor node that is either an edge node or connected with at least one two-hop neighbor node with which no other one-hop neighbor nodes are connected; and if the active set is not yet complete, then: determine all combinations of one-hop neighbor nodes that are not already in the active… Show more

One embodiment identifies all one-hop neighbor nodes and two-hop neighbor nodes of a node; determines an active set of one-hop neighbor nodes for the node, comprising: includes in the active set each one-hop neighbor node that is either an edge node or connected with at least one two-hop neighbor node with which no other one-hop neighbor nodes are connected; and if the active set is not yet complete, then: determine all combinations of one-hop neighbor nodes that are not already in the active set; and tests each combination in order of each combination's total-energy value to determine whether a specific combination is able to complete the active set; if no combination is able to complete the active set, then including all one-hop neighbor nodes in the active set; and communicates a message to each one-hop neighbor node in the active set indicating that it is in the active set. Show less

In an example embodiment, a method and system is provided to determine and advertise a route advertisement in a reactive routing environment. In response to receiving a network address query with respect to a destination address at a routing device, an aggregate value, e.g. an address prefix, is determined and advertised in reply to the network address query. Determining of the aggregate value may comprise identifying within a range of network addresses represented by the aggregate value… Show more

In an example embodiment, a method and system is provided to determine and advertise a route advertisement in a reactive routing environment. In response to receiving a network address query with respect to a destination address at a routing device, an aggregate value, e.g. an address prefix, is determined and advertised in reply to the network address query. Determining of the aggregate value may comprise identifying within a range of network addresses represented by the aggregate value respective addresses for which the routing device does not have reachability information. Show less

One embodiment receives at a first node in at least a portion of a network a routing table, the portion of the network comprising the first node and one or more second nodes, the routing table specifying the immediate neighbor that provides each of the best paths in the portion of the network based on a total cost; using the routing table, determines at the first node every second node that is necessary for the first node to reach all edges of the network, the second nodes that are necessary… Show more

One embodiment receives at a first node in at least a portion of a network a routing table, the portion of the network comprising the first node and one or more second nodes, the routing table specifying the immediate neighbor that provides each of the best paths in the portion of the network based on a total cost; using the routing table, determines at the first node every second node that is necessary for the first node to reach all edges of the network, the second nodes that are necessary for the first node to reach all edges of the network comprising an active set for the first node; and sends a message from the first node to every second node to facilitate determining whether to shut down the second node. Show less

A technique dynamically configures and verifies routing information of broadcast networks using link state protocols in a computer network. According to the novel technique, a router within the broadcast network receives a link state protocol routing information advertisement from an advertising router, e.g., a designated router or other adjacent neighbor.

In one embodiment, each node in a computer network determines a shortest looping ring back to the node through each of its neighbors. Each of these rings may then be marked in a particular direction, ensuring that any ring that shares a link with another ring is marked in such a way that the shared link is in the same direction in each of the rings that share the link. The links that are marked in the particular direction may be stored as part of a first topology. Conversely, the opposite… Show more

In one embodiment, each node in a computer network determines a shortest looping ring back to the node through each of its neighbors. Each of these rings may then be marked in a particular direction, ensuring that any ring that shares a link with another ring is marked in such a way that the shared link is in the same direction in each of the rings that share the link. The links that are marked in the particular direction may be stored as part of a first topology. Conversely, the opposite direction on the links (e.g., bidirectional links or parallel unidirectional links) may be stored as a second topology that is link-disjoint from the first topology. Show less

In an embodiment, a method is provided at which it is used in a device. In this method, a logical identifier assigned to the device is identified and additionally, a mesh group identifier identifying a mesh group is identified. The logical identifier and the mesh group identifier are encoded in a routing message, which is used in an inter-domain routing protocol, and this routing message is transmitted to a reflector device in communication with the device. The reflector device is configured to… Show more

In an embodiment, a method is provided at which it is used in a device. In this method, a logical identifier assigned to the device is identified and additionally, a mesh group identifier identifying a mesh group is identified. The logical identifier and the mesh group identifier are encoded in a routing message, which is used in an inter-domain routing protocol, and this routing message is transmitted to a reflector device in communication with the device. The reflector device is configured to transmit the routing message to a remote device included in the computer network. Show less

