EIGRP (Enhanced Interior Gateway Routing Protocol) is an advanced distance-vector routing protocol used for automating routing decisions and configuration in computer networks. It uses neighbor discovery processes to dynamically learn about other routers on directly attached networks, reliable transport to guarantee ordered packet delivery, and the DUAL finite state machine to track routes and calculate the best paths. The basic components and packet types of EIGRP, such as hello, update, query, reply and request packets, allow it to share routing information between Cisco routers.
2. The full meaning of EIGRP is Enhanced Interior Gateway
Routing Protocol. EIGRP is an advanced distance-vector routing
protocol that is used on a computer network for automating
routing decisions and configuration.
The protocol was designed by Cisco Systems as a exclusive
protocol, available only on Cisco routers.
EIGRP
3. Basic components of EIGRP
1.Neighbor Discovery/ Recovery: The process that routers use to
dynamically learn of other routers on their directly attached networks.
2.Reliable Transport Protocol: The reliable transport is responsible for
guaranteed, ordered delivery of EIGRP packets to all neighbors.
3.DUAL Finite State Machine: Process for all route calculations. It tracks
all routes advertised by all neighbors.
4.Protocol Dependent Modules: The protocol-dependent modules are
responsible for network layer, protocol-specific requirements.
4. Packet types of EIGRP
• Hello/Acks: Hellos are multicast for neighbor discovery/recovery.
They do not require acknowledgment
• Updates: Updates are used to carry reachability of destinations.
• Queries: Queries are always multicast unless they are sent in
response to a received query.
• Replies: Replies are always sent in response to queries to indicate to
the originator.
• Requests: Request packets are used to get specific information from
one or more neighbors.
