Staffsite STMIK PPKIA Pradnya Paramita 0b22b modul 01

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1.2 Understand local area networks (LANs)

1.5 Understand network topologies and access methods

Module 1:

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Agenda

1 Local Area Networks

2 Data Transfer on a LAN

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What is a network?

• _{A network is two devices connected to each other with a}

physical medium, such as wires or radio signals

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What is the purpose of networks?

Networks enhance many aspects of life and business for individuals and organizations, including:

• _{communication and collaboration} • _{sharing information and resources} • _{organizing data}

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How are networks organized?

• _{Networks are organized}

based on their geographic location

• _{A Local Area Network, or}

LAN, is a group of computers or devices that:

• _{are confined to a small geographic area,}

such as a single building

• _{share a common communication}

medium, such as cabled or wireless connections

• _{are connected to a central connecting}

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Network Documentation

• _{Describes, defines, and}

explains the physical and logical method for

connecting devices

• _{The documentation phase}

occurs before a network is built, or when changes are made to the network

• _{Microsoft Visio is a tool that}

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What devices make up LANs?

Hub Switch

Router

Laptops Phones

Desktop PCs

Servers _Tablets

HOSTS CENTRAL

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What are hosts?

• _{Desktop PCs, laptops, cell phones, servers, routers and so on} • _{A host can be any device that has an}_{IP address}_{– an address}

used to send and receive data in a network

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What are central connecting devices?

• _{Hubs, switches, and routers act as central connecting devices} • _{Central connecting devices are responsible for:}

• _{connecting hosts} • _{transmitting data}

• _{Different central connecting devices perform these functions in}

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How do hubs function?

• _{Hosts send data to a hub}

• _{The hub then broadcasts that}

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How do switches function?

• _{Hosts send data to a switch} • _{Switches direct data to its}

intended destination

• _{Unlike hubs, switches can}

send and receive data simultaneously

• _{Switches are the most}

common device used to

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How do routers function?

• _{Routers are at the edge of}

LANs

• _{They act as a gateway to other}

networks

• _{Routers allow communication}

between hosts on different networks

Internet

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What are central connecting devices?

• _{Computers have}_{network adapters}_{, also}

known as Network Interface Cards (NICs), that allow them to connect to networks

• _{NICs via wires or wireless signals}

• _{Wired adapters feature an}_{RJ45 port}

• _{Wireless adapters feature an antenna and connect to}

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Ethernet Cables

• _{Ethernet cables are made of}

copper wires

• _{Transmit data in the form of}

electrical pulses

• _{Wireless connections rely on different}

technologies

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Ethernet Cables

• _{WAPs provide a central point of}

access for devices that want to connect to a Local Area Network (LAN)

• _{Wireless networks can consist of}

many types of devices other than traditional PCs:

• _{Smart phones} • _PDAs

• _{Tablet computers} • _{Micro computers}

• _{PCs and laptops equipped with wireless network}

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Serial Data Transfer

• _{Transfer of one bit at a time} • _{Data can travel in a single bit}

stream in both directions

• _{Depends on type of connection}

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How fast does data travel?

• _A_{data transfer rate}_{is the maximum}_{bits per second}

(bps) that can be transmitted over a network

• _{Signified with a lowercase b}

• _{The lowercase b differentiates bits from bytes}

10

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Data transfer in LANs - Sending

Before data is transferred, it has to go through the following

process:

1. Large chunks of data are broken into

segments

2. Addressing information is added to

each segment, making it a packet

3. Packets then travel to the network

adapter, where a little more

information is added and they become Ethernet frames.

4. Each frame is then broken into a data

stream of bits – 0s and 1s – that travel over physical media

Frame Packet

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Data transfer in LANs - Receiving

When data is received, it goes through the process in reverse:

1. The receiving computer reassembles

the bits into an Ethernet frame

2. It removes the frame information, and

checks the packet information to make sure it was the intended

recipient

3. The packet information is then

stripped, and the data segment is reassembled into the file that we click on in Windows Explorer

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How does data know where to go?

Most every computer and many other devices have an Internet Protocol (IP) address

• _{Uniquely identifies a device and its associated network}

A typical example of an IPv4 address would be 192.168.1.1 Every IP address is broken down into two parts by a subnet mask

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Subnet Mask

• _{A group of four numbers that define a computer’s network}

• _NOTE:_{All of the 255s in a subnet mask collectively refer to}

the network portion, whereas the 0s refer to the host portion

Type of

Address First Octet Second Octet Third Octet Fourth Octet

IP Address 192 168 1 1

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Wired LANs (WLANs)

Hosts, such as PCs or laptops, are connected to central

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Wired LANs (WLANs)

• _{Hosts connect to networks}

through WAPs

• _{To connect to a WAP, a}

device must have a wireless network adapter

• _{In larger WLANs, the WAP has}

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Virtual LANs (VLANs)

With VLANs, devices in a LAN are grouped based on their function

Implemented to:

• _{organize networks} • _{enhance performance} • _{increase security}

Physical location of devices does not matter

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Perimeter Networks

• _{Perimeter networks, or}

demilitarized zones

(DMZs), are small LANs that

are set up outside of an organization’s LAN

• _{DMZs typically consist of}

servers that provide services, like web hosting or email

• _{This setup allows users}

outside of an organization’s LAN to access the servers, but not the organization’s LAN

Internet

perimeter network

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Summary

1 Local Area Networks

2 Data Transfer on a LAN

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