In an example embodiment, a method and system is provided to determine and advertise a route advertisement in a reactive routing environment. In response to receiving a network address query with respect to a destination address at a routing device, an aggregate value, e.g. an address prefix, is determined and advertised in reply to the network address query. Determining of the aggregate value may comprise identifying within a range of network addresses represented by the aggregate value… Show more

In an example embodiment, a method and system is provided to determine and advertise a route advertisement in a reactive routing environment. In response to receiving a network address query with respect to a destination address at a routing device, an aggregate value, e.g. an address prefix, is determined and advertised in reply to the network address query. Determining of the aggregate value may comprise identifying within a range of network addresses represented by the aggregate value respective addresses for which the routing device does not have reachability information. The routing device may send address queries with respect to the identified addresses, to determine reachability via the routing device of those addresses. The aggregate value may be advertised conditional upon determining that a percentage of addresses within the corresponding range that can be reached via the routing device satisfies a predefined minimal coverage value. Show less

One embodiment identifies all one-hop neighbor nodes and two-hop neighbor nodes of a node; determines an active set of one-hop neighbor nodes for the node, comprising: includes in the active set each one-hop neighbor node that is either an edge node or connected with at least one two-hop neighbor node with which no other one-hop neighbor nodes are connected; and if the active set is not yet complete, then: determine all combinations of one-hop neighbor nodes that are not already in the active… Show more

One embodiment identifies all one-hop neighbor nodes and two-hop neighbor nodes of a node; determines an active set of one-hop neighbor nodes for the node, comprising: includes in the active set each one-hop neighbor node that is either an edge node or connected with at least one two-hop neighbor node with which no other one-hop neighbor nodes are connected; and if the active set is not yet complete, then: determine all combinations of one-hop neighbor nodes that are not already in the active set; and tests each combination in order of each combination's total-energy value to determine whether a specific combination is able to complete the active set; if no combination is able to complete the active set, then including all one-hop neighbor nodes in the active set; and communicates a message to each one-hop neighbor node in the active set indicating that it is in the active set. Show less

In certain embodiments, performing a defensive procedure involves receiving at a first speaker of a first autonomous system a path advertisement from a second speaker of a second autonomous system. The path advertisement advertises a path from the second speaker of the second autonomous system. It is determined whether the second autonomous system is a stub autonomous system and whether a path length of the path is greater than one. If the second autonomous system is a stub and the path length… Show more

In certain embodiments, performing a defensive procedure involves receiving at a first speaker of a first autonomous system a path advertisement from a second speaker of a second autonomous system. The path advertisement advertises a path from the second speaker of the second autonomous system. It is determined whether the second autonomous system is a stub autonomous system and whether a path length of the path is greater than one. If the second autonomous system is a stub and the path length is greater than one, a defensive measure is performed for the path. Otherwise, a default procedure is performed for the path. Show less

In an embodiment, a method is provided at which it is used in a device. In this method, a logical identifier assigned to the device is identified and additionally, a mesh group identifier identifying a mesh group is identified. The logical identifier and the mesh group identifier are encoded in a routing message, which is used in an inter-domain routing protocol, and this routing message is transmitted to a reflector device in communication with the device. The reflector device is configured to… Show more

In an embodiment, a method is provided at which it is used in a device. In this method, a logical identifier assigned to the device is identified and additionally, a mesh group identifier identifying a mesh group is identified. The logical identifier and the mesh group identifier are encoded in a routing message, which is used in an inter-domain routing protocol, and this routing message is transmitted to a reflector device in communication with the device. The reflector device is configured to transmit the routing message to a remote device included in the computer network. Show less

In an example embodiment, a method is provided. In this method, a network address query is received. A first network address of a known apparatus is retrieved from a routing table, in response to the network address query. A second network address may be determined based upon the network address query, the second network address having a smaller bit length than the first network address. An aggregate value may be advertised that represents a range of reachable network addresses, the range of… Show more

In an example embodiment, a method is provided. In this method, a network address query is received. A first network address of a known apparatus is retrieved from a routing table, in response to the network address query. A second network address may be determined based upon the network address query, the second network address having a smaller bit length than the first network address. An aggregate value may be advertised that represents a range of reachable network addresses, the range of reachable network addresses including the second network address. Show less

