What is the difference between IGRP and BGP?

The Interior Gateway Routing Protocol (IGRP) and Border Gateway Protocol (BGP) are two distinct routing protocols that serve different purposes in network architecture. IGRP operates within autonomous systems, while BGP facilitates routing between different autonomous systems across the internet.

IGRP (Interior Gateway Routing Protocol)

IGRP is a distance-vector routing protocol developed by Cisco Systems in the 1980s for use within autonomous systems. It was designed to overcome the limitations of RIP by supporting larger networks and more sophisticated metrics.

IGRP uses composite metrics including bandwidth, delay, reliability, and load to determine the best path to a destination. Network administrators can adjust the weighting of these metrics to influence route selection. The protocol supports multipath routing, allowing traffic to be distributed across multiple equal-cost paths for load balancing and redundancy.

BGP (Border Gateway Protocol)

BGP is the standard exterior gateway protocol used to exchange routing information between different autonomous systems on the internet. It is a path-vector protocol that focuses on finding any loop-free path to the destination rather than the optimal path based on metrics.

BGP routers, called BGP speakers, maintain routing information in a Routing Information Base (RIB) and share reachability information with their peers. The protocol uses various attributes like AS-path, next-hop, and local preference to make routing decisions and prevent routing loops between autonomous systems.

Key Differences

Conclusion

IGRP and BGP serve complementary roles in network routing. IGRP optimizes routing within autonomous systems using composite metrics, while BGP ensures global internet connectivity by managing routing between different autonomous systems using policy-based decisions.