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Chapter 5: Networking Concepts

IT Essentials v7.0

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Chapter 5 - Sections & Objectives

5.1 Network Components and Types• Explain components and types of computer networks.

– Describe the types of networks.– Describe internet connection types.

5.2 Network Protocols, Standards, and Services• Explain networking protocols, standards and services.

– Explain the purpose and characteristics of transport layer protocols.– Explain the significance of application port numbers.– Explain wireless protocols.– Explain network services.

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Chapter 5 - Sections & Objectives

5.3 Network Devices• Explain the purpose of devices on a network.

– Explain basic network devices.– Explain security devices.– Explain other network devices.

5.4 Network Cables• Explain the characteristics of network cables.

– Describe networking tools and their purpose.– Explain the purpose and characteristics of common types of copper network

cables and connectors.– Explain the purpose and characteristics of common types of fiber network

cables and connectors.

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5.1 NETWORK COMPONENTS AND TYPES

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Principles of Networking

Networks are systems that are formed by links. People use different types of networks every day:

• Mail delivery system• Telephone system• Public transportation system• Corporate computer network• The Internet

Computers can be linked by networks to share data and resources. A network can be as simple as two computers connected by a single cable or as

complex as hundreds of computers connected to devices that control the flow of information.

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Computer Networks A computer data network is a collection of hosts connected by networking devices

such as computers, printers, scanners, smartphones, and file and print servers. Resources shared across networks include different types of services, storage

devices, and applications. Network devices link together using a variety of connections:

• Copper cabling • Fiber-optic cabling• Wireless connection

Benefits from networking include:• Fewer peripherals needed • Increased communication capabilities• Avoid file duplication and corruption

• Lower cost licensing• Centralized administration• Conservation of resources

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Computer Network Devices and Components

Host Devices – any device that sends and receives information on the network (computer, printer, etc.)

Intermediary Devices – exist in between host devices Media – component over which the message travels

from source to destination Can you name each device or component shown here?

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Multipurpose Devices

Perform more than one function. More convenient to purchase and configure just one device. Combines the functions of a switch, a router and a wireless access point into one

device. The Linksys E2500 is an example of a multipurpose device. Integrated Service Router combines the functions of:

• Router• Switch• Wireless Access Point

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Types of Networks

LAN (Local Area Network): A group of interconnected computers under one administrative control group that governs the security and access control policies that are in force on the network.

WLAN (Wireless Local Area Network): A group of wireless devices that connect to access points within a specified area. Access points are typically connected to the network using copper cabling.

VLAN (Virtual LAN) – Extends beyond a traditional LAN and groups users based on administratively defined boundaries such as department or floor.

PAN (Personal Area Network): Network that connects devices, such as mice, keyboards, printers, smartphones, and tablets within the range of an individual person. PANs are most often connected with Bluetooth technology. Bluetooth can support up to 7 devices simultaneously.

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Types of Networks

MAN (Metropolitan Area Network): Network that spans across a large campus or a city. Consisting of various buildings interconnected through wireless or fiber optic backbones. A network that spans a city.

WAN (Wide Area Network): Connections of multiple smaller networks such as LANs that are in geographically separated locations. The most common example of a WAN is the Internet. A network that spans a large geographical area.

WMN (wireless mesh network) – Connects multiple wireless access points together to expand the wireless network.

VPN (virtual private network) – A method of connecting to a network such as a company network across an unsecure network.

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Types of Networks

Peer-to-Peer Networks• No dedicated servers• Each computer decides which resources to share• No central administration or security

Client-Server Networks• Server with software installed for client access• Resources controlled by centralized administrator• Secure access to confidential information• A centralized storage• Critical data should be backed up on a regular basis.

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Bandwidth and Latency

Bandwidth is the amount of data that can be transmitted within a fixed time period.

Bandwidth is measured in bits per second and is usually denoted by the following:• bps - bits per second• Kbps - kilobits per second• Mbps - megabits per second • Gbps - gigabits per second

Latency is the amount of time it takes data to travel from source to destination. Data is transmitted in one of three modes:

• Simplex (Unidirectional transmission) is a single, one-way transmission.• Half-duplex allows data to flow in one direction at a time. • Full-duplex allows data to flow in both directions at the same time.