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… Show more

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. Show less

A method for communicating packets in a network environment is provided that includes receiving a packet at a network element and identifying a sequence number included in the packet that correlates to awareness information associated with one or more adjacent network elements. A table included in the network element may be updated in order to account for the awareness information included within the packet that has not been accounted for by the network element. In cases where the awareness… Show more

A method for communicating packets in a network environment is provided that includes receiving a packet at a network element and identifying a sequence number included in the packet that correlates to awareness information associated with one or more adjacent network elements. A table included in the network element may be updated in order to account for the awareness information included within the packet that has not been accounted for by the network element. In cases where the awareness information included in the packet has already been accounted for, the packet may be ignored. Show less

The designated forwarding device functionality for forwarding of packets originated on a broadcast link among layer 2 is shared among multiple forwarding devices of different adjacency networks. As these networks do not form adjacencies, the forwarding devices do not natively participate in a same spanning tree for determining how to forward packets, and a designated forwarding device is used for forwarding packets originated on the common broadcast link. Distributing the role of a designated… Show more

The designated forwarding device functionality for forwarding of packets originated on a broadcast link among layer 2 is shared among multiple forwarding devices of different adjacency networks. As these networks do not form adjacencies, the forwarding devices do not natively participate in a same spanning tree for determining how to forward packets, and a designated forwarding device is used for forwarding packets originated on the common broadcast link. Distributing the role of a designated forwarding device among multiple of the forwarding devices provides a means for more efficiently forwarding packets to their destinations. Show less

In one embodiment, a method includes receiving on a first communication link at a local router all routing information at a certain level of detail for each router of multiple routers communicating in a first flooding domain. A measure of distance is determined from a particular router in the first flooding domain to the local router. It is determined whether the measure of distance exceeds a threshold. If the measure of distance exceeds the threshold, then summary routing information with less… Show more

In one embodiment, a method includes receiving on a first communication link at a local router all routing information at a certain level of detail for each router of multiple routers communicating in a first flooding domain. A measure of distance is determined from a particular router in the first flooding domain to the local router. It is determined whether the measure of distance exceeds a threshold. If the measure of distance exceeds the threshold, then summary routing information with less than the certain level of detail is determined for the particular router. Also, certain routing information is sent over a different second communication link at the local router. The certain routing information includes the summary information for the particular router, and all routing information at the certain level of detail for a subset of routers communicating in the first flooding domain, which subset excludes the particular router. Show less

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… Show more

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. Show less

In one embodiment, a system, method, and apparatus for preventing excessive transmission of routing information in a communications network occurs by receiving a network routing address at a connection node in a communications network, the network routing address allowing the transmission of data packets from a source node to a destination node in the communications network; determining a longest summary route covering a path to the destination node; creating a list comprising a summary of all… Show more

In one embodiment, a system, method, and apparatus for preventing excessive transmission of routing information in a communications network occurs by receiving a network routing address at a connection node in a communications network, the network routing address allowing the transmission of data packets from a source node to a destination node in the communications network; determining a longest summary route covering a path to the destination node; creating a list comprising a summary of all neighbor connection nodes of the connection node; and transmitting an update of the longest summary route of the network routing address towards all neighbor nodes advertising a destination address comprising a shorter address prefix, wherein the transmitting process occurs sequentially beginning with a first neighbor connection node entered in the list. Show less

In one embodiment, a method includes sending an adjacency discovery message 1 from a local router over a direct link to a first neighbor router. An adjacency discovery message is not forwarded and includes a repair address. The repair address indicates the local router but is not advertised as reachable over the direct link. An outbound routing update message is sent to a different second neighbor router. The outbound routing update message is forwarded and includes reachability data that… Show more

In one embodiment, a method includes sending an adjacency discovery message 1 from a local router over a direct link to a first neighbor router. An adjacency discovery message is not forwarded and includes a repair address. The repair address indicates the local router but is not advertised as reachable over the direct link. An outbound routing update message is sent to a different second neighbor router. The outbound routing update message is forwarded and includes reachability data that indicates the repair address is reachable. A payload of an inbound tunneled packet received at the local router and directed to the repair address is forwarded based on a destination indicated in the payload. Show less

