Cisco Technology, Inc.

Nortel Networks Corporation

Northern Telecom Limited

Mohammed Ismael Tatar

David Delano Ward

Garry Paul Epps

Cedrik K Begin

John Joseph Williams, Jr

Eyal Oren

Oded Trainin

Naader Hasani

Clarence Filsfils

Mark Stephen Wight

Alan Glen Solheim

John H W Bettink

Promode Nedungadi

Ronald Joseph Gagnon

Mark Andrew Gustlin

David Wright Martin

David John Nicholson

Sreedhar Ravipalli

Timothy James Armstrong

Steven Philip Holmes

David Richard Barach

Guy Fedorkow

David J Tsiang

John Bettink

Shishir Gupta

Gary Nicholl

Tim Webster

Shahin Habibi

David Doak

Randall A Johnson

Anna Charny

John William Marshall

Luca Della Chiesa

Matthew Hayden Harper

John C Carney

Michael E Lipman

Dipankar Bhatt Acharya

Stefano Binetti

Barry Scott Burns

Palani Chinnakannan

James Alexander Markevitch

Walid Wakim

John P Prokopik

David Getchell

Brian Lance Hiltscher

Adrian Evans

Michael J Taylor

Stephane Gagnon

Qian Zhang

Christopher Chan

Christopher Yates Satterlee

Theodore Kupfer

Peter J Barry

Ratan Ramchandani

Kalamaljit S Masonde

Jeffrey Nelson Shaw

John J Williams Jr

Barry S Burns

Brian Hiltscher

In one embodiment, a network node automatically cycles among packet traffic flows and subjects the currently selected packet flows to varying drop probabilities in a packet network, such as, but not limited to in response to congestion in a device or network. Packets of a currently selected packet traffic flow are subjected to a drop or forward decision with a higher drop probability than packets of a currently non-selected flow. By cycling through all of these packet traffic flows, all of these packet flows are subjected to the drop or forward decision in the long term approximately uniformly, thus providing fairness to all packet traffic flows. In the short term, packets of a currently selected flow are targeted for possible dropping with a higher drop probability providing unfairness to the currently selected flows over the non-selected flows.

Automatically cycling among packet traffic flows subjecting them to varying drop probabilities in a packet network

One embodiment performs longest prefix matching operations in one or more different manners that provides packet processing and/or memory efficiencies in the processing of packets. In one embodiment, a packet switching device determines a set of one or more mask lengths of a particular conforming entry of a multibit trie or other data structure that matches a particular address of a packet via a lookup operation in a mask length data structure. A conforming entry refers to an entry which has less than or equal to a maximum number of different prefix lengths, with this maximum number corresponding to the maximum number of prefix lengths which can be searched in parallel in the address space for a longest matching prefix by the implementing hardware. The packet switching device then performs corresponding hash table lookup operation(s) in parallel in determining an overall longest matching prefix for the particular address.

Longest prefix matching providing packet processing and/or memory efficiencies in processing of packets

In one embodiment, for each distribution period of time, each packet flow is assigned to a path through a packet switching device (e.g., switch fabric) with all packets of the packet flow being sent in order over the assigned path. For a next distribution period, different paths are assigned for these packet flows, with all packets being sent in order over the new corresponding selected path. In one embodiment, these paths are switched often enough to prevent congestion, yet infrequent enough so as to minimize resources for reordering. In one embodiment, the reordering is done at the egress and only for predefined high bandwidth flows (e.g., elephant flows). A distribution period indication is typically associated with each packet to identify its corresponding distribution period. In one embodiment, each routing and egress switching stage in a switching fabric performs reordering.

Packet switching device modifying paths of flows of packets taken within while outputting packets in received intra-flow order but not necessarily inter-flow order

In one embodiment, a network node automatically cycles among packet traffic flows and subjects the currently selected packet flows to varying drop probabilities in a packet network, such as, but not limited to in response to congestion in a device or network. Packets of the currently selected packet traffic flows are subjected to a drop or forward decision, while packets of other packet traffic flows are not. By cycling through all of these packet traffic flows, all of these packet flows are subjected to the drop or forward decision in the long term approximately uniformly providing fairness to all packet traffic flows. In the short term, only packets of a currently selected flow are targeted for possible dropping providing unfairness to the currently selected flows, while possibly providing communication efficiencies by affecting the currently selected, but not all flows.

One embodiment includes multiple distribution nodes sending packets of different ordered sets of packets among multiple packet switching devices arranged in a single stage topology to reach a reordering node. The reordering node receives these packets sent over the different paths and stores them in reordering storage, such as, but not limited to, in queues for each distribution node and packet switching device combination. The reordering node sends packets stored in the reordering storage from the reordering node in original orderings. In response to determining that an aggregation quantum of packets received from the multiple distribution nodes via a particular packet switching device and stored in the reordering storage is outside a range or value, packets being communicated via the particular packet switching device to the reordering node are rate limited.

Distributing and rate limiting packets among multiple paths in a single stage switching topology to a reordering node

One embodiment includes a packet switching device load balancing eligible packets in response to a policing drop decision. The packet switching device sends packets of a particular packet flow out of the packet switching device over a first path in the network towards a destination node; and in response to a policer discipline determining to drop a particular packet of the particular packet flow, switching from said sending packets over the first path to sending packets of the particular packet flow out of the packet switching device over a second path in the network towards the destination node (possibly by switching output queues associated with the two different paths), with the second path being different than the first path, and with the particular packet not being dropped but being sent out of the packet switching device towards the destination node.

