Difference Between IGRP and EIGRP

The routing operations play a pivotal role in deciding the path and the sequence of the operation that is being performed. It can establish an optimum balance between the operations. Various protocols guide the operations in routing. The two most common and important routing protocols are IGRP and EIGRP.


The main difference between IGRP and EIGRP is that IGRP is a routing technique that is classful while EIGRP is a classless routing technique. The rate of convergence in IGRP is slow while the rate of convergence in EIGRP is extremely fast. IGRP requires longer bandwidth while EIGRP requires a shorter bandwidth comparatively.


IGRP is a routing protocol that functions over distance yet interiors of a closely connected network. IGRP has an algorithm called Bellman-Ford. It contains a list of the information in the network. The protocol deals with routing like TCP and IP.

On the other hand, EIGRP is a routing protocol that functions over a link-state vector routing protocol as well as link distance vector routing. It has advanced features and techniques. The support that EIGRP provides is best for huge-scale networks that are complex and require high functioning capabilities. It is a secure and configurable protocol.

Comparison Table between IGRP and EIGRP

Parameters of Comparison IGRP EIGRP
Full form Interior Gateway Routing Protocol Enhanced Interior Gateway Routing Protocol
Type Distance vector routing protocol Link state vector routing protocol as well as link distance vector routing protocol
Convergence rate It has a slow rate of convergenceIt has a fast rate of convergence
Algorithm The algorithm used in IGRP is Bellman-Ford The algorithm used in EIGRP is Dual Algorithm
Delay (in bits) The delay in IGRP is about 24 bits The delay in EIGRP is about 32 bits

What is IGRP?

IGRP stands for Interior Gateway Routing Protocol. It is a type of routing protocol that can function over a distance vector. The algorithm used in IGRP is Bellman-Ford. The IGRP method has the least hop count of 255. It is efficient in synchronizing the routing process between gateways that are exchanging routing information with other neighboring gateways.

The routing information in IGRP consists of a list of detailed precise information about the network. Since there are numerous gateways involved to solve the problem in optimization, IGRP has its algorithm distributed which can tackle the problem through the allotted gateway. IGRP has the basic routing of TCP or IP under several protocols.

As the name suggests, it is an Interior protocol and is used within a group of closely related networks. The network can be managed by an individual entity or a group of entities. IGRP is also considered as a successor of Routing Information Protocol (RIP). The capabilities of IGRP are advanced and can handle diverse, huge, and complex networks.

Apart from the several advantages, there are many limitations and drawbacks of IGRP. Various problems arise in the routing loop and to minimize these routing loop problems, the entire newly generated data is neglected for a period. The neglect continues until all the changes take place. IGRP is easily configurable which may not be desirable for many networks.

What is EIGRP?

EIGRP stands for Enhanced Interior Gateway Routing Protocol. It is a type of routing protocol. It acts as a link-state routing protocol and also serves as a vector routing protocol. EIGRP caters efficient support for the huge scale network. It is an improved version of the existing IGRP. It provides advanced features which are not available in most other protocols.

EIGRP gives rise to a hybrid routing. This kind of routing is developed by merging the distance vector routing and link-state routing features. EIGRP has several advantages like it is easy to configure, and provides security in the networks. The features are efficient and functional. EIGRP is supported by the classless routing technique.

EIGRP generates smaller overhead and functions within a small bandwidth. It does not send any periodic updates and only updates when there is a change in metric or path. It is also the fastest protocol in terms of convergence rate because of DUAL (Diffusing Update Algorithm). It also provides backup routes to the destinations in any uncertain case.

EIGRP has a rapid route summarization and has the potential to create a summary route at any point, within a short span, in the network. The metric for traffic flow in EIGRP follows unequal metric load balancing and spreads traffic across the network effectively. The bandwidth and delay in EIGRP are 32 bits. The performance is better than most other protocols.

Main Differences Between IGRP and EIGRP

  1. The IGRP has the least hop count of 255 while the EIGRP has the least hop count of 256.
  2. The routing technique in IGRP is supported by classful while the routing technique in EIGRP is supported by classless.
  3. The timers in IGRP update in 90 secs while the timers in EIGRP updates only in any alteration.
  4. The administrative distance covered by IGRP is 100 while the administrative distance covered by EIGRP is 90.
  5. The bandwidth required in IGRP is more while the bandwidth required in EIGRP is comparatively less.


Routing protocols specify the communication nature and type between the network of routers. The information distribution is controlled between the selected routes by the routing protocols. IGRP and EIGRP are the common gateway routing protocols in routing operations. They act as an optimal path to deliver the information and sets rules between the source and the destination.

Both protocols have distinct differences in terms of performance, features, algorithm, timers, bandwidth, and other essential requirements. IGRP is a traditional protocol while EIGRP is the improvised version of IGRP. IGRP has several problems in routing loop and redistribution of routes which is eliminated and absent in EIGRP. The choice of the protocols is made depending upon the need of the network.


  1. https://citeseerx.ist.psu.edu/viewdoc/download?doi=
  2. https://citeseerx.ist.psu.edu/viewdoc/download?doi=
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