EIGRP

EIGRP (Enhance Interior Gateway Routing Protocol)

=> It is a hybrid routing protocol that combines the feature of the link state routing protocol and distance vector routing protocol.
=> Administrative distance 90
=> It uses the concept of the autonomous number
=> It is a Cisco proprietary routing protocol.
=> It is a classless routing protocol
=> It support the VLSM
=> Maximum HOP count limit is 255
=> By default it is 100
=> It uses IP protocol 88.

Characteristic of the EIGRP

=> PDM
      1) Protocol dependent Module
          i)  EIGRP provide support for multiple network layer protocol IP, IPX, APPLETALK through PDM.
          ii) For each protocol an independent set of database will be created. I.e. if IP is used then IP/EIGRP database, if IPX then IPX/EIGRP database, if AppleTalk then AppleTalk /EIGRP.

=> Efficient neighbor discovery
      1) Hello packets are exchanged
      2) AS number should be same
      3) Metric should be identical