Foundation Summary

The "Foundation Summary" section of each chapter lists the most important facts from the chapter. Although this section does not list every fact from the chapter that will be on your exam, a well-prepared candidate should, at a minimum, know all the details in each "Foundation Summary" before going to take the exam.

The key features of EIGRP include

  • Neighborship and reliable incremental updates

  • Neighbor discovery and recovery

  • Sophisticated metric

  • DUAL

  • Queries

EIGRP uses five types of packets to communicate:

  • Hello

  • Ack

  • Update

  • Query

  • Reply

EIGRP uses a sophisticated metric that considers bandwidth, load, reliability, and delay. When default constant values are taken into consideration, the equation simplifies to

Additional EIGRP advantages include

  • Incremental Updates

  • Multicast Addressing for Updates

  • Easy Configuration

  • Unequal-Cost Load Sharing

EIGRP builds and maintains three tables:

  • Neighbor table

  • Topology table

  • Routing table

To become a neighbor, the following conditions must be met:

  • The router must hear a Hello packet from a neighbor.

  • The EIGRP autonomous system must be the same.

  • K-values must be the same.