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Brief History of Connection Technologies

Analog telephone access (dialup) – uses an analog modem to transmit data over voice telephone lines to another modem. Also known as a Plain Old Telephone System (POTS). Uses RJ-11 connectors.

ISDN (Integrated Services Digital Network) – more bandwidth than dialup. Can carry voice, video, and data.

Baseband – Carries only one signal over media. Broadband – uses different frequencies to send multiple signals over media. DSL (digital subscriber line) – always on technology that uses phone lines; voice and data

carried on different frequencies; requires a filter on the port that connects to a phone. Cable – Uses a cable modem to connect to a traditional cable TV network; shares the

network with multiple subscribers. Fiber – High bandwidth connection used in backbone networks, large enterprise

environments, large data centers, and now part of some home internet connections.

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Line of Sight Wireless Internet Service

Line of site wireless – always-on technology that uses radio signals sent from a tower to a receiver for connecting to the internet.• Clear path required• Weather affects signal strength and performance

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Satellite

Satellite – broadband technology for remote areas• Uses a satellite dish• Not a good solution for time-sensitive applications like gaming, Voice over

Internet Protocol (VoIP), and video conferencing

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Cellular

Cellular– relies on cell towers to create a network used by cell phones and connectivity to the internet

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Mobile Hotspot and Tethering

Cell phone option that allows another device to connect to the internet using Wi-Fi, Bluetooth, or USB cable• The other device is using the phone’s cellular connection to

connect to the internet• Called tethering or a hotspot

A mobile hotspot is when a cell phone allows Wi-Fi devices to connect and use the mobile data network.

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5.2 NETWORKING PROTOCOLS, STANDARDS, AND SERVICES

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Reference Models

Organizations, such as lEEE, IETF, and ISO, develop open standards for networks so that any client running any operating system can access network resources.

The OSI model and the TCP/IP model are both reference models used to describe the data communication process.

As application data is passed down through the layers, protocol information is added at each level. This is known as the encapsulation process.

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Standards OrganizationsName Type Standards Established

ITU-TITU Telecommunication

Standardization Sector (formerly CCITT)

one of the three Sectors of the International Telecommunication

UnionStandards covering all fields of

telecommunications Became ITU-T in 1992

IEEE Institute of Electrical and Electronics Engineers

A non-profit, technical professional association

Standards for the computer and electronics industry 1884

ISO International Organization for Standardization

A network of the national standards institutes of 157 countries

Promote the development of international standards

agreements1947

IAB Internet Architecture Board A committee; an advisory bodyOversees the technical and

engineering development of the Internet

1979; first named ICCB

IEC International Electrotechnical Commission Global organization

Standards for all electrical, electronic, and related

technologies1906

ANSI American National Standards Institute Private, non-profit organization Seeks to establish consensus

among groups 1918

TIA/EIATelecommunications Industry

Association / Electronic Industries Alliance

Trade associations Standards for voice and data wiring for LANs

After the deregulation of the U.S. telephone industry in

1984

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Ethernet Standards

Ethernet protocols describe the rules that control how communication occurs on an Ethernet network.

IEEE 802.3 Ethernet standard specifies that a network implement the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access control method.

In CSMA/CD, all end stations "listen" to the network wire for clearance to send data. When the end station detects that no other host is transmitting, the end station will attempt to send data. Unfortunately collisions might occur.

Any device connected to a network is considered a host/node.

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Wired and Wireless Standards When Ethernet operates in half-duplex, the IEEE 802.3 standard specifies that a network

implement the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access control method.

The 802.3 standard also specifies cable types for Ethernet including:• 10Base-T• 100Base-TX• 1000Base-T• 10GBase-T

The IEEE 802.11 standard specifies that wireless LANs use Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA).

WLAN standards include 802.11a, 802.11b, 802.11g, 802.11n, and 802.11ac.

When configuring an 802.11 WLAN, use the strongest encryption available. • Since 2006, the strongest encryption has been WPA2.

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Ethernet Technologies

10BASE-T • The ten (10) represents a maximum bandwidth of 10 Mbps• The BASE represents baseband transmission• The T represents twisted-pair cabling.

