Cisco Technology, Inc.

Abhay Kumar Roy

Sina Mirtorabi

Alvaro E Retana

Alfred C Lindem, Iii

Yi Yang

Ayan Banerjee

Navindra Yadav

Suresh Katukam

Syed Khalid Raza

James L Ng

Timothy M Gage

Russell Ivan White

Raghava Kodigenahalli Sivaramu

Jean-Philippe Vasseur

Stefano Benedetto Previdi

Keyur Patel

Sanjay Sane

Dino Farinacci

Lester C Ginsberg

Nair Venugopal

Venkata Tanikella

Veena Raghavan

Pascal Thubert

Patrick Wetterwald

Brian Eliot Weis

Alpesh S Patel

Ronak K Desai

Shree N Murthy

Vincent Jean Ribiere

Chandrashekhar Appanna

Varun A Shah

Scott Roy Fluhrer

Robert Raszuk

Derek Man-Kit Yeung

Santosh Rajagopalan

Kui Zhang

Madhavi Wunnava Chandra

David Anthony Cook

Hariharan Balasubramanian

Praveen Joshi

Mukhtiar Shaikh

Syam Sundar Appala

Alexey Dimitrievich Zinin

Christian E Hopps

Liem Hong Nguyen

Yousuf Hasan

Rajeev Koripalli

Alfred Iii Lindem

Aspects of the embodiments are directed to synchronizing at least a portion of a link-state database. A network element can lose an adjacency. The network element can transmit a request to a neighboring network element for synchronization of a link-state database. The request can include a version number of a last synchronized link-state database from the neighboring network element. The neighboring network element can determine whether the version of the link-state database is greater than or less than a copy of the link-state database stored by the neighboring network element. If the requested version number is less than the neighboring network element's link-state database version number, then the neighboring network element can send changes to the link-state database since the requested link-state database version number.

Delta database synchronization

In one embodiment, a first router determines whether an interface coupling the first router to one or more second routers is transit-only. When the interface is transit-only, the first router generates an Open Shortest Path First (OSPF) Link State Advertisement (LSA) that includes an address for the interface and a designated network mask. The designated network mask operates as a transit-only identification that indicates the address should not be installed in a Routing Information Base (RIB) upon receipt of the OSPF LSA at the one or more second routers. When the network is not transit-only, the first router generates an OSPF LSA that includes the address for the interface but does not include the designated network mask, to permit installation of the address in a RIB upon receipt of the OSPF LSA at the one or more second routers.

Apparatus and method to hide transit only multi-access networks in OSPF

Techniques are provided for generating efficient flooding tree paths in a network. At a node device in a network, a unicast message is sent to a plurality of node devices in the network. The node device obtains an identifier associated with each of the node devices in the network. The identifier contains information indicating node connectivity for each of the node devices. A selected node device is then identified. The selected node device is one of the node devices in the network that has a lowest identifier value indicating a lowest number of connected node devices to the selected node device in the network. The selected node device is classified as a root flooding tree node device. A flooding tree is generated by performing a shortest path first operation from the selected node device to the plurality of node devices in the network.

Techniques for flooding optimization for link state protocols in a network topology

In one embodiment, a first router determines whether a network coupling the first router to one or more second routers is transit-only, wherein transit-only indicates connecting only routers to provide for transmission of data from router to router. When the network is transit-only, the first router generates an Open Shortest Path First (OSPF) Link State Advertisement (LSA) that includes an address for the network and a designated network mask. The designated network mast operates as a transit-only identification that indicates the address should not be installed in a Routing Information Base (RIB) upon receipt of the OSPF LSA at the one or more second routers. When the network is not transit-only, the first router generates an OSPF LSA that includes the address for the network but does not include the designated network mask, to permit installation of the address in a RIB upon receipt of the OSPF LSA at the one or more second routers.

In an example embodiment, a method is provided that assigns a sequence value to a host. The host is identified by a host network layer address. After the assignment, the host network layer address and the sequence value are included in an advertisement for transmission. In another example embodiment, another method is provided. Here, a first sequence value associated with the host network layer address is received from a network device. In addition, a second sequence value associated with the same host network layer address is received from a different network device. The first sequence value is ranked relative to the second sequence value and data is transmitted to the network device based on the ranking.

