Rack containing several enterprise class routers connected to multiple networks
Routing protocol classification computer networks.
Home and small office wireless router
A 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.
A screenshot of the LuCI web interface used by OpenWrt. This page configures Dynamic DNS.
The first ARPANET router, the Interface Message Processor was delivered to UCLA August 30, 1969, and went online October 29, 1969

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

When multiple routers are used in interconnected networks, the routers can exchange information about destination addresses using a routing protocol.

- Router (computing)
Rack containing several enterprise class routers connected to multiple networks

3 related topics

Alpha

The Internet Messenger by Buky Schwartz, located in Holon, Israel

Internet

Global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices.

Global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices.

The Internet Messenger by Buky Schwartz, located in Holon, Israel
T3 NSFNET Backbone, c. 1992.
ICANN headquarters in the Playa Vista neighborhood of Los Angeles, California, United States.
2007 map showing submarine fiberoptic telecommunication cables around the world.
Packet routing across the Internet involves several tiers of Internet service providers.
Number of mobile cellular subscriptions 2012–2016
As user data is processed through the protocol stack, each abstraction layer adds encapsulation information at the sending host. Data is transmitted over the wire at the link level between hosts and routers. Encapsulation is removed by the receiving host. Intermediate relays update link encapsulation at each hop, and inspect the IP layer for routing purposes.
Conceptual data flow in a simple network topology of two hosts (A and B) connected by a link between their respective routers. The application on each host executes read and write operations as if the processes were directly connected to each other by some kind of data pipe. After the establishment of this pipe, most details of the communication are hidden from each process, as the underlying principles of communication are implemented in the lower protocol layers. In analogy, at the transport layer the communication appears as host-to-host, without knowledge of the application data structures and the connecting routers, while at the internetworking layer, individual network boundaries are traversed at each router.
A DNS resolver consults three name servers to resolve the domain name user-visible "www.wikipedia.org" to determine the IPV4 Address 207.142.131.234
Creating a subnet by dividing the host identifier
This NeXT Computer was used by Tim Berners-Lee at CERN and became the world's first Web server.
Share of population using the Internet. See or edit source data.
Internet users per 100 population members and GDP per capita for selected countries.
Internet users per 100 inhabitants Source: International Telecommunication Union.
Internet users in 2015 as a percentage of a country's population Source: International Telecommunication Union.
'''Fixed broadband Internet subscriptions in 2012
as a percentage of a country's population''' Source: International Telecommunication Union.
'''Mobile broadband Internet subscriptions in 2012
as a percentage of a country's population''' Source: International Telecommunication Union.
Banner in Bangkok during the 2014 Thai coup d'état, informing the Thai public that 'like' or 'share' activities on social media could result in imprisonment (observed 30 June 2014).
Internet users by language<ref name=NIUBL-IWS>{{cite web|url=http://www.internetworldstats.com/stats7.htm|title=Number of Internet Users by Language|archive-url=https://web.archive.org/web/20120426122721/http://www.internetworldstats.com/stats7.htm|archive-date=26 April 2012|website=Internet World Stats, Miniwatts Marketing Group|date=31 May 2011|access-date=22 April 2012}}</ref>
Website content languages<ref name=UofCLBWApril2013>{{cite web|title=Usage of content languages for websites|url=http://w3techs.com/technologies/overview/content_language/all|work=W3Techs.com|access-date=26 April 2013|archive-url=https://www.webcitation.org/66ZQzUXh6?url=http://w3techs.com/technologies/overview/content_language/all|archive-date=31 March 2012|url-status=live}}</ref>

As with any computer network, the Internet physically consists of routers, media (such as cabling and radio links), repeaters, modems etc. However, as an example of internetworking, many of the network nodes are not necessarily internet equipment per se, the internet packets are carried by other full-fledged networking protocols with the Internet acting as a homogeneous networking standard, running across heterogeneous hardware, with the packets guided to their destinations by IP routers.

Routing tables are maintained by manual configuration or automatically by routing protocols.

Encapsulation of application data carried by UDP to a link protocol frame

Internet Protocol

Network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries.

Network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries.

Encapsulation of application data carried by UDP to a link protocol frame
A timeline for the development of the transmission control Protocol TCP and Internet Protocol IP.
First Internet demonstration, linking the ARPANET, PRNET, and SATNET on November 22, 1977

IP routing is performed by all hosts, as well as routers, whose main function is to transport packets across network boundaries.

Routers communicate with one another via specially designed routing protocols, either interior gateway protocols or exterior gateway protocols, as needed for the topology of the network.

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.

Previous proposals such as IntServ, DiffServ, and IP multicast have not seen wide acceptance largely because they require modification of all routers in the network.

In packet-switched networks, routing protocols direct packet forwarding through intermediate nodes.