ĭistribution routers aggregate traffic from multiple access routers.
Some SOHO routers are capable of running alternative free Linux-based firmware like Tomato, OpenWrt or DD-WRT. Typically, they are optimized for low cost. This page configures Dynamic DNS.Īccess routers, including small office/home office (SOHO) models, are located at home and customer sites such as branch offices that do not need hierarchical routing of their own. Access, core and distribution Ī screenshot of the LuCI web interface used by OpenWrt. A hierarchical internetworking model for interconnecting routers in large networks is in common use. Large businesses may also need more powerful routers to cope with ever-increasing demands of intranet data traffic. The most powerful routers are usually found in ISPs, academic and research facilities. Smaller routers usually provide connectivity for typical home and office networks.Īll sizes of routers may be found inside enterprises. The largest routers (such as the Cisco CRS-1 or Juniper PTX) interconnect the various ISPs, or may be used in large enterprise networks. Routers may provide connectivity within enterprises, between enterprises and the Internet, or between internet service providers' (ISPs') networks. Routers may also be used to connect two or more logical groups of computer devices known as subnets, each with a different network prefix. Each network interface is used to enable data packets to be forwarded from one transmission system to another. It can also support different network layer transmission standards. It reads the header of each packet as it comes in, matches the destination to entries in the FIB supplied by the control plane, and directs the packet to the outgoing network specified in the FIB.Ī typical home or small office DSL router showing the telephone socket (left, white) to connect it to the internet using ADSL, and Ethernet jacks (right, yellow) to connect it to home computers and printers.Ī router may have interfaces for different types of physical layer connections, such as copper cables, fiber optic, or wireless transmission. Forwarding plane: This unit forwards the data packets between incoming and outgoing interface connections.The control-plane logic then strips non-essential directives from the table and builds a forwarding information base (FIB) to be used by the forwarding plane. Static and dynamic routes are stored in the routing table. It does this using internal pre-configured directives, called static routes, or by learning routes dynamically using a routing protocol. Control plane: A router maintains a routing table that lists which route should be used to forward a data packet, and through which physical interface connection.
The software that runs the router is composed of two functional processing units that operate simultaneously, called planes: Each router builds up a routing table, a list of routes, between two computer systems on the interconnected networks. When multiple routers are used in interconnected networks, the routers can exchange information about destination addresses using a routing protocol. 2.4 Internet connectivity and internal use.More sophisticated routers, such as enterprise routers, connect large business or ISP networks up to the powerful core routers that forward data at high speed along the optical fiber lines of the Internet backbone. The most familiar type of IP routers are home and small office routers that simply forward IP packets between the home computers and the Internet. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. When a data packet comes in on one of the lines, the router reads the network address information in the packet header to determine the ultimate destination. Ī router is connected to two or more data lines from different IP networks. the Internet) until it reaches its destination node. A packet is typically forwarded from one router to another router through the networks that constitute an internetwork (e.g. Data sent through the internet, such as a web page or email, is in the form of data packets. Routers perform the traffic directing functions on the Internet. A Cisco ASM/2-32EM router that was deployed at CERN in 1987Ī router is a networking device that forwards data packets between computer networks.