Host route convergence based on sequence values

Techniques to optimize root network node selection for network tree paths are provided. A network disruption event is detected. Network nodes in the network are configured with root priorities. Network nodes in a first set of the network nodes operate as root nodes for ordered network tree paths. Root priority information is retrieved from a database for each of the network nodes. Based on the root priority information, network nodes are selected for a new set of network nodes to operate as new root nodes for new ordered network tree paths upon occurrence of the network disruption event. The new set of network nodes comprises common network nodes present in the first set. An order of the network nodes in the new set is determined such that at least one common network node in the new set is maintained in the same order as that in the first set.

Optimizations in multi-destination tree calculations for layer 2 link state protocols

A method is provided in one example embodiment and includes receiving a first pseudo-node identifier associated with a first network node via a network. The first pseudo-node identifier is generated by the first network node in a first designated intermediate system (DIS) operation. The method further includes detecting a loss of connectivity to the first network node, and receiving a second pseudo-node identifier associated with a second network node via the network. The second pseudo-node identifier is generated by the second network node in a second DIS operation. The method further includes executing a first network path determination operation using the first pseudo-node identifier and the second pseudo-node identifier when an elapsed time between the detecting of the loss of connectivity with the first network node and the executing of the first network path determination operation is within a predetermined threshold.

System and method for maintaining connectivity in a single-hop network environment

A method is provided in one example embodiment and includes establishing a communication pathway between a first network node and a second network node coupled to a network; forming an adjacency to a new network node coupled to the network, where a designated intermediate system (DIS) election operation is executed after the adjacency is formed in order to determine that the new network node is a newly identified DIS for the network; and communicating a message advertising connectivity to both a previously identified DIS and the newly identified DIS, where the message is communicated during a specified time interval.

System and method for intelligently maintaining connectivity in a network environment

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.

Differentiated services for unicast and multicast frames in layer 2 topologies

In one embodiment, detecting a host device on a port of a forwarder switch in a network, detecting a movement of the host device from a first forwarder switch to a second forwarder switch, and multicast broadcasting an updated device information for the host device to a convergence group switches and a proximity group switches, where the convergence group switches includes switches in the network that are not configured as forwarder switches, and the proximity group switches include forwarder switches grouped together based on radio proximity is provided.

Host route convergence

In one embodiment, a Link State Advertisement (LSA) is received from a first router in a network at a second router in the network. The LSA advertises an address of an interface of the first router. The second router determines whether the LSA includes a transit-only identification that indicates the interface of the first router is a transit-only interface. If the LSA does not include a transit-only identification, the second router installs the advertised address of the interface of the first router in a Router Information Base (RIB) of the second router. If the LSA does include a transit-only identification, the second router declines to install the advertised address of the interface of the first router in the RIB of the second router.

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

Method and apparatus for sequencing operations for an incoming interface check in data center ethernet

In one embodiment, a method includes setting a re-flood time to a non-zero first value. Update data that indicates a change to link data is received over a network interface from an updating node of multiple nodes on a multi-access segment connected to the interface. The change is to link data that indicates links on the updating node. It is determined whether an acknowledgment message is not received within the re-flood time from a particular node of the multiple nodes. If an acknowledgment message is not received within the re-flood time, then a multicast packet directed to the multiple nodes and including the change to the link data is sent over onto the segment. This method enables rapid response to failure of a primary node designated to ensure reliable flooding of link data.

Sending routing protocol data on a multi-access network segment

In one example embodiment, a system and method are shown that includes calculating a first SPF tree for a first device, the first SPF tree including a root node and a first child node, the first device being the root node of the first SPF tree. Additionally, the system and method may include calculating a second SPF tree for a second device that is a neighbor of the first device, the second SPF tree including a root node and a first child node, the second device being the root node of the second SPF tree. Further, the system and method may include building a set of interested nodes including the second device, if the first child node if the first SPF tree and the first child node of the second SPF tree are distinct.

Link state protocol routing message containment

Growing community of inventors

San Jose, CA, United States of America

Abhay Kumar Roy