Cisco Technology, Inc.

Claude Alan Cartee

Kenneth A Moberg

Andrew J Valencia

William B May, Jr

Kirk Stewart Lougheed

Pedro Marques

Gregory D Stovall

David R Hampton

Timothy D Kolar

Pradeep Kumar Kathail

Chandrashekhar Appanna

Kenneth Harvey Potter, Jr

Frederick Juergens Baker

Manoj Leelanivas

Bernie P Pearce

Zhanhe Shi

Randall Graham Campbell

Jeffrey Wayne Kidd

Kara J Adams

David A Carroll

Carson Stuart

Kevin R Lingle

Eric Decker

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.

Packet processing using encapsulation and decapsulation chains

The invention solves the problem of maintaining Route information Field (RIF) information in a router for populating the RIF field of packets routed by the router, by storing the RIF information with the Layer 2 address in the address binding table. The address binding table establishes a binding between a Layer 2 address and a Layer 3 address of a station. The Layer 2 address in the address binding table is extended to include the RIF information. The address binding table is normally maintained in the router in an architecture which permits rapid access for fast switching such as cut through routing. A separate RIF cache table, requiring a separate time consuming table look-up is thereby avoided. The address binding table is referred to as the Address Resolution Protocol (ARP) Table in IP protocol. The Layer 2 address is extended to include both MAC address and REF information. The RIF information in the Layer 2 field of the ARP table is updated in response to execution of an ARP Explorer protocol by the router. RIF information is read from an ARP Explorer response packet and written into the Layer 2 field of the ARP table. The Layer 2 address, both MAC address and RIF information, is read from the ARP table for use in populating both the destination address field and the RIF field of a routed packet.

MAC address extension to maintain router information in source routed computer networks

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.

Dynamically building encapsulation and decapsulation chains at run time

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. Decapsulation and encapsulation chains can be built dynamically, by inserting new and removing old elements as necessary as new protocols are developed and new features added. A chain walker walks through the chains, passing the processed packet to each element in a chain, until either the end of the chain is reached and processing is complete, or until the packet is dropped because no function can process it, or because a packet is processed by an outside process or by hardware, which may optionally stop the chain walk. A chain walk may be temporarily halted, or may be terminated. If temporarily halted, the chain walk can be resumed at any element in the chain, depending on the packet's requirements. A chain walk can also begin at any element in a chain.

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.

Congestion management system and method

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. Decapsulation and encapsulation chains can be built dynamically, by inserting new and removing old elements as necessary as new protocols are developed and new features added. A chain walker walks through the chains, passing the processed packet to each element in a chain, until either the end of the chain is reached and processing is complete, or until the packet is dropped because no function can process it, or because a packet is processed by an outside process or by hardware, which may optionally stop the chain walk. A chain walk may be temporarily halted, or may be terminated. If temporarily halted, the chain walk can be resumed at any element in the chain, depending on the packet's requirements. A chain walk can also begin at any element in a chain. Alternate branches within the chain can be provided, where each branch can comprise zero or more elements. A classifier determines which branch to take, based on at least one characteristic of the packet being processed, and executes the elements of the selected branch.

Packet processing using non-sequential encapsulation and decapsulation chains

A distributed token ring (TR) bridge has a logical switch fabric that is distributed over a TR switching network of switches interconnected by trunk links. The distributed TR bridge includes a plurality of TR switches, each having a Bridge Relay Function (BRF) logically coupled to at least one Concentrator Relay Function (CRF). Distribution of the switch fabric essentially comprises logically distributing the BRF function among the network of switches.

Token ring bridge distributed in a switched fabric

Growing community of inventors

Los Altos, CA, United States of America

Claude Alan Cartee