128 Technology, Inc.

Juniper Networks, Inc.

Sarah V Jaffer

Patrick John MeLampy

Michael Baj

Patrick Timmons

Abilash Menon

Kaushik Adesh Agrawal

Michael John Adams

Ryan Koss

Anna Yungelson

A first router generates session establishment metrics for use in network path selection. For example, a plurality of routers connect a client device to a network service instance hosted by a server. A first router is connected to the network service instance via first and second paths. The first router receives session performance requirements for a session between the client device and the network service instance. The first router forwards, along the first path, network traffic for the session by modifying a first packet of the session to include a session identifier for the session. The first router determines that session establishment metrics for the session do not satisfy the session performance requirements. In response, the first router forwards, along the second path, the network traffic for the session by modifying a second packet of the session to include the session identifier for the session.

Session monitoring using metrics of session establishment

A method and apparatus for routing a plurality of session packets across a network toward a destination modifies each packet to include a sequence number that is different from the sequence number of other packets in the plurality of packets. Accordingly, at this point, each of the plurality of packets is transformed into a corresponding plurality of processed packets. The method also duplicates the plurality of processed packets to produce a corresponding plurality of duplicated packets. Next, the method forwards the plurality of processed packets toward the destination using a first stateful path through the network, and correspondingly forwards the plurality of duplicated packets toward the destination using a second stateful path through the network. In preferred embodiments, the first stateful path is different from the second stateful path. For example, the two paths may be entirely distinct in that they share no common intermediary elements.

Router device using flow duplication

A router is specially configured to implement a bilateral TCP state machine to monitor the status of TCP sessions based on TCP sequence numbers in both forward session packets and return session packets received by the router for a TCP bi-flow session. Among other things, the router may determine the status of a TCP session, for example, based on statistical information such as the number or rate of errors detected (e.g., the number of dropped packets, duplicated packets, out-of-sequence packets, and/or out-of-window packets). Each router is typically configured to collect and store status information and optionally also to use the status information in making intelligent routing decisions, such as, for example, deciding whether or not to forward a particular packet, deciding whether to reconfigure a bi-flow routing session, or updating routing table information used for routing packets.

Router with bilateral TCP session monitoring

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Billerica, MA, United States of America

Sarah V Jaffer