3.3.m Split horizon…

Split Horizon

loop prevention

rule: a routing interface cannot send routing information out the same interface upon which

it was received

Route Summarization

Routing information can be condensed (summarized) from a longer prefix into a shorter prefix; the routing table is more efficient, reduced, and routing updates are fewer.




Classful routing protocols do not include vlsm in their updates. they are delineated by classful masking.

ex. (rfc 1918) class A class B class C

IP Classless

The ip classless command was introduced into default behavior for ios 12.0. Classful routing protocols, ie. Rip and IGRP discard traffic bound for any unknown subnet of a major network, even with a default route configured. IP classless allows for the use of a default route in this case.