Abstract: A blade switch for increased interface scalability is provided. The blade switch may address interface scalability by having each of the switch linecards manage its interfaces locally and may use the concept of virtual and local interfaces for intelligent forwarding. The blade switch may appear as a single network switch having a single bridge ID from the network perspective during operation and from the customer perspective during configuration.

Abstract: A system and method supporting efficient, scalable stateful switchover of transport layer connections in a telecommunications network element. One method involves receiving, at a network element comprising an active transport protocol process coupled to a standby protocol process, a request to configure a first transport layer connection maintained at the active transport protocol process for stateful switchover; receiving an event associated with the first transport layer connection; creating a message containing replicated event information based on the received event; sending the message to the standby transport protocol process; and processing the message at the standby transport protocol process, wherein the standby transport protocol process replicates state information for the first connection.

Abstract: In one embodiment, a method includes receiving, by a first autonomous system border router (ASBR) of a first autonomous system (AS), a first plurality of provider-provisioned media access control (B-MAC) addresses via Interior Border Gateway Protocol (I-BGP). Each of first plurality of B-MAC addresses is associated with a provider edge (PE) device of the first AS. The first ASBR sends the first plurality of B-MAC addresses to a second ASBR of a second AS using Exterior Border Gateway Protocol (E-BGP). The first ASBR also receives via E-BGP a second plurality of B-MAC addresses each of which is associated with a PE device of the second AS. The first ASBR then distributes the second plurality of B-MAC addresses to each of the PE devices of the first AS using I-BGP.

Abstract: A checkpointing approach enables BGP peers to reduce the number of UPDATE messages that are exchanged and processed after a router restarts. A router receives update messages to update routing information for the one or more other devices, wherein each of the update messages includes a checkpoint marker and a route. The router stores the route in a checkpoint repository and stores the checkpoint markers in association with information identifying the other routers from which the checkpoint markers were received. In response to a restart event, the router sends each of the stored checkpoint markers to respective other devices and receives from the respective other devices only route updates that occurred later in time than the checkpoint markers.

Abstract: 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.

Abstract: A checkpointing approach enables BGP peers to reduce the number of UPDATE messages that are exchanged and processed after a router restarts and to pause and suspend BGP sessions when mobile nodes leave a BGP domain. In an embodiment, a router is configured for receiving a BGP pause message from a mobile node; suspending interaction with the mobile node using BGP, including suspension of expiration of BGP sessions for lack of keepalive messages; receiving a BGP resume message from the mobile node, wherein the resume message comprises a checkpoint marker that identifies a last route update that the mobile node received before the suspending; resuming interaction with the mobile node using BGP; and determining and sending to the mobile node all BGP routes that originated after the checkpoint marker.

Abstract: Approaches are disclosed for switching transport protocol connection keys. A method of automatically changing a message authentication key at each of two endpoints of a connection in a telecommunications network comprises testing a date-time value received in each of a plurality of data segments on the connection; and selecting a next message authentication key, from among a plurality of stored message authentication keys, for use in authenticating subsequently received data segments, when the date-time value matches a specified characteristic.

Abstract: A system and method for performing stateful switchover with reduced data, such as only metadata about a TCP window state. The metadata comprises a size of TCP packets used to send BGP messages, and which of those have been acknowledged by a neighbor networking device. The networking device comprises a BGP module to establish a BGP session between the networking device and a neighbor networking device. An active transport module within the networking device synchronizes with a standby transport module within the networking device by sending the metadata. A fault detector within the networking device initiates a stateful switchover from the active transport module to the standby transport module responsive to detecting a failure of a process and/or processor. The standby transport module uses the metadata to determine stateful metadata for preserving current BGP and TCP sessions of the networking device.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A system and method supporting efficient, scalable stateful switchover of transport layer connections in a telecommunications network element. One method involves receiving, at a network element comprising an active transport protocol process coupled to a standby protocol process, a request to configure a first transport layer connection maintained at the active transport protocol process for stateful switchover; receiving an event associated with the first transport layer connection; creating a message containing replicated event information based on the received event; sending the message to the standby transport protocol process; and processing the message at the standby transport protocol process, wherein the standby transport protocol process replicates state information for the first connection.

