Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced and proprietary routing protocol developed for use within autonomous systems (ASes) in computer networks. EIGRP is designed to facilitate the exchange of routing information and determine the best paths for data packet forwarding within a single autonomous system.
Key characteristics of EIGRP include:
- Hybrid Protocol: EIGRP is considered a hybrid routing protocol because it combines features of both distance-vector and link-state protocols. This allows it to offer efficient routing updates while still providing rapid convergence in response to network changes.
- Advanced Metric Calculation: EIGRP uses a sophisticated metric calculation, taking into account factors such as bandwidth, delay, reliability, and load. This enables more precise path selection based on network conditions.
- Incremental Updates: EIGRP sends only incremental updates when there are changes in the network, reducing network traffic and conserving bandwidth.
- Fast Convergence: EIGRP is known for its fast convergence capabilities, allowing routers to quickly adapt to network changes and update their routing tables.
- Support for VLSM and CIDR: EIGRP supports Variable Length Subnet Masking (VLSM) and Classless Inter-Domain Routing (CIDR), making it compatible with modern IP addressing and routing practices.
EIGRP is widely used in networks and provides efficient and scalable routing for various network environments. It may not be supported very well since it was first designed as proprietary protocol by Cisco. For multi-vendor environments, standard routing protocols like OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol) are often preferred.