EIGRP vs OSPF: Simplified Comparison in a Table Format

Introduction

Interior gateway routing protocols (IGPs) are the core of computer networking. Without them, we can’t connect devices. Different IGPs exist in the industry, but EIGRP and OSPF dominate in usage. Their functionality is connecting devices, but their ways of connecting devices differ. When considering EIGRP vs OSPF, both routing protocols have their own strengths and specific use cases. However, it depends on the design of our company network to determine which one we should choose.

Understanding the Basics

EIGRP:

EIGRP is an IGP routing protocol that is specially used with Cisco devices because it is a Cisco proprietary protocol. It was designed to combine the best features of distance vector and link-state routing protocols. EIGR chooses the best path based on a composite metric. Normally, medium—to large enterprises use EIGRP for connectivity.

OSPF:

OSPF is an open-standard routing protocol. Large enterprises widely use OSPF in their networks because of robustness, scalability, complex network design, and fast convergence. OSPF uses a hierarchical design for its connectivity. It works within an autonomous system.

Difference between EIGRP vs OSPF

FeaturesEIGRPOSPF
Protocol TypeDual (Diffuse update algorithm)Open Standard
Algorithm usedDual algorithmThe shortest path first algorithm
DesignFlat designIt uses cost as its metric, which is based on link bandwidth
Metric CalculationIt consumes low CPU and memory utilizationUses composite metrics to choose the best path
SummarizationAutomatic summarization is enabled by default but can be configured manually. A summary can be configured per interface.Dual Algorithm
Resource UtilizationAs compared to EIGRP, it has a slow convergence time in large enterprises due to its SPF recalculationIts CPU and memory utilization is high as compared to EIGRP
Convergence TimeIt has a simple configurationDue to its hierarchical nature, it requires careful planning of areas and interface
Configuration ComplexityIt has greater scalability in small to medium networks but less in large networks.It already has backup routes in its topology table, due to which its convergence time is high
ScalabilityOSPF discovers network through the use of hello packets and LSAsOSPF is ideal for large, multi-vendor, and complex network environments
Network DiscoveryIt supports both equal and unequal-cost load balancingIt sends partial updates when a route goes down
Load BalancingIt discovers its neighbor through hello packets and maintains the neighbor’s relationshipOSPF supports only equal-cost load balancing
Multicast address224.0.0.10224.0.0.5 and 224.0.0.6
Administrative DistanceIt has no backup routes, so it recalculates routes when a failure occurs.110 for all routes
Backup routesFeasible successor or backup routes are stored in the topology tableOSPF sends flooding of LSAs to all routers in an area in case of link failures
UpdatesOSPF sends flooding of LSAs to all routers in an area in case of link failuresOSPF sends flooding of LSAs to all routers in an area, in case of link failures
Bandwidth UtilizationThe Dead Interval for EIGRP is 15 seconds in LAN and 30 seconds for WanIt Requires more bandwidth due to the initial topology discovery phase and frequent network changes
Hello Timer IntervalEIGRP sends hello packets after 5 seconds for LAN, 60 seconds for WANThe Dead Interval for EIGRP is 15 seconds in LAN, and 30 seconds for Wan
Dead Time IntervalAs it sends partial updates, it consumes less bandwidthIt is 40 and 120, respectively
EIGRP vs OSPF

Configuration of EIGRP and OSPF

EIGRP Configuration:

First, we will take three routers and configure EIGRP on them. Our aim is to explore how to configure EIGRP in the network. The lab consists of three routers: R1, R2, and R3. We will configure the basic IPs and then run the EIGRP protocol on them.

R1 basic IP configuration and EIGRP protocol running

R2 configuration

Similarly, configure R3,

The EIGRP protocol configuration is very easy. It is just like advertising RIP routes in the RIP protocol. The digit 1 represents EIGRP’s AS number, which should be the same on all routers. But if we configure a different AS number on every router, then you will have to redistribute all routers among each other.

Another command, which shows the IP protocol, will tell you the essential configuration of the EIGRP protocol.

Finally, check the routing table and then ping the remote routes.

OSPF Configuration:

The lab has three routers: R1, R2, and R3. Similarly, all three routers have three areas configured.

The lab has three routers: R1, R2, and R3. Similarly, all three routers have three areas configured. We will configure Area 0 on R2’s Loopback interface, Area 1 on R2 and R3, while area 2 between R2 and R3.

R1 Basic IP and OSPF configuration,

Configuratio of R2;

Also configure R3’s conflagration;

Run the show ip route command, and then ping R1 and R2 loopback interfaces from R2 for connectivity.

We have configured OSPF on all three routers correctly because it pings each router from R2.

Similarly, run another useful command, “show ip protocol’,

Check the observation from the highlighted section in the screenshot. The digit with “ospf 1” is a local value, which doesn’t affect the entire network, as in the case of EIGRP. It is not necessary in the OSPF protocol to write the same value on all routers. However, it is mandatory in EIGRP to run the same AS number on all the routers. Otherwise, they will not communicate with each other unless you configure redistribution. This highlights a key difference in the debate of EIGRP vs OSPF.

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