Load balancing eligible packets in response to a policing drop decision

In one embodiment, multicast packets including, but not limited to, Bit Index Explicit Replication (BIER) multicast packets, are forwarded in a network. An independent lookup operation is performed on each destination node identified in the received packet to determine a nexthop to which to forward a copy of the packet. Typically, some or possibly all of these lookup operations are performed in parallel, in contrast to the sequential lookup and bit masking operations of previous BIER packet forwarding specifications and implementations. In one embodiment, the selection of a nexthop for a destination node is made from a set of two or more nexthop nodes on different Equal-Cost Multi-Paths (ECMPs). In one embodiment, compact data structures are used in determining how to forward the received multicast packet, with these compact data structures providing requisite forwarding information without allocating space to unassigned destination nodes.

Forwarding of multicast packets in a network

One embodiment is associated with dropping or admitting packets to an output queue using occupancy values of virtual destination queues which are updated according to different independent disciplines upon the enqueuing of a packet to an output queue, and the dequeuing of that packet from an output queue. In one embodiment, a virtual destination queue is determined for a packet. A policing decision is made whether to drop the packet or admit the packet to the output queue based on the occupancy level of the determined virtual destination queue, which is updated upon admission. Packets are dequeued in first-in-first-out order from the output queue. For a dequeued one or more packets, one or more of the occupancy values of the virtual destination queues are updated based a scheduling policy that is independent of the particular virtual destination queue(s) associated with the dequeued packets.

Dropping or admitting packets to an output queue using policy-based scheduling and virtual destination queue occupancy values

In one embodiment, packet memory and resource memory of a memory are independently managed, with regions of packet memory being freed of packets and temporarily made available to resource memory. In one embodiment, packet memory regions are dynamically made available to resource memory so that in-service system upgrade (ISSU) of a packet switching device can be performed without having to statically allocate (as per prior systems) twice the memory space required by resource memory during normal packet processing operations. One embodiment dynamically collects fragments of packet memory stored in packet memory to form a contiguous region of memory that can be used by resource memory in a memory system that is shared between many clients in a routing complex. One embodiment assigns a contiguous region no longer used by packet memory to resource memory, and from resource memory to packet memory, dynamically without packet loss or pause.

Dynamic temporary use of packet memory as resource memory

A method, system, and computer-readable medium for a network interface with adjustable rate are disclosed. For example, one method involves receiving a request to activate a virtual lane of an interface, where the request is received by a first node. The interface is configured to facilitate data communication between the first node and a second node, and the interface includes a plurality of virtual lanes that include at least one active virtual lane, and at least one inactive virtual lane. The method also involves, in response to receiving the request, negotiating with the second node to select an additional virtual lane from the at least one inactive virtual lane. The method involves activating the additional virtual lane. After the activating, the first node and the second node are configured to use the active virtual lane(s) and the additional virtual lane for data communication.

Network interface with adjustable rate

In one embodiment, a hierarchical scheduling system including multiple scheduling layers with layer bypass is used to schedule items (e.g., corresponding to packets). This scheduling of items performed in one embodiment includes: propagating first items through the hierarchical scheduling system and updating scheduling information in each of the plurality of scheduling layers based on said propagated first items as said propagated first items propagate through the plurality of scheduling layers, and bypassing one or more scheduling layers of the plurality of scheduling layers for scheduling bypassing items and updating scheduling information in each of said bypassed one or more scheduling layers based on said bypassing items. In one embodiment, this method is performed by a particular machine. In one embodiment, the operations of propagating first items through the hierarchical scheduling system and bypassing one or more scheduling layers are done in parallel.

Hierarchical scheduling system with layer bypass including updating scheduling information of a scheduling layer for each item whether or not it bypasses the scheduling layer

In one embodiment, an apparatus cascades groups of serialized data streams through devices, and performs operations based on information communicated therein. A received group of serialized data streams is aligned, but not framed, and forwarded to a next device (e.g., a next stage in a linear or tree cascaded formation of devices). Eliminating the framing and subsequent serialization operations performed on the received group of serialized data streams reduces the latency of communications through the cascaded devices, which can be significant when considered in relation to the high-speed communication rates. The received group of serialized data streams is also framed to create a sequence of data frames for processing (e.g., associative memory lookup operations, controlling multiplexing of received downstream serialized data streams, general or other processing) within the device.

Cascaded communication of serialized data streams through devices and their resulting operation

A fixed Generic Mapping Procedure (GMP) apparatus and method are provided to map client data to an optical transport frame. Client data to be mapped into a payload field of an optical transport frame is received and store in a memory. Timing information is generated based on bit and fractional bit granularity of client data mapped into the payload field of successive optical transport frames for use in recovering the client data from received optical transport frames.

Fixed generic mapping of client data to optical transport frame

In one embodiment, an Internet Protocol (IP) routing information base of a packet switching device is filtered to produce a significantly smaller subset of IP routes that are installed in one or more forwarding information bases for forwarding of IP packets. In one embodiment, these smaller forwarding information bases are located in memory local to a network processor to more quickly perform lookup operations thereon. In one embodiment, one or more of these forwarding information bases is used only for exact matching of addresses (not longest prefix matching). In one embodiment, the IP routes in these smaller forwarding information bases substantially correspond to packet switching devices in a network (e.g., core and edge routers), such as in contrast to including all the IP routes for devices external to the network.

Installing and using a subset of routes for forwarding packets

Growing community of inventors

Kanata, Canada

Mohammed Ismael Tatar