Network routing is the decision-making process for routers as they learn available routes, build tables, and send data on the fastest and cheapest paths. These tasks optimize efficiency and cost-effective communication to rapidly deliver data packages to their recipients around the world.
This article will cover how network routing works, the subcategories of protocols it relies on, and the algorithms that power it. With the proper information, any organization can optimize their network routing for a streamlined and secure communication infrastructure.
Table of Contents
How network routing works
Each router has a log of potential pathways and routes called the routing table. The router uses this table to chart and communicate with neighboring networks, devices, and other routers. Admins of these networks must update their routers for proper network infrastructure health so they have all the knowledge and capabilities to communicate effectively.
When a router receives a data packet, it completes a minimal scan for destination details. It’s like the airport attendant checking tickets to see which terminal a passenger needs. The router inspects the packet and begins determining the best path forward.
Routing protocols dictate how routers communicate and what they deem valuable in the flight path. They consider factors like cost, timeliness, and neighboring network bandwidth. Combined with the wealth of information stored in the routing table, the router algorithm computes the appropriate path.
Next, the data package hops between routers until it lands on the right network. From there, the router will disseminate the data to the proper device.
Network routing’s decision-making is crucial to the reliability and safety of data communication. Every person and business shares information, and it’s often sensitive data like purchase orders and shipping notices—especially for businesses. If the information fails to deliver or arrives at the wrong network, this could spell disaster for customer privacy and result in breaches in financial security.
Great network routing also improves the integrity of the network by warding off link failure and rapid route recalculations that slow procedures and connectivity down. Network routing charts the best path to send and receive data in a secure manner.
Top 4 routing protocols
In the network routing process, routing protocols dictate how routers communicate. Each protocol has its own rules that uniquely distribute files between devices or access the internet.
Distance vector protocols
In distance vector protocols, the router continually updates its routing table with information from connected neighboring routers and devices. While its data is fresh and accurate, these constant updates place a lot of bandwidth on the network and slow convergence.
Additionally, if the router deems a particular path unavailable, all network router tables are subsequently updated. Here, current information is at the cost of speediness.
Link-state protocols advertise routing updates only when they are happening, unlike distance vector protocols that update at regular intervals regardless of new information. When a link-state router obtains data for its table, it floods the information to neighboring routers for consolidation.
This is better for bandwidth and convergence speed, but may allow outdated information to remain in the routing table for a longer period of time.
Routing Information Protocol (RIP)
Routing Information Protocol (RIP) works in intra-domain networks. It also relies on hop count as a valuable metric. On its most basic level, RIP is only sometimes preferred because of slow convergence and scalability, but its subtypes improve in these areas.
Classful and classless routing protocols
Classful and classless routing protocols work with subnetworks within an IP network. Subnet masks divide an IP into parts, identifying the host computer and the connected network. Classful routers do not define the subnet mask in its consistent updates, which ensures updates go to all devices and routers in the network. Classless routers do determine the subnet masks, which provides less bandwidth consumption. Here, updates only roll out to the necessary subnetworks.
Network routing types
Network routing types are subcategories of the protocols that dictate router communication, such as Interior, Enhanced Interior, and Exterior Gateways (IGRP, EIGRP, and EGP, respectively); Open Shortest Path First; and Border Gateway Protocol (BGP).
Because each type values different factors to determine the data package’s path, they fluctuate in popularity and effectiveness. The right routing type for an organization may also depend on its unique needs, employee population and business model.
Interior and Enhanced Interior Gateways (IGRP and EIGRP)
IGRP is a classful protocol built off the standards of RIP. However, it can complete more hop counts, even up to 255. Routing information and tables automatically update, which means higher bandwidth and slow convergence. IGRP routers also limit the exchange of information to the organization’s personal network.
On a different note, EIGRP is a classless type founded in RIP, meaning data delivers faster and more efficiently.
Exterior Gateway Protocol (EGP)
EGP considers costs and IP addresses of nearby routers to dictate the data package’s path. It will routinely communicate and update the routing table with information on neighboring routers’ status and effectiveness.
As an important note, EGPs have been largely phased out as they struggle to adapt to multipath routing.
Open Shortest Path First (OSPF)
OSPF, as its name suggests, always chooses the shortest path. The router builds an idea of the network topology and collection of other routers in the network. When a data packet arrives, the router considers network paths, distance, and resource consumption to determine the quickest route possible.
Because of its efficiency and scalability, OSPF is popular with vast commercial or enterprise networks that may have dozens of routers in their building.
Integrated IS-IS bases its decision-making on grouping routers into areas. Interestingly, the router does not consider IP addresses. Instead, it monitors network service access points and network entity titles to build a clear picture of the router landscape.
Border Gateway Protocol (BGP)
Border Gateway Protocol (BGP) is the most popular routing type today. While similar to exterior gateway protocols, BGP has higher capabilities and can easily support multipath routing.
By default, BGP also chooses the shortest path as the best, but its decision-making can be configured to fit any organization’s needs. New and improved authentication practices also ensure only verified routers can share information with each other.
What are routing algorithms?
Routing algorithms implement the information and communications from the protocols and compute a path for the data packages. They are either adaptive or non-adaptive.
Adaptive routing algorithms
Adaptive algorithms use dynamic routing depending on the conditions and quality of the network. Is there heavy traffic, estimated transit time and hop count on this proposed network? If adaptive routing algorithms recognize these metrics, they will likely avoid that path.
There are two subcategories of adaptive algorithms—centralized and isolated routing—which determine routes based on where their information on costs originated.
- Centralized adaptive routing relies on global knowledge of the least-costly path.
- Isolated routing utilizes local information.
Non-adaptive routing algorithms
Non-adaptive algorithms use a routing table to store information. The information is static and not dependent on current network qualities or conditions. The subcategories of flooding and random walks differentiate where the data packet goes.
- Flooding sends the packet to all outgoing links, which could be helpful for peer-to-peer file sharing and distributing protocol updates quickly.
- Random walks go to any neighbor randomly, utilizing alternate routes.
Bottom line: Understanding network routing protocols
Network routing is a process of protocols and algorithms that communicate and compute the best paths for delivery. In a high-speed world, routing is essential for maintaining capacity and eliminating traffic congestion. It also helps to sort out a network landscape, as it identifies devices, neighboring routers, and networks, and organizes information about them. Network routing is crucial to receive and send data safely and efficiently.
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