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… Show more

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. Show less

Each router in a network is configured for generating router advertisement messages according to a flooding distance vector routing protocol. Each router advertisement message output according to the flooding distance vector routing protocol includes reachability information for at least one destination, and an originating router identifier indicating a router having originated the reachability information. If any router receiving the router advertisement message detects a match between the… Show more

Each router in a network is configured for generating router advertisement messages according to a flooding distance vector routing protocol. Each router advertisement message output according to the flooding distance vector routing protocol includes reachability information for at least one destination, and an originating router identifier indicating a router having originated the reachability information. If any router receiving the router advertisement message detects a match between the originating router identifier and the corresponding assigned router identifier, the received router advertisement message is disregarded during calculation of the best paths from the network. If the originating router identifier identifies another router, the router floods the received router advertisement message to other ports, and output its own router advertisement message based on the received router advertisement message and that specifies the originating router identifier from the received router advertisement message. Show less

Techniques for detecting loops in routes that cross route information boundaries include receiving a control message at a first edge node on one side of the boundary that is connected to a different second edge node on another side of the boundary. The control message indicates a particular network address of a particular node that is reachable from the first edge node. Distinguisher data is determined that indicates if a node in the first collection can reach the first edge node without… Show more

Techniques for detecting loops in routes that cross route information boundaries include receiving a control message at a first edge node on one side of the boundary that is connected to a different second edge node on another side of the boundary. The control message indicates a particular network address of a particular node that is reachable from the first edge node. Distinguisher data is determined that indicates if a node in the first collection can reach the first edge node without leaving the first collection. An advertising message is sent from the first edge node to the second edge node that includes route data that indicates the particular network address and the distinguisher data. Based on the distinguisher data, a testing edge node in the first collection can determine whether there is a loop comprising both an internal path and an external path to the first edge node. Show less

In one embodiment, a border node receives a message that includes routing information indicating connection of a network device to a domain. The border node then updates a routing database with the routing information, and also uses a network address for the network device to determine whether to propagate the routing information.

An apparatus for communicating packets in a network environment is provided that includes a first network element that includes a first neighbor list, the first network element being coupled to a second network element and a third network element. The first network element is operable to receive a second neighbor list from the second network element and a third neighbor list from the third network element. The first network element is further operable to determine one or more overlaps provided… Show more

An apparatus for communicating packets in a network environment is provided that includes a first network element that includes a first neighbor list, the first network element being coupled to a second network element and a third network element. The first network element is operable to receive a second neighbor list from the second network element and a third neighbor list from the third network element. The first network element is further operable to determine one or more overlaps provided by the second and third neighbor lists when compared to the first neighbor list, the first network element relaying an update that it receives based on the one or more overlaps. Show less

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… Show more

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. Show less

In one embodiment, information is signaled between aggregating routers indicating the components of aggregated addresses. This information is used to dynamically leak, or deaggregate, specific parts of the aggregated address space to reduce sub-optimal routing and possibly prevent routing black holes from occurring in a network.

In one embodiment, a method includes receiving a first link state initiation (HELLO) message from a first neighboring router. The HELLO message requests that a recipient node send a unique identifier for itself in a link state routing protocol. In response to receiving the first HELLO message, a first response message is sent that includes a first identifier from an identifier pool. The identifier pool contains for a local node a plurality of network identifiers that are unique among all nodes… Show more

In one embodiment, a method includes receiving a first link state initiation (HELLO) message from a first neighboring router. The HELLO message requests that a recipient node send a unique identifier for itself in a link state routing protocol. In response to receiving the first HELLO message, a first response message is sent that includes a first identifier from an identifier pool. The identifier pool contains for a local node a plurality of network identifiers that are unique among all nodes in the network that uses the link state routing protocol. A second HELLO message is received from a different second neighboring router. In response to receiving the second HELLO message, a second response message is sent that includes a different second identifier from the identifier pool. Show less

In one embodiment, a method includes receiving authenticated site data that includes site ID data and address data. The site ID data indicates a unique site ID for each site among multiple sites for a first network that uses an internal routing protocol. Multiple edge sites of those sites are separate from each other and connected to a second network that is under separate administrative control of at least one different party. The address data indicates network addresses associated with each… Show more

