Routing protocols determine how your data it s okay to that destination and also helps to do that procedure as smooth together possible. Learn about the various types of routing protocol that you will certainly encounter in a modern-day networking environment. 

Routing is one of the most basic areas the networking the an administrator has to know. Routing protocols determine how your data it s okay to the destination and also helps to make that routing procedure as smooth together possible. However, there are so numerous different types of routing protocol that it deserve to be very an overwhelming to save track of lock all!

Router protocols include:Routing info Protocol (RIP)Interior Gateway Protocol (IGRP)Open Shortest Path an initial (OSPF)Exterior Gateway Protocol (EGP)Enhanced inner Gateway Routing Protocol (EIGRP)Border Gateway Protocol (BGP)Intermediate System-to-Intermediate device (IS-IS)

Before we obtain to looking at the routing protocols themselves, it is important to emphasis on the category of protocols.

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All routing protocols deserve to be classified into the following:Distance Vector or attach State ProtocolsInterior Gateway Protocols (IGP) or Exterior Gateway Protocols (EGP)Classful or Classless Protocols

Distance Vector and Link State Protocols

Distance Vector link State
Sends entire routing table during updates Only provides attach state information
Sends routine updates every 30-90 seconds Uses motivated updates
Broadcasts updatesMulti casts updates
Vulnerable come routing loopsNo threat of routing loops

Distance vector routing protocols room protocols that usage distance to work out the best routing path for packets within a network.

These protocols measure up the distance based upon how plenty of hops data needs to pass to gain to the destination. The number of hops is essentially the variety of routers it takes to with the destination.

Generally, distance vector protocols send a routing table full of info to bordering devices. This method makes lock low investment for administrators together they have the right to be deployed without much need to it is in managed. The only worry is that they require more bandwidth come send ~ above the routing tables and can run right into routing loops as well.

Link State Routing Protocols

Link state protocols take it a different approach to detect the finest routing course in that they share information with other routers in proximity. The route is calculated based upon the rate of the path to the destination and also the cost of resources.

Link state routing protocols use an algorithm to work-related this out. Among the crucial differences to a street vector protocol is that attach state protocols nothing send the end routing tables; instead, routers inform each other as soon as route alters are detected.

Routers making use of the connect state protocol creates three species of tables; neighbor table, topology table, and routing table. The neighborhood table shop details of surrounding routers using the attach state routing protocol, the topology table stores the whole network topology, and also the routing table stores the most efficient routes.

IGP and also EGPs

Routing protocols can also be categorized together Interior Gateway Protocols (IGPs) or Exterior Gateway Protocols (EGPs).


IGPs space routing protocols the exchange routing details with other routers within a single autonomous mechanism (AS). An as is defined as one network or a arsenal of networks under the control of one enterprise. The firm AS is for this reason separate native the ISP AS.

Each the the following is classified together an IGP:Open Shortest Path very first (OSPF)Routing details Protocol (RIP)Intermediate system to Intermediate system (IS-IS)Enhanced interior Gateway Routing Protocol (EIGRP)


On the various other hand, EGPs are routing protocols that are offered to transport routing information in between routers in different autonomous systems. These protocols room more complicated and BGP is the just EGP protocol that you’re most likely to encounter. However, the is important to keep in mind that there is one EGP protocol called EGP.

Examples of EGPs include:Border Gateway Protocol (BGP)Exterior Gateway Protocol (EGP)The ISO’s InterDomain Routing Protocol (IDRP)

Types that Routing Protocol

Routing Protocols Timeline

1982 – EGP1985 – IGRP1988 – RIPv11990 – IS-IS1991 – OSPFv21992 – EIGRP1994 – RIPv21995 – BGP1997 – RIPng1999 – BGPv6 and also OSPFv32000 – IS-ISv6

Routing details Protocol (RIP)

Routing details Protocol or RIP is one of the an initial routing protocols to it is in created. RIP is used in both Local Area Networks (LANs) and also Wide Area Networks (WANs), and likewise runs ~ above the application layer that the OSI model. There space multiple version of RIP consisting of RIPv1 and RIPv2. The original version or RIPv1 identify network paths based upon the IP destination and the hop counting of the journey.