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Wireless Ethernet Standards

IEEE 802.11 is the standard that specifies connectivity for wireless networks. Wi-Fi (wireless fidelity), refers to the 802.11 family

• 802.11 (the original specification)• 802.11a• 802.11b• 802.11g• 802.11n• 802.11ac• 802.11ad• These protocols specify the frequencies, speeds, and other capabilities of the

different Wi-Fi standards.

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Wireless Ethernet StandardsBandwidth Frequency Range Interoperability

802.11a Up to 54 Mbps 5 GHz band 100 feet (30 meters) Not interoperable with 802.11b, 802.11g, or 802.11n

802.11b Up to 11 Mbps 2.4 GHz band 100 feet (30 meters) Interoperable with 802.11g

802.11g Up to 54 Mbps 2.4 GHz band 100 feet (30 meters) Interoperable with 802.11b

802.11n Up to 540 Mbps 5 GHz and 2.4 GHz bands 164 feet (50 meters) Interoperable with 802.11b and

802.11g

802.11ac Up to 1.3 Gbps 5 GHz band 115 feet (35 meters) Interoperable with 802.11a and 802.11n

802.15.1 Bluetooth Up to 2 Mbps 2.4 GHz band or 5

GHz band 30 feet (10 meters) Not interoperable with any other 802.11

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The TCP/IP Model

Frame of reference used to develop the Internet's protocols. Consists of layers that perform functions necessary to prepare data for

transmission over a network.

Description Protocols

Application Provides network services to user applications

HTTP, HTML, Telnet, FTP, TFTP,

SMTP, DNS

Transport Provides end-to-end management of data and divides data into segments TCP, UDP

InternetProvides connectivity between hosts in the network. IP addressing and routing here.

IP, ICMP, RIP, ARP

Network Access

Where Mac addressing and physical components exist

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The OSI Model

The OSI model is an industry standard framework that is used to divide network communications into seven layers.

Although other models exist, most network vendors today build their products using this framework.

A protocol stack is a system that implements protocol behavior using a series of layers.• Protocol stacks can be implemented either in hardware or software, or in a

combination of both.• Typically, only the lower layers are implemented in hardware, and the higher

layers are implemented in software.

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The OSI ModelLayer Description

Application 7 Responsible for network services to applications

Presentation 6 Transforms data formats to provide a standard interface for the Application layer

Session 5 Establishes, manages and terminates the connections between the local and remote application

Transport 4 Provides reliable transport and flow control across a network

Network 3 Responsible for logical addressing and the domain of routing

Data Link 2 Provides physical addressing and media access procedures

Physical 1 Defines all the electrical and physical specifications for devices

Remember the OSI layers with this mnemonic:"Please Do Not Throw Sausage Pizza Away"

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Compare OSI and TCP/IP Models

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Encapsulation

Process of placing one message format into another format so that the message can be delivered

Receives headers, footers, and other information Five step process:

• Data• Segments• Packets• Frames• Bits

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TCP

Three basic operations of reliability• Numbering and tracking of data segments• Acknowledgment of received data• Retransmitting any unacknowledged data after

a period of time. Required protocol properties:

• Reliable• Acknowledges data• Resends lost data• Delivers ata in sequenced order

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UDP

Very little overhead or data checking Best-effort delivery protocol (unreliable)

• No acknowledgment that the data is received by the destination Required protocol properties:

• Fast• Low overhead• Does not require acknowledgements• Does not resend lost data• Delivers data as it arrives

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Classify Application Port Numbers

World Wide Web Protocols

Port Transport Protocol

Application Protocol

Description

53 TCP, UDP DNS

The Domain Name Service (DNS) protocol finds the IP address associated with a registered Internet domain for Web, Email, and other Internet services. It uses UDP for requests and information transfer between DNS servers. TCP will be used for DNS responses if required.

80 TCP HTTPHypertext Transfer Protocol (HTTP) provides a set of rules for exchanging text, graphic images, sound, video, and other multimedia files on the World Wide Web.

443 TCP, UDP HTTPS The browser uses encryption and authenticates your connection with webserver.

PCs use the source port number to track the data flow of every application.