In one embodiment, a method includes receiving authenticated site data that includes site ID data and address data. The site ID data indicates a unique site ID for each site among multiple sites for a first network that uses an internal routing protocol. Multiple edge sites of those sites are separate from each other and connected to a second network that is under separate administrative control of at least one different party. The address data indicates network addresses associated with each site of the plurality of sites. An external routing protocol message is discounted based on the authenticated site data. Show less

Each mobile router in a mobile ad hoc network is configured for identifying routes to nearby nodes that are within a prescribed distance, based on storage of explicit paths specified within routing headers of packets transmitted from a host node to a destination node. Each mobile router also can selectively compress the routing header, based on the storage of the explicit path, resulting in a loose source route type routing header in the packet output from the mobile router. In addition, a… Show more

Each mobile router in a mobile ad hoc network is configured for identifying routes to nearby nodes that are within a prescribed distance, based on storage of explicit paths specified within routing headers of packets transmitted from a host node to a destination node. Each mobile router also can selectively compress the routing header, based on the storage of the explicit path, resulting in a loose source route type routing header in the packet output from the mobile router. In addition, a routing header of a received packet can be expanded based on the mobile router inserting the explicit path, enabling mobile hosts in the explicit path to forward the packet according to strict source routing. The storage and compression of explicit paths also can be applied to packets specifying reverse routing headers, minimizing the size of the reverse routing headers. Show less

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… Show more

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. Show less

In one embodiment, a method includes receiving topology data that indicates multiple communication links and multiple intermediate network nodes in communication based on the communication links. The intermediate network nodes include multiple leaf nodes that terminate communications and multiple transit nodes that facilitate the passage of information between leaf nodes. Aggregation point data is also received, which indicates all aggregation points on the intermediate network nodes. An… Show more

In one embodiment, a method includes receiving topology data that indicates multiple communication links and multiple intermediate network nodes in communication based on the communication links. The intermediate network nodes include multiple leaf nodes that terminate communications and multiple transit nodes that facilitate the passage of information between leaf nodes. Aggregation point data is also received, which indicates all aggregation points on the intermediate network nodes. An aggregation point is an interface between a network node and a communication link, through which is output data that is a combination of data received through multiple different interfaces upstream of the interface. A set of paths is determined for which each path in the set connects a different pair of leaf nodes. A measure of aggregation is determined based on a number of aggregated paths of the set of paths. An aggregated path passes through an aggregation point. Show less

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… Show more

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. Show less

An example embodiment of the present invention provides a process relating to the selective filtering of an LSA at a not-so-stubby-sub-area (NSSSA) border router. In one embodiment, the border router receives an LSA from another router inside the NSSSA, which might be in the access layer of the hierarchical network design model and which might use OSPF as its IGP. If the LSA is Type 1 and includes a subnet route or forwarder address, the border router floods it to its neighboring routers… Show more

An example embodiment of the present invention provides a process relating to the selective filtering of an LSA at a not-so-stubby-sub-area (NSSSA) border router. In one embodiment, the border router receives an LSA from another router inside the NSSSA, which might be in the access layer of the hierarchical network design model and which might use OSPF as its IGP. If the LSA is Type 1 and includes a subnet route or forwarder address, the border router floods it to its neighboring routers, regardless of whether they are inside the NSSSA. If the LSA is Type 7 and includes a host address, the border router floods it to a neighboring router if the neighboring router is inside the NSSSA, but filters the LSA if the neighboring router is outside the NSSSA, for example, in an OSPF area in the distribution layer of the hierarchical network design model. Show less

Each mobile ad hoc node has an assigned hierarchy position within an identified tree-based aggregation group. Each ad hoc node is configured for selectively attaching to one of a plurality of available ad hoc nodes based on identifying a best match, for the assigned hierarchy position within the identified aggregation group, from among identifiable hierarchy positions of identifiable aggregation groups. Each ad hoc node also is configured for selectively attaching to any available ad hoc node… Show more

