Cisco Technology, Inc.

Ruchi D Kapoor

Chandrashekhar Appanna

Keyur Patel

Anantha Ramaiah

Gargi Nalawade

Mitesh Dalal

James Neil Guichard

John Harper

Himanshu H Shah

Robert Raszuk

Lester Bird

Arjun Sreekantiah

Barry Friedman

Rakesh Dubey

Shyam Suri

Siva Yaragalla

Angelo D Calabrese

Charles I Goldberg

Kevur Patel

A method for detecting unavailable network connections comprises, at a first data processing node that is hosting a transport protocol connection that uses a plurality of sequence values to identify messages sent to a peer node, wherein the first node is communicatively coupled to a second data processing node serving as a redundant backup, periodically sending a checkpoint sequence value to the second node; detecting that either the transport protocol connection or a process using the transport protocol connection is unavailable, without use of a timeout; and in response thereto, sending a notification to the peer node, wherein the notification includes the checkpoint sequence value. One embodiment provides for rapidly detecting and responding to failure of a TCP process without using long timeouts as conventionally provided in long-lived applications that run on top of TCP.

Detecting unavailable network connections

A method and apparatus is disclosed for graceful restart in a multi-process operating system. A transport protocol process, which is capable of restarting independently from the operating system, is executed in a network element. The network element executes a Border Gateway Protocol (BGP) process, which installs one or more routes in a global Routing Information Base (RIB). When the BGP process detects that the transport protocol process has become unavailable, the BGP process keeps the one or more routes in the global RIB even though the transport protocol process is not available.

Techniques for graceful restart in a multi-process operating system

A network data packet routing apparatus with BGP is configured to soft reset an AFI or SAFI, so that forwarding on routes associated with the AFI or SAFI can continue even after an event or error. One approach involves establishing a Border Gateway Protocol (BGP) peering session between a first node and a second node in a packet-switched network; detecting a BGP condition requiring a reset of a BGP address family indicator (AFI) data structure or a sub-address family indicator (SAFI) data structure, wherein the BGP condition does not affect states of routes in the AFI or SAFI; preserving a BGP state and a forwarding state of the AFI or SAFI; and forwarding data on routes represented in the AFI or SAFI. Soft notification messaging and marking routes as stale facilitates the approach.

Network routing apparatus that performs soft graceful restart

A method is disclosed for rapidly detecting a protocol failure. In one embodiment, the method includes receiving an indication that a first process has failed. The first process having been engaged in communications over one or more network connections with a second process. A packet is formed, such that the packet appears to have been formed by the first process. The packet includes one or more data values, which, when received and processed by the second process, will cause the second process to close the network connection. The packet is sent to the second process. When the second process receives the packet, the second process to closes the network connection.

Rapid protocol failure detection

A method for scaling hierarchical route reflectors (RRs) using automated Outbound Route Filtering (ORF) is presented. A first route reflector identifies other route reflectors configured as Route reflector clients within a route reflector hierarchy. The first route reflector then builds a common set of route target filters received from the client route reflectors and sends the common set of route target filters to client route reflectors.

Method to scale hierarchical route reflectors using automated outbound route filtering-list mechanism

Methods and apparatus for efficiently enabling routing states to be recovered after a failover or during a software upgrade in a system which supports graceful restart and stateful switchover are disclosed. According to one aspect of the present invention, a method for restarting a network device which has a plurality of routers and is in communication with a first peer being arranged to support graceful restart and a second peer includes performing a graceful restart with respect to the first peer. A peer transparent failover is performed with respect to the second peer. The graceful restart and the peer transparent failover are performed in response to a failure associated with the network device.

Routing system and method for transparently rocovering routing states after a failover or during a software upgrade

A method is disclosed for providing prioritized routing table convergence in Border Gateway Protocol (BGP) hosts, as part of a BGP process that is executed by a route processor in a network, wherein the processor hosts a plurality of BGP routing tables each associated with a specified sub-address family (SAFI). A convergence priority order value is created and stored in association with each routing table. As part of performing a convergence phase of BGP processing, the convergence priority order value of each routing table is obtained. The convergence phase is then performed for the routing tables only according to an order that is represented by the convergence priority order values. Therefore, convergence proceeds more quickly and values needed by other routing processes become available earlier.

Method and apparatus providing prioritized convergence in border gateway protocol

A new network traffic data collection technique is presented. A group of information is received, and a determination is made whether to process the group of information for network data collection according to a sample mode and a sample rate. If the determination is to process the group of information, the group of information is processed for network data collection. The group of information is forwarded according to its destination address. The group of information can be an IP packet and the sample mode can be, for example, one of linear, exponential, natural log, burst and traffic attribute. To process the group of information, a determination is made whether the group of information is part of one or more recorded traffic flows. If not, a new entry in a table is created. If so, a field in an existing entry in the table is incremented. In addition, a traffic information packet is created and transmitted to a network traffic data collection application. The traffic information packet can consist of a header and one or more flow records.

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Sunnyvale, CA, United States of America

Ruchi D Kapoor