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EIGRP vs OSPF: What’s the Difference & Function in 2023



Enhanced Interior Gateway Routing Protocol (EIGRP) and Open Shortest Path First (OSPF) are two common IGPs (interior gateway protocols) that specify how routers will communicate with each other and distribute information. To put it in simple words, it enables routers to specify their routes and perform well.

These EIGRP vs OSPF protocols are applied in different situations to achieve varied performance on delay, speed, etc. A business needs to pick the right routing protocol for its network.

Routing protocols can adjust according to the changing conditions within the network. Not only that, but it can also detect obstructions as well as offline connections. This is needed to keep a business network accessible.

There exist plenty of other routing protocols, but today, we are going to focus only on EIGRP vs OSPF. In this guide, we will point out the main differences between the two.

EIGRP vs OSPF

The Function of EIGRP

EIGRP is an advanced distance-vector routing protocol designed by Cisco Systems. It helps with configuration and routing decisions on a network. Since it is developed by Cisco, it can be used only on Cisco routers.

This OSI model network layer protocol utilizes measurements to determine the optimal between two layer-3 devices. EIGRP is used to exchange information from one router to the others when they are in the same region.

The good thing about the EIGRP routing protocol is that it can be used in both big and small networks. It is also a hybrid protocol because it utilizes both link-state and distance vector routing protocols.

Another thing about the EIGRP protocol is that it doesn’t use the UDP (User Datagram Protocol) or the TCP (Transmission Control Protocol). This is why it is not identified by a port number.

Instead of TCP, it utilizes RTP (Reliable Transport Protocol) by Cisco. This helps in distributing the updates to all neighboring routers.

EIGRP comprises four main components:

  • Reliable transfer protocol
  • Neighbor discovery and recovery
  • Protocol Dependent Modules, and 
  • DUAL Finite State Machine

The good thing about EIGRP is that it supports fast convergence for changes occurring within the network. It uses the link in a better way through unequal-cost load sharing and ECMP (Equal-Cost Multi-Path). It has support for both IPv6 and IPv4 networks.

The only drawback with this routing protocol is that it can be used only with Cisco routers. However, it is considered the most advanced routing protocol in the industry.

The Function of OSPF

OSPF is a classless routing system that helps VLSM (variable-length subnet masking) as well as discontiguous networks. It uses its algorithm to identify the optimal path between the destination and source routers.

In the case of OSPF, updates are triggered only when a change is detected in the routing table. It is a type of Interior Gateway Protocol (IGP) designed by the IETF (Internet Engineering Task Force). It helps move packets inside a routing domain or an autonomous system. This network layer protocol is recognized by port number 89 and utilizes the AD value 110.

OSPF is designed to work within a single autonomous system. It is commonly used by giant business networks as it has support for CIDR (Classless Inter-Domain Routing) addressing paradigm.

It uses its algorithm to identify the shortest path to a destination router on a network. This type of routing protocol is ideal for managing diverse and large networks. It can recalculate routes as soon as changes occur within the network.

An autonomous system can be split into multiple areas, while OSPF reduces the size of routing traffic. The biggest advantage of this routing protocol is that it supports multipath routing without any extra charges. This allows you to add additional paths with different hops to the TCP stack.

When to Use EIGRP?

EIGRP makes a popular choice among big and small campus networks. It can be deployed in IP (Internet Protocol) networks for data communication.

The thing about EIGRP is that it transmits only incremental updates between routers. This in turn reduces the router’s workload and the amount of data that needs to be transferred.

When to use OSPF?

OSPF makes a suitable choice when your network devices are sourced from different vendors. You can also use it with WLAN technology as it has support for MPLS traffic engineering with Constrained Shortest Path First (CSPF).

It is primarily used for the data center and LAN, but can also occasionally be used in IaaS and WAN environments. The best thing about using OSPF is that complete knowledge of network topology enables routers to calculate routes that meet particular criteria. This comes in handy for traffic engineering purposes, where routes are often constrained to satisfy specific service requirements.

Pros & Cons of EIGRP

PROS

  • Supports both IPV4 and IPV6 networks
  • Advanced distance-vector routing protocol
  • Provides encryption for security
  • Performs well with a multi-address family
  • Helps reduce network traffic

CONS

  • Doesn’t support future applications
  • Only accessible with the CISCO network services

Pros & Cons of OSPF

PROS

  • Allows better load balancing
  • Based on open standard
  • Provides a loop-free topology with an SPF algorithm
  • Suitable for networks of all sizes
  • Can run on most routers

CONS

  • Difficult to configure
  • Requires a lot of information to determine the best route

Difference Between EIGRP vs OSPF

Now that you know the basics of EIGRP vs OSPF, let’s take a look at the main differences between the two routing protocols.

EIGRPOSPF
It is a hybrid routing protocol.It is a link-state routing protocol.
It utilizes a Dual Distance Vector algorithm.It is based on the Dijkstra link state algorithm.
It consumes low CPU power.It consumes a lot of CPU power.
It requires less memory space.It requires a lot of memory space.
It is user-friendly but doesn’t have an auto-summary available.It is difficult to handle.
Routing metrics include reliability, bandwidth, load, and delay.Routing metrics include only load, delay, and bandwidth.
It follows Cisco’s Proprietary standard.It follows IETF Open Standard.

FAQs

Q1. What is the advantage of using EIGRP?

Ans: EIGRP promotes easy transition and has multi-address family support for both IPv6 and IPv4 networks. It has very fast convergence times for changes occurring in the network topology.

Q2. What is routing protocol?

Ans: A routing protocol specifies how routers communicate with each other to distribute information.

Q3. What are the different types of OSPF routers? 

Ans: There are four main types of OSPF routers. These include internal routers; area borders routers, backbone routers, and autonomous routers.

Conclusion

By now the difference between the two routing protocols EIGRP vs OSPF should be clear. EIGRP allows routers in the same autonomous system to share routers while OSPF routers in the same region share a link-state database to describe the topology of the site.

The most thing to remember is that OSPF is based on a link-state routing protocol while EIGRP utilizes a distance vector routing protocol.

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James Burns

I’m James Burns, the founder of Routers Networks. I work as a Network Engineer by profession and as a Network Blogger with the passion to bring you the latest update about networking technology and news.