EIGRP (Enhanced Interior Gateway Routing Protocol) is an advanced distance-vector routing protocol developed by Cisco Systems. It is designed to provide efficient and scalable routing within an autonomous system (AS) in a computer network. Here’s an explanation of the concept and workings of EIGRP, along with a working example:
- Concept of EIGRP:
- EIGRP is a hybrid routing protocol that combines the best features of both distance-vector and link-state protocols.
- It uses a metric called “Composite Metric” to calculate the best path for routing and supports load balancing across multiple paths.
- EIGRP operates within a single autonomous system (AS), making it suitable for enterprise networks or large-scale networks.
- EIGRP Features and Mechanisms:
- Fast Convergence: EIGRP uses Diffusing Update Algorithm (DUAL) to achieve quick convergence, minimizing the time taken to adapt to network changes.
- Neighbor Discovery and Maintenance: EIGRP establishes and maintains neighbor relationships to exchange routing information efficiently.
- Partial Updates: EIGRP sends only incremental updates when there are changes in the network, reducing the bandwidth consumption.
- Route Summarization: EIGRP supports route summarization, which helps in reducing the size of the routing tables and improving scalability.
- Load Balancing: EIGRP allows load balancing across multiple paths, maximizing network utilization and providing redundancy.
- EIGRP Working Example:
- Let’s consider a network with three routers: R1, R2, and R3, interconnected as follows:
- R1 is directly connected to networks A and B.
- R2 is directly connected to networks B and C.
- R3 is directly connected to networks A and C.
- Routers R1, R2, and R3 are configured to run EIGRP and exchange routing information.
- EIGRP calculates the best path based on factors like bandwidth, delay, reliability, and load.
- Routers exchange routing updates, and each router builds its routing table to determine the optimal path to reach a destination network.
- EIGRP allows load balancing across multiple paths, so traffic can be distributed among the available links.
- Let’s consider a network with three routers: R1, R2, and R3, interconnected as follows:
interface FastEthernet0/0 ip address 192.168.1.1 255.255.255.0 eigrp 10 ! interface FastEthernet1/0 ip address 10.0.0.1 255.0.0.0 eigrp 10 ! router eigrp 10 network 192.168.1.0 network 10.0.0.0Similar configurations would be applied to routers R2 and R3.
EIGRP is widely used in enterprise networks due to its efficient routing capabilities, fast convergence, and support for load balancing. It provides reliable and scalable routing within an autonomous system, enhancing network performance and availability.
