Abstract: In an embodiment, a network router includes plural interfaces and a chain walker which, upon receipt of a first protocol packet in a first interface, processes the packet by walking the packet through a decapsulation chain associated with the interface and the first protocol and an encapsulation chain associated with an identified second interface and identified second protocol. The walker passes the packet to elements of the decapsulation chain to produce a decapsulated packet. The walker passes the decapsulated packet to elements of an encapsulation chain to produce an encapsulated packet. Each chain includes at least one packet-processing element. An element receives the packet from the walker as processed by a previous element, the packet being further processed as appropriate. The walker, upon receipt of the first protocol packet, passes the packet to elements of a demultiplexer chain associated with the first interface to produce a demultiplexed packet.

Abstract: A method for dynamically building a packet processing chain includes providing a plurality of packet processing elements. For each element of a first subset of elements operations indications are provided. For each element of a second subset of elements, expectations indications are provided. Finally, the chain is built by combining elements to form the chain according to a configuration requirement. Elements are selected such that an element's indicated expectations are satisfied by the time it executes, as indicated by the operations indications of the previous chain element.

Abstract: A method for processing packets in a router includes specifying operations on packets as chains of processing elements. Each chain is uniquely associated with one interface/protocol pair, and each processing element performs at least one function on a packet. An incoming packet is received, and processed, first by a demultiplexor element which determines the protocol of the next higher level used by the packet. Then, the packet is processed by the elements of a decapsulation chain associated with the interface on which the packet was received, and by the elements of an encapsulation chain associated with the interface on which the packet is to be transmitted. The demultiplexor element or operation passes the packet on to a decapsulation chain associated with the protocol and with the incoming interface, depending on protocol information contained in the incoming packet.

Abstract: A method of monitoring congestion within a data path having a queuing node located therein and a plurality of downstream nodes positioned downstream of the queuing node. The method includes monitoring congestion at the plurality of downstream nodes and setting a congestion notification flag by one of the downstream nodes when the node is congested. The transmission of data packets from the queuing node is stopped and packets received at the queuing node are queued when the flag is set. The method further includes transmitting packets from the queuing node when the congestion notification flag is cleared. A system for monitoring congestion on a data path is also disclosed.

Abstract: A method for processing packets in a router includes specifying operations on packets as chains of processing elements. Each chain is uniquely associated with one interface/protocol pair, and each processing element performs at least one function on a packet. An incoming packet is received, and processed, first by a demultiplexor element which determines the protocol of the next higher level used by the packet. Then, the packet is processed by the elements of a decapsulation chain associated with the interface on which the packet was received, and by the elements of an encapsulation chain associated with the interface on which the packet is to be transmitted. The demultiplexor element or operation passes the packet on to a decapsulation chain associated with the protocol and with the incoming interface, depending on protocol information contained in the incoming packet.