The Click modular router

Abstract

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.

Quality of service provisioning for composable routing elements

“…We have made our own changes to the vortex device driver to additionally support polling I/O, in which the device driver polls the network interface for packet arrivals (i.e., there is no interrupt overhead for receiving packets). Polling is much less expensive than interrupt processing, and can significantly increase the efficiency and stability of a router having to deal with frequent packet arrivals [6,8]. For the global router functions, we schedule them in the context of a single global flow, similar to the configuration shown in Fig.…”

“…While routing elements have been advanced in prior research and are supported in existing systems (e.g., [6]), their scheduling issues for providing quality of service (QoS) to network flows have not received much attention. In this paper, we present the CROSS/Linux router platform that supports configurable flow graphs of router elements as provided by the Click modular router [6].…”

“…In this paper, we present the CROSS/Linux router platform that supports configurable flow graphs of router elements as provided by the Click modular router [6]. Our research contributions beyond Click are in the area of element-related resource allocation and scheduling, which includes the following issues:…”

A context-aware architecture for QoS and transcoding management of multimedia streams in smart homes

“…The classification engine is build upon the Click Modular Router [18] tool running in user-space, while specific modules have been developed in order to recognize the application protocol generating the flow (these modules are based on a patter-matching schema derived from L7-filter [19]), associate each packet with a specific flow, and update statistics accordingly. The Network Probe can be viewed as a particular type of sensor, and thus it is virtualized within SAIL as a virtual sensor, where the transducers are associated to the measurements described above: mean and current bandwidth, number of active flows, mean and current arrival/departure rates, and number of bytes/packets arrived (see Figure 4).…”

Fast firewall implementations for software-based and hardware-based routers

“…Other solutions reported in the literature that can be implemented in software e.g., 16, 10 are either slow or take t o o m uch storage. With the advent of software based routers e.g., 13 , which are typically aimed at the edge router space where classi cation is particularly important, it is particularly important to nd fast software techniques for fast rewall implementations.…”