RIPv1 interacts v the network by broadcasting its IP table to every routers connected to the network. RIPv2 is a little much more sophisticated than this and sends out its routing table on to a multicast address. RIPv2 also uses authentication to keep data more secure and also chooses a subnet mask and gateway because that future traffic. The main limitation of RIP is that it has a maximum hop count of 15 which provides it unsuitable for larger networks.

See also: LAN surveillance tools

Interior Gateway Protocol (IGRP)

Interior Gateway Protocol or IGRP is a distance vector routing protocol created by Cisco. IGRP was designed to construct on the foundations laid under on RIP to function much more effectively within larger linked networks and also removed the 15 hop lid that was placed on RIP. IGRP offers metrics such together bandwidth, delay, reliability, and load to to compare the viability of routes within the network. However, just bandwidth and delay are supplied under IGRP’s default settings.

IGRP is best for larger networks due to the fact that it broadcasts updates every 90 seconds and also has a best hop counting of 255. This allows it come sustain larger networks than a protocol like RIP. IGRP is also widely used due to the fact that it is resistant come routing loops due to the fact that it updates itself instantly when route alters occur in ~ the network.

Open Shortest Path first (OSPF)

Open Shortest Path very first or OSPF protocol is a link-state IGP the was tailor-made because that IP networks using the Shortest route First (SPF) algorithm. The SPF routing algorithm is offered to calculate the shortest route spanning-tree come ensure reliable data transmission of packets. OSPF routers preserve databases detailing information around the bordering topology of the network. This database is filled with data taken indigenous Link State Advertisements (LSAs) sent out by various other routers. LSAs space packets that information information around how countless resources a provided path would take.

OSPF additionally uses the Dijkstra algorithm come recalculate network paths once the topology changes. This protocol is also reasonably secure together it can authenticate protocol transforms to store data secure. That is supplied by many organizations since it’s scalable to big environments. Topology changes are tracked and also OSPF deserve to recalculate endangered packet routes if a previously-used route has been blocked.

Exterior Gateway Protocol (EGP)

Exterior Gateway Protocol or EGP is a protocol that is supplied to exchange data in between gateway hosts the neighbor each various other within autonomous systems. In various other words, EGP gives a forum for routers to share information across different domains. The many high profile example of one EGP is the web itself. The routing table that the EGP protocol has known routers, route costs, and network addresses of surrounding devices. EGP to be widely-used by bigger organizations but has because been replaced by BGP.

The factor why this protocol has actually fallen out of donate is the it doesn’t support multipath networking environments. The EGP protocol functions by keeping a database of surrounding networks and the routing routes it can take to with them. This route info is sent out on to associated routers. When it arrives, the tools can upgrade their routing tables and undertake an ext informed path an option throughout the network.

Enhanced internal Gateway Routing Protocol (EIGRP)

Enhanced interior Gateway Routing Protocol or EIGRP is a street vector routing protocol that is supplied for IP, AppleTalk, and NetWare networks. EIGRP is a Cisco proprietary protocol that was design to follow on indigenous the original IGRP protocol. As soon as using EIGRP, a router takes information from that neighbors’ routing tables and also records them. Next-door neighbors are queried for a route and when a readjust occurs the router informs its neighbors around the change. This has actually the end result of making bordering routers aware of what is walk on in nearby devices.

EIGRP is equipped through a number of features come maximize efficiency, including Reliable deliver Protocol (RTP) and also a Diffusing update Algorithm (DUAL). Packet transmissions are made more effective because routes room recalculated to rate up the convergence process.

Border Gateway Protocol (BGP)

Border Gateway Protocol or BGP is the routing protocol the the net that is classified together a distance route vector protocol. BGP was designed to change EGP with a decentralized approach to routing. The BGP best Path an option Algorithm is provided to select the ideal routes because that data packet transfers. If you nothing have any custom setups then BGP will pick routes through the shortest route to the destination.

