P Router

Abstract: 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.

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.

Abstract: An internetwork including a plurality of local area networks may include wireless and hard-wired local area networks. The internetwork may also include wide area network links between routers. The system includes routers between networks, which may be bridged networks. Certain routers are configured as home routers. Home routers bind two addresses for each mobile node on a given network when that node logs-in with a home router. Mobile nodes log-in with a home router that assigns a virtual address that does not change throughout a session. Each time, a mobile node roams to another network across a router boundary, the virtual address remains the same and all packets directed to the mobile node are received by the home router which advertises that it can reach the mobile node. As the mobile node roams, it reports back to the home router a local address to which the home router forwards all packets directed originally by correspondent nodes to the virtual address. Mobile nodes may log-in to a router many hops removed from a local area network of the situs. Mobile nodes may also roam across wide area links. The system is transparent to a user.

Abstract: A system and protocol are provided for routing data packets from a host (H2) on a LAN (L) through a virtual address (R4) belonging to a group or routers (126). The host (H2) is configured to point to the virtual address (R4) so that the packets it sends out of its LAN are always directed to a virtual router which may be any one of the group of routers (126). An active router (R5) in the group of routers emulates the virtual router (R4). A standby router (R6), also from the group of routers (126), backs up the active router (R5) so that if the active router becomes inoperative, the standby router (R6) automatically begins emulating the virtual router. The host (H2) does not know which router from the group (126) is actually handling the data packets it sends. If the standby router (R6) becomes inoperative or takes over for the active router, other routers in the group (126) hold an election to determine which of them should take over for the standby router.