Difference between EIGRP and OSPF

EIGRP stands for Enhanced Interior Gateway Routing Protocol. It is used to share information between routers lying in the same region. It can be easily implemented in small as well as large networks.

OSPF stands for Open Shortest Path first. It is used on variable-length subnet masking (VLSM) and discontinuous networks. It is a classless routing protocol.

Read through this article to find out more about EIGRP and OSPF and how these two protocols are different from each other.

What is EIGRP?

EIGRP is an advanced distance-vector routing protocol for automating routing decisions and configuration on a computer network. Cisco Systems designed the protocol as a proprietary protocol that could only be used on Cisco routers.

EIGRP is an OSI model network layer protocol. It is a dynamic routing protocol that finds the optimal path to transmit a message between any two layer-3 devices.

• EIGRP utilizes measurements to determine the optimal path between two EIGRP-enabled layer-3 devices (routers or switches).

• If neighbor routers exist in the same region, EIGRP is utilized to exchange information from one router to the others.

• It's a complicated protocol, however it's relatively easier to set up and use in both small and big networks.

• It's also a hybrid protocol because it uses both distance vector and link-state routing protocols.

• EIGRP doesn't use the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP), which means EIGRP communication is not identified by a port number. EIGRP, on the other hand, is meant to be used on top of layer-3, i.e., the IP protocol.

• Because EIGRP does not utilize TCP for transmission, it relies on Cisco's Reliable Transport Protocol (RTP) to ensure that EIGRP router updates reach all neighbors.

• Other techniques in the dependable transport protocol help to enhance efficiency and facilitate multicasting. EIGRP's multicast address is 224.0.0.10.

EIGRP has four basic components −

• Neighbor discovery and recovery,

• Reliable transfer protocol,

• DUAL Finite State Machine, and

• Protocol Dependent Modules.

With IGRP routers, EIGRP enables compatibility and seamless interoperability. In addition, EIGRP can be activated in strategic locations with minimal impact on IGRP performance.

EIGRP can support rapid convergence for changes in the network topology. Through Equal-Cost Multi-Path (ECMP) and unequal-cost load sharing, it makes better use of the link. It supports both IPv4 and IPv6 networks.

One of the disadvantages of EIGRP is that the routing protocol can be accessible with CISCO network devices only. However, EIGRP is the most advanced routing protocol that uses distance vectors and state route connections for determining the best route path.

What is OSPF?

Open Shortest Path First (OSPF) is a classless routing system that also aids discontiguous networks and variable-length subnet masking (VLSM).

• OSPF is a link-state routing protocol that uses its own shortest path first (SPF) algorithm to identify the optimal path between the source and destination routers.

• A link-state routing protocol employs the notion of triggered updates, in which updates are only triggered when a change in the learned routing table is detected, as opposed to the distance-vector routing protocol, in which the routing table is shared at a period of time.

• OSPF is an Interior Gateway Protocol (IGP) created by the Internet Engineering Task Force (IETF). It is a protocol that seeks to move packets inside a large autonomous system or routing domain. It's a network layer protocol that runs on port number 89 and utilizes the AD value 110.

OSPF operates within a single autonomous system and employs the link-state routing algorithm. In big business networks, OSPF is a commonly utilized IGP. OSPF supports the Classless Inter-Domain Routing (CIDR) addressing paradigm.

Based on an algorithm, routing protocols such as OSPF determine the shortest path to a destination across the network. The Routing Information Protocol (RIP), the first widely used routing protocol, computed the shortest path based on hops or the number of routers that an IP packet had to pass through to reach the target host. Dynamic routing, in which routing tables update as the network topology changes, was successfully achieved by RIP.

The major benefits of using OSPF are as follows −

• OSPF is suitable for handling large and diverse networks than the Routing Information Protocol (RIP) equidistant vector routing algorithm. When your network topology changes, OSPF can quickly recalculate routes.

• You can divide an autonomous system (AS) into multiple areas and use OSPF to reduce the size of the OSPF routing traffic and the link-state database of each site to keep the area topology different.

• OSPF supports multipath routing at the exact cost. It is possible to add the same routes with different next hops to the TCP stack.

Difference between EIGRP and OSPF

The following table highlights the major differences between EIGRP and OSPF −

Conclusion

EIGRP is a routing protocol that allows routers in the same autonomous system to share routes. Unlike other well-known routing protocols like RIP, EIGRP transmits incremental updates, decreasing the router's effort and the quantity of data that must be transferred.

In an OSPF network, routers or systems in the same area share a linkstate database that describes the site's topology. Each router on the network creates its link-state database based on the link state advertisement (LSA) received from all other routers or systems in the same area.

The most important point that you should note here is that EIGRP uses a distance vector routing protocol, whereas OSPF uses a link-state routing protocol.

Kiran Kumar Panigrahi

Updated on: 28-Jul-2022

2K+ Views

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