Difference between IGRP and EIGRP

Interior Gateway Routing Protocol (IGRP):
Interior Gateway Routing Protocol is the routing protocol. It is also a distance vector routing protocol. In this, Bellman ford algorithm is used. The least hop count in IGRP is 255. 

Enhanced Interior Gateway Routing Protocol (EIGRP):
Enhanced Interior Gateway Routing Protocol is routing protocol like Interior Gateway Routing Protocol. It is the link state routing protocol as well as vector routing protocol. 

The main difference between the IGRP and EIGRP is that, Interior Gateway Routing Protocol is Classful routing technique, while Enhanced Interior Gateway Routing Protocol is a classless routing technique. 

Difference between IGRP and EIGRP:

S. No.	IGRP	EIGRP
1.	IGRP stands for Interior Gateway Routing Protocol.	EIGRP stands for Enhanced Interior Gateway Routing Protocol.
2.	Interior Gateway Routing Protocol is Classful routing technique.	While Enhanced Interior Gateway Routing Protocol is a classless routing technique.
3.	IGRP is a slow convergence.	While it is a fast convergence.
4.	In IGRP, Bellman ford algorithm is used.	While in this, DUAL (Diffusing Update Algorithm) is used.
5.	IGRP needs more or high bandwidth.	While EIGRP needs low or less bandwidth.
6.	The least hop count in IGRP is 255.	While the least hop count in EIGRP is 256.
7.	It provides 24 bits for bandwidth and delay.	While it provides 32 bits for bandwidth and delay.
8.	It requires administrative distance of 100.	It requires administrative distance of 90.
9.	It only supports multi-part routing but not areas or tables.	Neighbor tables, topology tables and routing tables are used for routing.
10.	The symbol “I” is used in the routing table to represent IGRP.	The symbol “D” is used in the routing table to represent EIGRP.
11.	It does not support Variable Length Subnet Mask (VLSM).	It supports Variable Length Subnet Mask (VLSM).