CompTIA® Network+ : Purpose
And Properties Of Routing & Switching
1.4 Explain the purpose and properties
of routing and switching.
Routing is the process of directing the messages generated
at source host towards the destination host over a computer
network. The path may consist of several nodes that forward
the messages (packets) towards the destination. Due to complexity
of the protocols, and user requirements, several routing
protocols have come in to existence. Most popular among
these protocols are 1. RIP v1 and v2, OSPF, EIGRP, and BGP.
Routing protocols should not be confused with routed protocols
such as TCP and UDP. Routed protocols typically carry user
data, whereas routing protocols provide the route information
for user data packets. For most part, routing protocols
are transparent to the end user. Routing protocols may be
classified as below:
Distance Vector: Distance vector routing determines the
direction and distance to any link in the internetwork.
Smaller the metric, better the path. Distance vector routing
is useful for smaller networks. Ex: RIP and IGRP.
Link State: Also known as SPF algorithms, SPF generates
the exact topology of the entire network for route computation
by listening to the first hand information. Bandwidth and
delay are the most widely used metrics. Ex: OSPF and NLSP.
Balanced Hybrid: Balanced Hybrid combines some aspects
of Link State and Distance Vector routing protocols. It
uses distance vectors with more accurate metrics to determine
the best paths to destination networks. Ex: EIGRP
Routing protocols may also be classified as IGP and EGP
IGP(Interiror Gateway Protocols)
Handles routing in one domain (Automonus system)
that is they send routing information between routers
on the same internal network.
These fall in two categories : Distance Vector Protocol
and Link State Protocol
RIP, OSPF are examples of IGP.