Information Technology

There are loads of reasons in favor of subnetting, including the following benefits:
Reduced Network Traffic We all appreciate less traffic of any kind. With networks, it’s no
different. Without trusty routers, packet traffic could grind the entire network down to a
near standstill. With routers, most traffic will stay on the local network; only packets destined
for other networks will pass through the router. Routers create broadcast domains.
The more broadcast domains you create, the smaller the broadcast domains and the less
network traffic on each network segment.
Optimized Network Performance This is the very cool reward you get when you reduce
network traffic!
Simplified Management It’s easier to identify and isolate network problems in a group of
smaller connected networks than within one gigantic network.
Facilitated Spanning of Large Geographical Distances Because WAN links are considerably
slower and more expensive than LAN links, a single large network that spans long
distances can create problems in every area previously listed. Connecting multiple smaller
networks makes the system more efficient.

Subnetting Basics:

“IP Addressing,” you learned how to defi ne and fi nd the valid host ranges
used in a Class A, Class B, or Class C network address by turning the host bits all off and
then all on. This is very good, but here’s the catch: You were defi ning only one network.
What would happen if you wanted to take one network address range and create six networks
from it? You would have to do something called subnetting , because that’s what
allows you to take one larger network and break it into a bunch of smaller networks.

Network Address This is the designation used in routing to send packets to a remote
network—for example, 10.0.0.0, 172.16.0.0, and 192.168.10.0.
IP Address A logical address used to defi ne a single host; however, IP addresses can be used
to reference many or all hosts as well. If you see something written as just IP, it is referring to
IPv4. IPv6 will always be written as IPv6.
Broadcast Address The broadcast address is used by applications and hosts to send
information to all hosts on a network. Examples include 255.255.255.255, which designates
all networks and all hosts; 172.16.255.255, which specifi es all subnets and hosts
on network 172.16.0.0; and 10.255.255.255, which broadcasts to all subnets and hosts on
network 10.0.0.0.

10.0.0.0

IP Terminology:

You’ll learn several important terms vital to your understanding of
the Internet Protocol. Here are a few to get you started:
Bit A bit is one binary digit, either a 1 or a 0.
Byte A byte is 7 or 8 bits, depending on whether parity is used. For the rest here,
always assume a byte is 8 bits.
Octet An octet, made up of 8 bits, is just an ordinary 8-bit binary number. here,
the terms byte and octet are completely interchangeable, and they are typically displayed in
decimal up to 255.

MDF/IDF

The main distribution frame (MDF) is a wiring point that’s generally used as a reference point
for telephone lines. It’s also considered the WAN termination point. It’s installed in the build ing as part of the prewiring, and the internal lines are connected to it. After that, all that’s left
is to connect the external (telephone company) lines to the other side to complete the circuit.
Often, another wire frame called an intermediate distribution frame (IDF) is located in an
equipment or telecommunications room. It’s connected to the MDF and is used to provide
greater flexibility for the distribution of all the communications lines to the building. It’s typi cally a sturdy metal rack designed to hold the bulk of cables coming from all over the building!

Small Form Factor Fiber-Optic Connectors:

Another cool fiber-optic connector is the small form factor (SFF) connector, which
allows more fiber-optic terminations in the same amount of space than its standard-sized
counterparts. The two most popular versions are the mechanical transfer registered jack
(MT-RJ or MTRJ), designed by AMP, and the Local Connector (LC), designed by Lucent.

Fiber-Optic Transceivers:

Fiber-optic transceivers can be either unidirectional (simplex) or bidirectional (duplex).
Let’s look at both standards:
Bidirectional Bidirectional communication is possible if the cable used is following the
EEE 802.3ah 1000BASE-BX10-D and 1000BASE-BX10-U standards. The communication
over a single strand of fiber is achieved by separating the transmission wavelength of the
two devices.

Fiber Distribution Panel:

Fiber distribution panels (FDP) are termination and distribution systems for fiber optic
cable facilities. It consists of a cable management tray and a splice drawer. They are
designed for central offices, remote offices and LANs using fiber optic facilities.

Fiber Optic Connector

Fiber-Optic Connectors:

A whole bunch of different types of connectors are available to use with fiber-optic cables,
but the two most popular are the straight tip (ST) and the subscriber (or square) connector
(SC). The ST fiber-optic connector (developed by AT&T) is one of the most widely used
fiber-optic connectors; it uses a BNC attachment mechanism similar to Thinnet’s that
makes connections and disconnections fairly frustration free. In fact, this is the feature
that makes this connector so popular

There’s one other type of copper connector called the RJ-48c, which looks exactly like
an RJ-45 connector. This plug is very similar to the RJ-45 in that it has four wire pairs, but
they are wired differently and used for different circumstances.
RJ-45 is mainly used in LANs with short distances (typically up to 100 meters), where
the RJ-48c wiring type would be used with a T1 connection, which is a long-distance wide

area network (WAN). In addition, to protect the signal in an RJ-48c, the wires are typically
shielded, whereas the RJ-45 uses unshielded wiring