Abstract: A system and method supporting synchronization of replicated transport layer connections in a redundant processor telecommunications network element. One method involves receiving, at a network element comprising an active transport protocol process coupled to a standby transport protocol process, information identifying a newly created transport layer connection maintained at the active transport protocol process; assigning a unique connection identifier to the transport layer connection; sending the unique connection identifier, in association with other, protocol-specific connection identifying information, to the standby protocol process; and sending, to the standby transport protocol process, one or more messages comprising one or more properties or statistics associated with the transport layer connection, wherein the messages identify the transport layer connection using the unique connection identifier.

Abstract: A system and method supporting efficient, scalable stateful switchover of transport layer connections in a telecommunications network element. One method involves receiving, at a network element comprising an active transport protocol process coupled to a standby protocol process, a request to configure a first transport layer connection maintained at the active transport protocol process for stateful switchover; receiving an event associated with the first transport layer connection; creating a message containing replicated event information based on the received event; sending the message to the standby transport protocol process; and processing the message at the standby transport protocol process, wherein the standby transport protocol process replicates state information for the first connection.

Abstract: Approaches are disclosed for switching transport protocol connection keys. A first node sends a keychange request message to a second node, causing the second node to accept subsequent messages digitally signed with a first or second key. The second node sends an acknowledgment message to the first node, causing the first node to accept subsequent messages digitally signed with the first or second key. The first node receives a new message digitally signed with the second key from the second node and determines that there are no remaining messages to be received digitally signed with the first key. In response thereto, the first node only accepts messages digitally signed with the second key and sends a message signed with the second key to the second node, causing the second node to only accept messages digitally signed with the second key.

Abstract: A method of improving convergence in networks that use path vector protocols. In one embodiment using Border Gateway Protocol (BGP) for inter-domain route and reachability communication, nodes that need to remove routes using EBGP NLRI announcements send BGP WITHDRAW messages containing a new route originator attribute that identifies an originator of a specified withdrawn route. A receiving node removes the specified route from its routing information base (RIB), and matches the originator to other paths in the RIB. Matching paths are marked as ineligible for consideration in a best path computation, thereby preventing the use of routes that are unreachable but not yet withdrawn by an originating node. The approach causes faster BGP convergence, reduces unnecessary route flapping, and alleviates unnecessary route dampening.

Abstract: A method of improving BGP convergence in a packet-switched network comprises receiving, at a router in the packet-switched network, an advertisement of a first route that includes alternate route information indicating that an alternate route is available; storing the alternate route information in association with the first route; detecting a change in network reachability of the first route, and in response thereto, determining if the alternate route information is stored for the first route, and if so: awaiting, for a particular time, an advertisement of an alternate route; storing and using the alternate route in place of the first route.

Abstract: 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.

Abstract: A method detects a change in TCP receive window size while preventing fragmentation of data. A TCP stack receives a segment that advertises a receive window size of zero. If data needs to be sent, and only if so, a timer is started. When the timer expires, a TCP segment that contains a first sequence number value equal to second sequence number representing sent but unacknowledged data minus one, and a segment length value of zero, is sent. Without sending a fragment of data, this triggers a peer TCP process to send an updated window size. A TCP ACK segment is received and contains an updated receive window size. If the updated receive window size is greater than a specified value, then the data is sent. Otherwise, a counter is incremented, and the steps are re-performed if the counter is less than a specified value.

Abstract: A method is disclosed for upgrading network protocol software, comprising receiving a new version of Border Gateway Protocol (BGP) software on a standby route processor that is coupled to an active route processor in a redundant arrangement; transferring, from the active route processor to the standby route processor, one or more transport protocol connections that are associated with one or more active BGP sessions of the active route processor; transferring, from the active route processor to the standby route processor, BGP session information representing the active BGP sessions; progressively shutting down an active BGP process of the active route processor; and switching control of BGP data processing to the standby route processor. The route processors may be placed in a stateful switchover mode of operation temporarily only during the transferring, shutting down, and switching. Thus a hitless BGP upgrade approach is provided.