- EIGRP is a Cisco proprietary routing protocol used for dynamic routing within an autonomous system (AS).
- It is an advanced distance-vector routing protocol that uses features like Diffusing Update Algorithm (DUAL) for fast convergence.
- EIGRP supports classless routing and is compatible with IPv4 and IPv6.
- Advanced Metric Calculation: EIGRP uses bandwidth, delay, reliability, load, and MTU values to calculate the metric for path selection.
- Fast Convergence: EIGRP minimizes convergence time by using partial updates and maintaining a topology table.
- VLSM Support: EIGRP supports Variable Length Subnet Masking (VLSM) to efficiently use IP address space.
- Route Summarization: EIGRP allows summarization of networks to reduce routing table size and optimize routing.
- Load Balancing: EIGRP supports equal-cost load balancing, distributing traffic across multiple paths with the same metric.
- Neighbor Discovery: EIGRP uses Hello packets to discover and maintain neighbor relationships.
- Authentication: EIGRP supports authentication mechanisms to ensure secure routing exchanges.
- Enable EIGRP:
router eigrp <AS number>
- Add Networks:
network <network-address> <wildcard-mask>
- Enable Auto Summary:
- Configure Metrics:
metric weights <k1> <k2> <k3> <k4> <k5>
- Enable Load Balancing:
- Configure Authentication:
- Enable Authentication:
authentication mode <mode>
- Set Authentication Key:
key chain <chain-name>
- Assign Key to Interface:
interface <interface> authentication key-chain <chain-name>
- Enable Authentication:
- Show Neighbors:
show ip eigrp neighbors
- Show Topology Table:
show ip eigrp topology
- Show Routing Table:
show ip route eigrp
- Show EIGRP Interfaces:
show ip protocols
EIGRP Message Types:
- Hello: Used for neighbor discovery and maintaining neighbor relationships.
- Update: Conveys routing information and updates to neighboring routers.
- Query: Sent when a router needs more information about a route from its neighbors.
- Reply: Provides a response to a query message.
- ACK: Acknowledgment message confirming receipt of EIGRP packets.
EIGRP Metric Components:
- EIGRP uses the following metric components for path selection:
- Bandwidth: The bandwidth of the outgoing interface.
- Delay: The cumulative delay along the path.
- Reliability: The reliability of the path.
- Load: The current load on the path.
- MTU: The Maximum Transmission Unit of the path.
This cheatsheet provides a quick reference for EIGRP configuration, verification, and key concepts. It can help you with basic EIGRP configuration tasks and understanding the protocol’s features and operations.