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Classify Application Port NumbersEmail and Identity Management ProtocolsPort Transport

ProtocolApplication Protocol

Description

25 TCP SMTPSimple Mail Transfer Protocol is used to send email from dents to an email server. It may also be used to relay email messages from source to destination email servers.

110 TCP POP3 Post Office Protocol 3 is used by email clients to retrieve messages from an email server.

143 TCP IMAPInternet Message Access Protocol is used to retrieve email messages from a server. It Is more advanced than POPS and offers a number of advantages.

389 TCP, UDP LDAP

Lightweight Directory Access Protocol is used to maintain user identity directory information that can be shared across networks and systems. It can be used to manage information about users and network resources. It can be used to authenticate users on multiple computers.

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Classify Application Port NumbersRemote Access ProtocolsPort Transport

ProtocolApplication Protocol

Description

22 TCP SSH Secure Shell or Secure Socket Shell provides a strong authentication and encrypted data transport between a client and remote computer. Like Telnet, it provides a command line on the remote computer.

23 TCP Telnet Telnet is an insecure remote access protocol that provides a command line on a remote computer. SSH is preferred for security reasons.

3389 TCP, UDP RDP Remote desktop protocol was developed by Microsoft to provide remote access to the graphical desktop of a remote machine. It is useful for tech support situations, however it should be used with caution because it provides a remote user with complete control of the destination computer.

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Classify Application Port NumbersFile Transport and Management ProtocolsPort Transport

ProtocolApplicationProtocol

Description

20 TCP FTPFile transfer protocol. Used to transfer files between computers. Considered insecure, SSH file transfer protocol (SFTP, TCP port 22) should be used.

21 TCP FTPFTP uses TCP port 21 to establish a connection between the client and FTP server. In order to start a data transfer session.

69 UDP TFTP Trivial File Transfer Protocol utilizes less overhead than FTR.

445 TCP SMB/CIFSServer Message Block or Common Internet File System allow for sharing of files, printers, and other resources between nodes on a network. Related to Samba.

548 TCP, UDP AFP Apple Filing Protocol is a proprietary protocol developed by Apple to enable file services for macOS and classic Mac OS.

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Classify Application Port NumbersNetwork Operations ProtocolsPort Transport

ProtocolApplication Protocol

Description

67/68 UDP DHCP

Dynamic Host Configuration Protocol automatically provides IP addresses to network hosts and provides a way to manage those addresses. The DHCP server uses UDP port 67 and the client host uses UDP port 68.

137-139 UDR TCP NetBIOS (NetBT)

NetBIOS over TCP/IP provides a system through which older computer applications can communicate over large TCP/IP networks. Different NetBT functions use different protocols and ports in this range.

161/162 UDP SNMP Simple Network Management Protocol enables network administrators to monitor network operations from centralized monitoring stations.

427 UDP, TCP SLP Service Location Protocol allows computers and other devices to locate services on a LAN without previous configuration. Usually uses UDP. but can use TCP.

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Bluetooth, NFC, and RFID

Bluetooth• Up to 7 devices to create a PAN• 802.15.1• 2.4 to 2.485 GHz radio frequency range

RFID• Passive or active tags used to identify items

– Passive – rely on RFID reader to activate and read– Active – have a battery to broadcast the ID up to 100 meters

• 125 MHz to 960 MHz radio frequency range NFC (Near Field Communication)

• Devices must be in close proximity to exchange data• Used for payments, printing, public parking, etc.

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Zigbee and Z-Wave

Zigbee• Requires a ZigBee Coordinator to manage client devices connected in a

wireless mesh network.• Devices commonly managed from a cell phone app• IEEE 802.15.4 standard• 868 MHz to 2.4 GHz range up to 20 meters, 65,000

devices, and data speeds up to 250 kb/s Z-Wave

• Proprietary standard, but public version available• 232 devices can connect to a wireless mesh network

with data speeds up to 100 kb/s.

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Cellular Generations

1G/2G – First generation was analog calls only. 2G introduced digital voice, conference calls, and caller ID with speeds less than 9.6 Kb/s

2.5G – supports web browsing, short audio and video clips with speeds up to 237 Kb/s.

