Clicks is a new software architecture for building flexible and configurable routers. A Click router is assembled from packet processing modules called elements. Individual elements implement simple router functions like packet classification, queuing, scheduling, and interfacing with network devices. A router configurable is a directed graph with elements at the vertices; packets flow along the edges of the graph. Several features make individual elements more powerful and complex configurations easier to write, including pull connections, which model packet flow drivn by transmitting hardware devices, and flow-based router context, which helps an element locate other interesting elements. Click configurations are modular and easy to extend. A standards-compliant Click IP router has 16 elements on its forwarding path; some of its elements are also useful in Ethernet switches and IP tunnelling configurations. Extending the IP router to support dropping policies, fairness among flows, or Differentiated Services simply requires adding a couple of element at the right place. On conventional PC hardware, the Click IP router achieves a maximum loss-free forwarding rate of 333,000 64-byte packets per second, demonstrating that Click's modular and flexible architecture is compatible with good performance.

The click modular router

Network Calculus.- Application of Network Calculus to the Internet.- Basic Min-plus and Max-plus Calculus.- Min-plus and Max-plus System Theory.- Optimal Multimedia Smoothing.- FIFO Systems and Aggregate Scheduling.- Adaptive and Packet Scale Rate Guarantees.- Time Varying Shapers.- Systems with Losses.

Network Calculus: A Theory of Deterministic Queuing Systems for the Internet

Click is a new software architecture for building flexible and configurable routers. A Click router is assembled from packet processing modules called elements. Individual elements implement simple router functions like packet classification, queueing, scheduling, and interfacing with network devices. Complete configurations are built by connecting elements into a graph; packets flow along the graph's edges. Several features make individual elements more powerful and complex configurations easier to write, including pull processing, which models packet flow driven by transmitting interfaces, and flow-based router context, which helps an element locate other interesting elements.We demonstrate several working configurations, including an IP router and an Ethernet bridge. These configurations are modular---the IP router has 16 elements on the forwarding path---and easy to extend by adding additional elements, which we demonstrate with augmented configurations. On commodity PC hardware running Linux, the Click IP router can forward 64-byte packets at 73,000 packets per second, just 10% slower than Linux alone.

/pdf/the-click-modular-router-1nn6g98t3q.pdf

The Click modular router

This document describes the use of RSVP (Resource Reservation Protocol), including all the necessary extensions, to establish label-switched paths (LSPs) in MPLS (Multi-Protocol Label Switching) Since the flow along an LSP is completely identified by the label applied at the ingress node of the path, these paths may be treated as tunnels A key application of LSP tunnels is traffic engineering with MPLS as specified in RFC 2702

RSVP-TE: Extensions to RSVP for LSP Tunnels

This document defines a general use Differentiated Services (DS) [Blake] Per-Hop-Behavior (PHB) Group called Assured Forwarding (AF). The AF PHB group provides delivery of IP packets in four independently forwarded AF classes. Within each AF class, an IP packet can be assigned one of three different levels of drop precedence. A DS node does not reorder IP packets of the same microflow if they belong to the same AF class.

Assured Forwarding PHB Group

This document describes CoDel (Controlled Delay) -- a general
framework that controls bufferbloat-generated excess delay in modern
networking environments. CoDel consists of an estimator, a setpoint,
and a control loop. It requires no configuration in normal Internet
deployments.

/pdf/controlled-delay-active-queue-management-4vgca1zatt.pdf

Controlled Delay Active Queue Management

Differentiated Services Operational Model and Definitions

A network device identifies a non-adaptive flow as follows. The network device drops packets on a random basis using a Random Early Detection (RED) algorithm. A classifier reads indicia of a flow from at least one field of a header of a packet received by the network device. The network device calculates a drop interval for packets of the flow dropped by the RED algorithm, in response to a time at which the packets were dropped. The network device then applies a statistical test to drop intervals of a plurality of flows in order to identify the non-adaptive flow.

Method of detecting non-responsive network flows

The `Virtual Wire' Per-Domain Behavior

A Random Early Detection (RED) policer in accordance with the invention does not tail-drop arriving packets as being non-conforming. For instance, because the RED policer uses a running estimate such as an exponential weighted moving average (EWMA), for example, it allows the policer to absorb traffic bursts. The policer uses randomization in choosing which packets to drop; with this method, the probability of dropping a packet from a particular sending node is roughly proportional to the node's bandwidth share, hence the packets of different flows are fairly dropped.

Kathleen Nichols

Papers

Controlled Delay Active Queue Management

Differentiated Services Operational Model and Definitions

Method of detecting non-responsive network flows

The `Virtual Wire' Per-Domain Behavior

Random early detection policer using randomization of packet drops