However countless administrators choose to adjust routing decisions to criteria in line through their needs. The ideal routing path an option algorithm have the right to be customized by transforming the BGP cost ar attribute. BGP deserve to make routing decision based factors such together weight, regional preference, in your ar generated, AS_Path length, beginning type, multi-exit discriminator, eBGP over iBGP, IGP metric, router ID, cluster list and also neighbor IP address.

BGP just sends update router table data once something changes. As a result, there is no auto-discovery of topology alters which way that the user needs to configure BGP manually. In terms of security, BGP protocol can be authenticated for this reason that just approved routers deserve to exchange data with each other.

Intermediate System-to-Intermediate device (IS-IS)

Intermediate System-to-Intermediate device (IS-IS) is a link-state, IP routing protocol and IGPP protocol offered on the internet to send IP routing information. IS-IS offers a modified variation of the Dijkstra algorithm. An IS-IS network consists of a range of contents including finish systems, (user devices), intermediate equipment (routers), areas, and domains.

Under IS-IS routers space organized right into groups called areas and multiple locations are grouped with each other to make up a domain. Routers within the area are put with great 1 and also routers that connect segments together room classified as Layer 2. There space two species of network addresses provided by IS-IS; Network Service accessibility Point (NSAP) and also Network entity Title (NET).

Classful and also Classless Routing Protocols

Routing protocols can also be categorized together classful and also classless routing protocols. The distinction between these 2 comes under to how they go about executing routing updates. The debate in between these two creates of routing is regularly referred to as classful vs classless routing.

Classful Routing Protocols

Classful routing protocols nothing send subnet mask information throughout routing updates but classless routing protocols do. RIPv1 and IGRP are thought about to it is in classful protocols. These two are classful protocols because they don’t encompass subnet mask details in your routing updates. Classful routing protocols have because become outdated by classless routing protocols.

Classless Routing Protocols

As discussed above, classful routing protocols have been replaced by classless routing protocols. Classless routing protocols send IP subnet mask information throughout routing updates. RIPv2, EIGRP, OSPF, and IS-IS room all types of class routing protocols that incorporate subnet mask info within updates.

Dynamic Routing Protocols

Dynamic routing protocols are another form of routing protocols the are vital to contemporary enterprise-grade networks. Dynamic routing protocols allow routers to automatically add information to your routing tables from linked routers. With these protocols, routers send out topology update whenever the topological structure of the network changes. This means that the user doesn’t have to worry about keeping network courses up-to-date.

One the the main benefits of dynamic routing protocols is that they minimize the require to control configurations. The downside is that this come at the price of allocating resources favor CPU and also bandwidth to save them running on an recurring basis. OSPF, EIGRP, and RIP are taken into consideration to be dynamic routing protocols.

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Routing Protocols and also Metrics

No issue what kind of routing protocol is gift used, there will be clean metrics the are offered to measure up which path is the ideal to take. A routing protocol have the right to identify multiple courses to a location network yet needs to have actually the ability to work-related out i beg your pardon is the most efficient. Metrics permit the protocol to recognize which routing path have to be preferred to administer the network through the best service.

The simplest metric to take into consideration is hop count. The RIP protocol offers hop count to measure up the street it takes for a data packet to with its destination. The more hops the a packet has to travel through, the farther the packet has to travel. For this reason the RIP protocol aims to choose routes if minimizing hops whereby possible. Over there are plenty of metrics besides hop count the are provided by IP routing protocols. Metrics used include:

Hop count – measures the number of routers the a packet should travel throughBandwidth – choose the routing path based upon which has actually the highest bandwidthDelay – choose the routing path based upon which bring away the the very least timeReliability – Assesses the likelihood the a network link will fail based on error counts and also previous failuresCost – A value configured by the administrator or the IOS which is offered to measure up the cost of a route based on one metric or a range of metricsLoad – choose the routing path based upon the website traffic utilization of connected links

Metrics by Protocol Type