IP routing

A small example network with eight vertices and ten edges

Application of routing methodologies to IP networks.

- IP routing

17 related topics



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

A small example network with eight vertices and ten edges

Routing, in a narrower sense of the term, often refers to IP routing and is contrasted with bridging.


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

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T3 NSFNET Backbone, c. 1992.
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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.
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Computers and routers use routing tables in their operating system to direct IP packets to reach a node on a different subnetwork.

Point-to-Point Protocol over Ethernet

Network protocol for encapsulating Point-to-Point Protocol (PPP) frames inside Ethernet frames.

Figure 2. The TCP/IP model or Internet layering scheme and its relation to some common protocols.

On the customer-premises equipment, PPPoE may be implemented either in a unified residential gateway device that handles both DSL modem and IP routing functions or in the case of a simple DSL modem (without routing support), PPPoE may be handled behind it on a separate Ethernet-only router or even directly on a user's computer.

Classless Inter-Domain Routing

A Table of CIDR prefixes for IPv6, it shows the number of corresponding equivalent subnets for each prefix, as well as the number of the host identifier bits.

Classless Inter-Domain Routing (CIDR ) is a method for allocating IP addresses and for IP routing.

Heuristic routing

System used to describe how deliveries are made when problems in a network topology arise.

Diagram of different network topologies.

The IP routing protocols in use today are based on one of two algorithms: distance vector or link state.

Spanning Tree Protocol

Network protocol that builds a loop-free logical topology for Ethernet networks.

An example network. The numbered boxes represent bridges, that is switches in a LAN. The number is the bridge ID. The lettered clouds represent network segments. The smallest bridge ID is 3. Therefore, bridge 3 is the root bridge.
Path tie: The least-cost path to the root from network segment e goes through bridge 92. Therefore, the designated port for network segment e is the port that connects bridge 92 to network segment e.

Configuring connections between network equipment as layer-3 IP links and relying on IP routing for resiliency and to prevent loops is a popular alternative.


Any broadcast domain that is partitioned and isolated in a computer network at the data link layer (OSI layer 2).

Network Packet

Although it was possible to use IP routing to connect multiple Ethernet networks together, it was expensive and relatively slow.

Multilayer switch

Computer networking device that switches on OSI layer 2 like an ordinary network switch and provides extra functions on higher OSI layers.

Network Packet

Layer-3 switches typically support IP routing between VLANs configured on the switch.

Mesh networking

Local area network topology in which the infrastructure nodes (i.e. bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data to and from clients.

Illustration of a partially connected mesh network. A fully connected mesh network is where each node is connected to every other node in the network.

IP routing supports multiple paths from source to destination.

Locator/Identifier Separation Protocol

A "map-and-encapsulate" protocol which is developed by the Internet Engineering Task Force LISP Working Group.

The LISP Logo

as a locator for routing purposes, to identify where a network interface is located within a larger routing context