Each mobile ad hoc node has an assigned hierarchy position within an identified tree-based aggregation group. Each ad hoc node is configured for selectively attaching to one of a plurality of available ad hoc nodes based on identifying a best match, for the assigned hierarchy position within the identified aggregation group, from among identifiable hierarchy positions of identifiable aggregation groups. Each ad hoc node also is configured for selectively attaching to any available ad hoc node based on a determined absence of any available ad hoc node advertising the identified aggregation group of the ad hoc node, or an aggregation group containing the identified aggregation group. Hence, a root node of an aggregation group can filter group-specific routing information from packets destined toward a network clusterhead, resulting in a scalable routing protocol that is not adversely affected by added nodes. Show less

A method for verifying a validity of a path is provided that includes receiving an advertisement communication at a first autonomous system from a second autonomous system, the advertisement communication including a list of one or more connected autonomous systems. The method also includes identifying whether the first autonomous system claims a connection to the second autonomous system and whether the second autonomous system claims a connection to the first autonomous system such that… Show more

A method for verifying a validity of a path is provided that includes receiving an advertisement communication at a first autonomous system from a second autonomous system, the advertisement communication including a list of one or more connected autonomous systems. The method also includes identifying whether the first autonomous system claims a connection to the second autonomous system and whether the second autonomous system claims a connection to the first autonomous system such that two-way connectivity is established between the autonomous systems. In response to the establishment of the two-way connectivity, a directed graph is constructed that includes two nodes representing the first and second autonomous systems respectively. An edge may be formed that connects the two nodes. Show less

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… Show more

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. Show less

Techniques for sharing routing information over a network include determining whether the scale of a flooding domain exceeds a threshold. If so, then a router announcement message is sent over a particular link. The message indicates the local router is a flooding domain border router (FDBR). Summary routing information is determined with less than a certain level of detail used in the flooding domain for routers connected to the local router through links different from the particular link… Show more

Techniques for sharing routing information over a network include determining whether the scale of a flooding domain exceeds a threshold. If so, then a router announcement message is sent over a particular link. The message indicates the local router is a flooding domain border router (FDBR). Summary routing information is determined with less than a certain level of detail used in the flooding domain for routers connected to the local router through links different from the particular link. The summary routing information is sent over the particular link in a link state message that includes type data that indicates summary routing information that crosses a FDBR. These techniques allow automatic favorable scaling of domains of shared routing information as the size of a mobile ad hoc network grows. Show less

A method of processing both two-octet and four-octet autonomous system (AS) identifier values in a first network node that communicates with peer network nodes using Border Gateway Protocol (BGP), comprises receiving a first route message from a BGP peer node that is outside a local autonomous system that includes the first network node, wherein the BGP peer node can process only two-octet AS identifier values; identifying one or more extended community attributes in a route in the received… Show more

A method of processing both two-octet and four-octet autonomous system (AS) identifier values in a first network node that communicates with peer network nodes using Border Gateway Protocol (BGP), comprises receiving a first route message from a BGP peer node that is outside a local autonomous system that includes the first network node, wherein the BGP peer node can process only two-octet AS identifier values; identifying one or more extended community attributes in a route in the received route update message; for each of the identified extended community attributes, modifying the received route by creating an AS set containing four-octet AS identifier values carried in the identified extended community attributes, and attaching the AS set to the received route; and sending the modified received route to a third BGP node. Show less

Techniques for implementing forwarding in network devices are provided. Proxy addresses are used in place of next hop addresses so that a large routing table is not required. Pairs of proxy IP and MAC addresses can be used to allow this optimization to occur completely transparent to any other device in the network. One or more smaller tables can be utilized in place of a large routing table to more efficiently implement forwarding. Additionally, the technique can be utilized without requiring… Show more

Techniques for implementing forwarding in network devices are provided. Proxy addresses are used in place of next hop addresses so that a large routing table is not required. Pairs of proxy IP and MAC addresses can be used to allow this optimization to occur completely transparent to any other device in the network. One or more smaller tables can be utilized in place of a large routing table to more efficiently implement forwarding. Additionally, the technique can be utilized without requiring modification of other hardware devices in the network. Show less

A method and apparatus are presented supporting shortest path first (SPF) routing of data packets over a network by establishing link-state data at an router. Link-state data indicates direct links between the router and a different router and establishes an adjacency relationship with the different node. Initial link-state data is stored at a first router. After the initial link-state data is stored, a hello message is received at the first router. The hello message indicates a direct… Show more

