3.5.d Implement and troubleshoot operations (EIGRP)

3.5.d [i] General operations

ENHANCED INTERIOR GATEWAY ROUTING PROTOCOL

Through the years Cisco’s proprietary (as of this writing) EIGRP has been referred to as a hybrid routing protocol and as an advanced distance vector routing protocol. Arguments can be made in favor of either, however, the fact is EIGRP exhibits behaviors of both link state and distance vector routing protocols no matter the manner to which it is referred.

It’s advantages include:

VLSM support

Rapid convergence because of the Diffusing Update Algorithm

Low CPU overhead

Incremental updates

Scalability

Configuration ease

Manual or automatic route summarization

MD5 authentication

EIGRP employs protocol 88 (http://www.ietf.org/rfc/rfc1700.txt) and uses the multicast address of 224.0.0.10 for hellos and updates (http://www.iana.org/assignments/multicast-addresses/multicast-addresses.xml).