Difference between EIGRP and OSPF

EIGRP and OSPF are inner gateway routing protocols that aid in the selection of routes for data transmission or sharing by interacting with routers. The earlier protocol EIGRP utilizes is a distance vector routing protocol, and the later protocol, OSPF, utilizes a link-state routing protocol. However, EIGRP and OSPF can both learn dynamic routes for the network, and there are many differences between them. For example, the EIGRP protocol is a Cisco proprietary IGP, and it is only utilized in Cisco networks. In contrast, OSPF is the enterprise network's open standards IGP.

In this article, you will learn about the difference between EIGRP and OSPF. But before discussing the differences, you must know about EIGRP and OSPRF with their advantages and disadvantages.

What is EIGRP?

EIGRP is an abbreviation for "Enhanced Interior Gateway Routing Protocol". It is a distance vector protocol that is based on Cisco that runs on DUAL (Diffusing Update Algorithm). It is mainly utilized to share data from one router to neighbouring routers in the same region. However, EIGRP is a complicated protocol, and it is easy to configure and operate in both small and large networks. It was designed to resolve the problems of traditional distance vector routing protocols like RIP (Routing Information Protocol) and IGRP, which were complex to scale to meet the needs of the network.

EIGRP is a hybrid protocol as it combines aspects of the distance vector routing protocol and the link-state routing protocol. EIGRP gets its updates from its neighbours, like the distance vector routing system. Similarly, the EIGRP protocol maintains a topology table of the announced routes and employs the Diffusing Update Algorithm (DUAL) as the link-state protocol to select a loop-free path.

Advantages and Disadvantages of EIGRP

There are various advantages and disadvantages of EIGRP. Some main advantages and disadvantages of EIGRP are as follows:

Advantages

1. EIGRP configuration was developed to be simple to use.
2. Manual route summarization is a more advanced capability of EIGRP. It increases stability while decreasing routing table size.
3. It may route several layer protocols with protocol-dependent modules.
4. It will converge in 200 milliseconds.
5. If the destination has more than one connection, it will determine the difference between them.
6. It is the protocol that performs unequal cost load balancing.

Disadvantages

1. It is a distance vector routing system that depends on neighbour-provided routes.
2. It may only be accessed with CISCO network devices.
3. It doesn't support future applications because it is not extensible.

What is OSPF?

OSPF is an abbreviation for "Open Shortest Path first". It is an open standard routing protocol similar to the EIGRP protocol, and it is an open IETF standard that may be utilized in many networks. The OSPF's development focused on developing a link-state protocol that may offer more scalability and efficiency than the Routing Information Protocol. It runs on protocol number 89, uses the AD value 110, and has a dependable transportation mechanism.

OSPF is a low-class routing protocol that also helps with variable-length subnet masking (VLSM) and discontinuous networks. It utilizes multicast addresses 224.0.0.5 and 224.0.0.6 to send Hello and updates. There is also a provision of authentication in the OSPF protocol, which comes in two flavours: basic test and message-digest algorithm 5.

The OSPF employs the Dijkstra algorithm to compute routes by creating the shortest path tree (SPT). In link-state ads, each router displays itself and its links to its neighbours straightforwardly and understandably, allowing OSPF to lay out the network topology using information from the shortest-path tree.

Advantages and Disadvantages of OSPF

There are various advantages and disadvantages of OSPF. Some main advantages and disadvantages of OSPF are as follows:

Advantages

1. OSPF is based on an open standard routing protocol. It is compatible with most routers.
2. It utilizes both incremental updates and trigger updates to offer quick convergence.
3. It supports both IP protocol versions. OSPFv2 and OSPFv3 both support IPv4 and IPv6.
4. It provides a loop-free topology by utilizing the SPF algorithm.

Disadvantages

1. It requires a large amount of data to determine the best route for each location. OSPF uses more RAM than other routing systems to store the data.
2. It is a more difficult protocol to comprehend and learn than other Internet Protocols.
3. It uses the SPF algorithm that needs additional CPU processing to determine the optimum path.

Key differences between EIGRP and OSPF

Here, you will learn the various key differences between EIGRP and OSPF. Some main differences between EIGRP and OSPF are as follows:

1. EIGRP is an advanced distance vector routing technology that employs both incremental and triggered updates. In contrast, the OSPF protocol is a link-state routing protocol that resembles a map and maintains entire data about all routes inside that area.
2. The EIGRP has less convergence time because it utilizes the DUAL algorithm, which selects the best path and an alternate best path. If the selected path fails, it may fall back to the second possible path. In contrast, the OSPF follows a different method. Due to this, it has a longer convergence time.
3. OSPF protocol has greater scalability than EIGRP protocol because EIGRP is complex and vendor-specific, making a transfer from one vendor to another impossible. In contrast, the OSPF protocol is a simple and open standard protocol that enables network scaling.
4. The EIGRP protocol is the only one that supports the unequal path load balancing capability. On the other hand, the OSPF protocol does not support this capability.
5. In terms of backward compatibility with older routers, the EIGRP protocol is a better choice than the OSPF protocol.
6. EIGRP requires less CPU and memory. In contrast, the OSPF protocol requires high memory and CPU.
7. EIGRP protocol is mostly used by medium- to large-sized networks. On the other hand, the OSPF protocol mainly serves larger enterprises in networks.
8. EIGRP protocol lacks a hierarchical structure. In contrast, the OSPF protocol is hierarchically organized.
9. EIGRP protocol utilizes the DUAL distance vector algorithm. In contrast, the OSPF protocol utilizes the Dijkstra link state algorithm.
10. EIGRP protocol administrative distance is 90 for internal and 170 for external. In contrast, the OSPF protocol administrative distance is 110.

Head-to-head comparison between EIGRP and OSPF

Here, you will learn the head-to-head comparisons between EIGRP and OSPF. The main differences between EIGRP and OSPF are as follows:

Conclusion

When you compare the EIGRP and OSPF protocols, you can see that EIGRP is more complicated, whereas OSPF is simpler because it only utilizes cost as a measure. The main distinction between both protocols is that EIGRP exchanges complete routing data just once when neighbouring routes are established and then only tracks modifications. In contrast, the OSPF protocol consistently keeps track of the entire topology database of all the connections in the database.