Click Notes I-overview

Click are a modular router toolkit written mainly in C + +, which can be run in both user spaces and OS kernel s Pace. Since its invention into late 1990s by Eddie Kohler, Click are has gained great successes in both and industry. This is series of notes aims to (1) Introduce click platform, (2) analyze the implementation of Click, and (3) discuss som E General problems related to operating System and network programming. Router Models Click Architecture Elements Packets connections References Router Models

Click is developed based on an abstract router model. Routers are viewed as pure packet processors:packets arrive on one network interface, travel through the packet processor ' s forwarding path, and are emitted on another network interface. In routers, packets flow through the forwarding paths, which behave and just like the pipelines. Packets'll lose their identity after they arrive the target-only data would be transferred to applications (running on H OST). One significant differences between routers and hosts Is:in packet (processors, packets move horizontally between peers, n OT vertically between application layers.

Click also used an important observation-the packet operation are to basis of computer. Firewall limits access to a protected network, often by dropping inappropriate. Network address translators allow a large set of machines to share address; They work by rewriting packet headers, and occasionally some data. Load balancers send packets to one of the a set of servers, dynamically choosing a server based on load or some APPL Ication characteristic. Therefore, most Click elements center on packet operations. -#sthash the full post at:http://www.bo-yang.net/2014/12/23/click-notes-overview/. URHLBFTW.DPUF