IGRP (Interior Gateway Routing Protocol) and EIGRP (Enhanced EIGRP) are the two routing protocols used in routing operations. The IGRP is a distance vector interior gateway routing protocols, but the EIGRP incorporates the features of the link state routing with the distance vector routing protocol. There are several differences between the IGRP and EIGRP, priorly IGRP employs a classful routing method while EIGRP is a classless routing protocol. EIGRP provides better support for the vast scale network as compared to IGRP.
Content: IGRP Vs EIGRP
Comparison Chart
| Basis for comparison | IGRP | EIGRP |
|---|---|---|
| Expands to | Interior Gateway Routing Protocol | Enhanced Interior Gateway Routing Protocol |
| Supported addressing technique | Classful | Classless |
| Provided bits for bandwidth and delay | 24 | 32 |
| Least hop count | 255 | 256 |
| Convergence | Slow | Extremely fast |
| Update timers | 90 secs | Only in any alteration |
| Algorithm | Bellman ford | DUAL |
| Administrative distance | 100 | 90 |
| Required bandwidth | More | Less |
Definition of IGRP
IGRP (Interior Gateway Routing Protocol) enables the synchronised routing process between the gateways through exchanging routing information with neighbouring gateways. The routing information contains the gist of the detailed information about the network. There are several gateways involved in solving an optimisation problem. That is the reason, it is known as a distributed algorithm where each gateway is allotted a part of a problem.
The basic implementation of IGRP deals with TCP/IP routing along with various protocols. IGRP protocol is an interior gateway routing protocol which is used within a group of linked networks an either managed by a single entity or group of entities. To connect these set of networks the external gateway protocol is used. IGRP is a successor of RIP (Routing Information Protocol) which contains more features than the RIP. It was devised with enhanced capabilities to handle large and more complicated networks.
The limitation of IGRP is that it experiences the routing loop problem. In order to avoid the routing loop, the IGRP neglects the newly generated data for a period of time when the certain changes take place. Although, the IGRP is easily configurable.
Definition of EIGRP
EIGRP (Enhanced Interior Gateway Routing Protocol) is the improved version of the IGRP which is enabled with many features that are not provided in other protocols. It gives rise to the hybrid routing which is developed by merging the features of the distance vector routing and link state routing. The benefits of EIGRP is that is simple to configure, efficient and secure, but its main advantage is that it assists the classless routing which was not supported by IGRP. The PDM(Protocol Dependent Modules) describes what are the protocol requirements for the network layer and make IGRP compatible with IPv4, IPX and AppleTalk.
- The bandwidth requirement and generated overhead in the EIGRP is smaller than IGRP because it does not send periodic updates; instead, it sends the update only when any changes in path and metric takes place.
- Convergence in EIGRP is faster than other protocols, to achieve this the routers running EIGRP keeps the backup routes to the destination for the uncertain cases. If no backup route present for the destination the router sends the query to the neighbour router asking for the alternate path. This fast convergence is obtained with the help of DUAL (Diffusing Update Algorithm).
- The EIGRP can create summary routes at any point in the network in a short period, instead of depending on the conventional distance vector algorithm where only classful addressing was allowed. Therefore, the route summarization in EIGRP is rapid.
- It also provides the unequal metric load balancing for spreading the traffic flow effectively along the network.
Key Differences Between IGRP and EIGRP
- The IGRP supports classful addressing, while EIGRP permits the use of classless routing.
- For bandwidth and delay, the IGRP is allotted 24 bits. On the other hand, the EIGRP is assigned with 32 bits for the bandwidth and delay.
- The hop count in the IGRP is 255 while it is 256 in the case of EIGRP.
- Convergence in IGRP is slow as compared to EIGRP.
- After every 90 seconds in IGRP, the periodic update is transmitted to the devices. On the contrary, EIGRP sends the update only in case of occurrence of any changes.
- EIGRP follows a DUAL algorithm. As against, IGRP employs bellman ford algorithm.
- The administrative distance of the IGRP is 100. In contrast, the EIGRP routes have the administrative distance of 90.
- Bandwidth requirement in the IGRP is more than the amount needed in the EIGRP.
Conclusion
The routing performance of EIGRP has improved as compared to the IGRP because it has integrated the features of link state routing with the distance vector routing. The problem of the redistribution of the routes is eliminated from the EIGRP, while it present in the IGRP.
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