A method and apparatus are presented supporting shortest path first (SPF) routing of data packets over a network by establishing link-state data at an router. Link-state data indicates direct links between the router and a different router and establishes an adjacency relationship with the different node. Initial link-state data is stored at a first router. After the initial link-state data is stored, a hello message is received at the first router. The hello message indicates a direct connection with a different second router on one network segment. Based on the initial link-state data, it is determined whether establishing an adjacency relationship with the second router is sufficiently valuable. If not, then an adjacency relationship is not established with the second router in response to the hello message. A shortest path first routing for a data packet traversing the network is determined based on one or more adjacency relationships indicated in link-state data stored at the first router. Show less

A method for communicating packets in a network environment is provided that includes communicating, by a first network element, a first summary update to a second network element. The method further includes receiving a second summary update from the second network element. The exchange of the first and second summary updates achieves adjacency between the first and second network elements. The first and second summary updates include, at least, locally generated state information and a single… Show more

A method for communicating packets in a network environment is provided that includes communicating, by a first network element, a first summary update to a second network element. The method further includes receiving a second summary update from the second network element. The exchange of the first and second summary updates achieves adjacency between the first and second network elements. The first and second summary updates include, at least, locally generated state information and a single link state. Show less

A method for reducing information being transmitted in a network is provided that includes gleaning routing information being communicated by a first network element, the routing information being stored such that the routing information may be accessed. An adjacency protocol may be executed between the first network element and a second network element that allows for a data exchange between the first and second network elements. The first network element does not communicate the routing… Show more

A method for reducing information being transmitted in a network is provided that includes gleaning routing information being communicated by a first network element, the routing information being stored such that the routing information may be accessed. An adjacency protocol may be executed between the first network element and a second network element that allows for a data exchange between the first and second network elements. The first network element does not communicate the routing information gleaned by the second network element during the data exchange associated with the adjacency protocol. Show less

An apparatus for communicating packets in a network environment is provided that includes a first network element that includes a first neighbor list, the first network element being coupled to a second network element and a third network element. The first network element is operable to receive a second neighbor list from the second network element and a third neighbor list from the third network element. The first network element is further operable to determine one or more overlaps provided… Show more

An apparatus for communicating packets in a network environment is provided that includes a first network element that includes a first neighbor list, the first network element being coupled to a second network element and a third network element. The first network element is operable to receive a second neighbor list from the second network element and a third neighbor list from the third network element. The first network element is further operable to determine one or more overlaps provided by the second and third neighbor lists when compared to the first neighbor list, the first network element relaying an update that it receives based on the one or more overlaps. Show less

A method and apparatus are presented for determining network nodes for aggregating addresses in routing information used for routing data packets over a network. Link data and reachability data are received. Link data indicates direct links between each of multiple candidate routers of a network and a different router or a network segment. Reachability data indicates a set of one or more contiguous network addresses that can be reached on each link described in the link data. A measure of… Show more

A method and apparatus are presented for determining network nodes for aggregating addresses in routing information used for routing data packets over a network. Link data and reachability data are received. Link data indicates direct links between each of multiple candidate routers of a network and a different router or a network segment. Reachability data indicates a set of one or more contiguous network addresses that can be reached on each link described in the link data. A measure of possible aggregation of contiguous network addresses is determined at the candidate routers based on the link data and the reachability data. A preferred router to aggregate addresses in routing information sent between routers in the network is determined among the candidate routers based on the measure of possible aggregation at each candidate router. Show less

A method for communicating packets in a network environment is provided that includes receiving a packet at a network element and identifying a sequence number included in the packet that correlates to awareness information associated with one or more adjacent network elements. A table included in the network element may be updated in order to account for the awareness information included within the packet that has not been accounted for by the network element. In cases where the awareness… Show more

A method for communicating packets in a network environment is provided that includes receiving a packet at a network element and identifying a sequence number included in the packet that correlates to awareness information associated with one or more adjacent network elements. A table included in the network element may be updated in order to account for the awareness information included within the packet that has not been accounted for by the network element. In cases where the awareness information included in the packet has already been accounted for, the packet may be ignored. Show less