Routing

A small example network with eight vertices and ten edges

Process of selecting a path for traffic in a network or between or across multiple networks.

- Routing
A small example network with eight vertices and ten edges

20 related topics

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Network Packet

Computer network

Set of computers sharing resources located on or provided by network nodes.

Set of computers sharing resources located on or provided by network nodes.

Network Packet
Common network topologies
A sample overlay network
Network links
Fiber optic cables are used to transmit light from one computer/network node to another
2007 map showing submarine optical fiber telecommunication cables around the world.
Computers are very often connected to networks using wireless links
An ATM network interface in the form of an accessory card. A lot of network interfaces are built-in.
A typical home or small office router showing the ADSL telephone line and Ethernet network cable connections
Firewalls
The TCP/IP model and its relation to common protocols used at different layers of the model.
Message flows between two devices (A-B) at the four layers of the TCP/IP model in the presence of a router (R). Red flows are effective communication paths, black paths are across the actual network links.
SONET & SDH
Asynchronous Transfer Mode
Routing calculates good paths through a network for information to take. For example, from node 1 to node 6 the best routes are likely to be 1-8-7-6, 1-8-10-6 or 1-9-10-6, as these are the shortest routes.
Partial map of the Internet, based on the January 15, 2005 data found on opte.org . Each line is drawn between two nodes, representing two IP addresses. The length of the lines is indicative of the delay between those two nodes. This graph represents less than 30% of the Class C networks reachable.

Address resolution and routing are the means that allow mapping of a fully connected IP overlay network to its underlying network.

Network Packet

Routing table

Data table stored in a router or a network host that lists the routes to particular network destinations, and in some cases, metrics (distances) associated with those routes.

Data table stored in a router or a network host that lists the routes to particular network destinations, and in some cases, metrics (distances) associated with those routes.

Network Packet

This forwarding table contains only the routes which are chosen by the routing algorithm as preferred routes for packet forwarding.

A small example network with eight vertices and ten edges

Static routing

A small example network with eight vertices and ten edges

Static routing is a form of routing that occurs when a router uses a manually-configured routing entry, rather than information from dynamic routing traffic.

Avaya ERS 2550T-PWR, a 50-port Ethernet switch

Network switch

Networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device.

Networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device.

Avaya ERS 2550T-PWR, a 50-port Ethernet switch
A modular network switch with three network modules (a total of 24 Ethernet and 14 Fast Ethernet ports) and one power supply.
A 5-port layer-2 switch without management functionality
A rack-mounted 24-port 3Com switch
A couple of managed D-Link Gigabit Ethernet rackmount switches, connected to the Ethernet ports on a few patch panels using Category 6 patch cables (all equipment is installed in a standard 19-inch rack)

Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality.

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Enhanced Interior Gateway Routing Protocol

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Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol that is used on a computer network for automating routing decisions and configuration.

Network Packet

Dynamic routing

Dynamic routing, also called adaptive routing,

Dynamic routing, also called adaptive routing,

Network Packet

Intermediate System to Intermediate System (IS-IS) determines the best route for data through a packet-switched network.

A high-level overview of network bridging, using the ISO/OSI layers and terminology

Network bridge

Computer networking device that creates a single, aggregate network from multiple communication networks or network segments.

Computer networking device that creates a single, aggregate network from multiple communication networks or network segments.

A high-level overview of network bridging, using the ISO/OSI layers and terminology

Bridging is distinct from routing.

Routing protocol classification computer networks.

Routing protocol

A routing protocol specifies how routers communicate with each other to distribute information that enables them to select routes between nodes on a computer network.

A routing protocol specifies how routers communicate with each other to distribute information that enables them to select routes between nodes on a computer network.

Routing protocol classification computer networks.

Routing algorithms determine the specific choice of route.

An illustration of hops in a wired network (assuming a 0-origin hop count ). The hop count between the computers in this case is 2.

Hop (networking)

Passed from one network segment to the next.

Passed from one network segment to the next.

An illustration of hops in a wired network (assuming a 0-origin hop count ). The hop count between the computers in this case is 2.

This prevents packets from endlessly bouncing around the network in the event of routing errors.

BGP state machine

Border Gateway Protocol

BGP state machine
A typical configuration of BGP RR deployment, as proposed by Section 6, RFC 4456.
BGP table growth on the Internet
Number of AS on the Internet vs number of registered AS

Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet.