Distance-Vector Routing

Distance-Vector Routing
Distance-vector routing
is broken down into two parts: distance and vector. Distance is the
measure of how far it is to reach the destination, or the metric to reach the destination. Vector,
or direction, is the direction the packet must travel to reach that destination. This is determined
by the next hop of the path.
Distance-vector routing protocols are known to
route by rumor
. What this means is that a router
will learn routes from its neighbors. Those neighbors learned the routes from their neighbors. It
reminds me of my old high school days when one person would tell another person something and
by the end of the day the entire school knew.
So, what routing protocols are distance-vector routing protocols? The only ones we are concerned
about in this book are Routing Information Protocol (RIP), Interior Gateway Routing
Protocol (IGRP), and Enhanced Interior Gateway Routing Protocol (EIGRP). Because IGRP
and EIGRP are covered in great detail in Chapter 4, “IGRP and EIGRP,” we will not spend
much time on them here.
EIGRP is what is known as an advanced distance-vector routing protocol, or
hybrid. For the BSCI course, Cisco considers EIGRP in the distance-vector routing
protocol class.
Table 1.1 compares the different distance-vector routing protocols covered in this study guide.