3G – full motion video and streaming music at speeds up to 2 Mb/s 4G - IPv6, IP-based voice, gaming services, high quality multimedia at speeds up

to 672 Mb/s LTE (Long Term Evolution) – means it meets the 4G speed standards and

improves connectivity while in motion. Speeds up to 100 Mb/s when mobile and up to 1 Gb/s when stationary.

5G – supports augmented reality (AR), virtual reality (VR), smart homes, smart cars, and data transfer between devices. Download speeds up to 3 Gb/s; upload speeds up to 1.5 Gb/s.

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Client – Server Roles

File Client and Server Web Client and Server Email Client and Server

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DHCP Server

A DCHP server provides IP addressing information.

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DNS Server

A DNS server translates domain names such as cisco.com to an IP address.

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Print Server

A print server • Can control multiple printers• Provides client access to print resources• Allows centralized print job administration• Provides feedback to network clients

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File Server

A file server allows clients to access files using a specific protocol• FTP (File Transfer Protocol)• FTPS (File Transfer Protocol Secure)• SFTP (Secure Shell File Transfer Protocol)• SCP (Secure Copy)

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Web Server

A web server provides web resources using these protocols• Hypertext Transfer Protocol (HTTP)

– TCP port 80• Secure HTTP (HTTPS)

– Secure Sockets Layer (SSL)– Transport Layer Security (TLS)– TCP port 443

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Mail Server

Email messages are stored in databases on mail servers• Client communicates with server in order to reach a different client• Protocol used to send email

– Simple Mail Transfer Protocol (SMTP)• Protocols used to retrieve email

– Post Office Protocol (POP)– Internet Message Access Protocol (IMAP)

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Proxy Server

Proxy servers act on behalf of a client, thus hiding the real internal host Used to cache frequently accessed web pages

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Authentication Server

Authentication, Authorization, and Accounting (AAA) - Allows access to a network device or a particular network

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Syslog Server

Syslog stores network messages sent by networking devices. Keeps a historical record of messages from monitored network devices.

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5.3 BASIC NETWORK DEVICES

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Network Interface Card

A NIC connects computers to wired and/or wireless networks.

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Repeaters, Bridges, and Hubs

Repeaters – Also called extenders because they regenerate the signal so it can be sent further.

Hub – Receives data on one port and sends to all other ports. Bridge – Divides a network into two or more segments and tracks which device is

on each segment.

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Modem

A Modem is an electronic device that connects to the Internet via an ISP. Modem stands for Modulation / Demodulation A modem converts digital data to analog signals for transmission over a phone

line. Uses RJ-11 connectors. Internal modems plug into an expansion slot on the motherboard. External modems connect to a computer through

the serial and USB ports.

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Switches

Ethernet switches record MAC addresses for each device connected to the switch.• Data is sent to a specific device if the MAC address of that device is in the MAC

address table.• Makes forwarding decisions based on the destination MAC address that is

contained in the frame.• Managed switches are used in a company environment and have additional

features.• Unmanaged switches are used in home or a small

business network.• Devices connected to a switch are considered to be

host devices.

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Wireless Access Points

Wireless Access Point (AP) – Primary functions is to provide access to a wireless network for a limited range.

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Routers

Routers connect networks.• Use an IP address to forward traffic to other networks• Can be a multipurpose device (integrated router) that includes switching and

wireless capabilities

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Firewalls

A firewall protects data and devices connected to a network from unauthorized access.

Firewalls use access control lists (ACLs) which are rules used to determine whether data is permitted (allowed through) or denied.

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IDS and IPSAn Intrusion Detection System (IDS) monitors traffic and is a passive system.

An Intrusion Prevention System (IPS) actively monitors traffic and takes action when needed.

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UTMs

Universal Threat Management (UTM) is an all-in-one security appliance (i.e. Cisco ASA 5506-X).

Features are vendor-specific, but could include:• Firewall services• IDS/IPS services• Additional security services against Zero Day, Denial of Service (DoS)

Distributed Denial of Service (DDoS), and spyware• Proxy and email filtering• Network access control• VPN services

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Endpoint Management Server

An endpoint management server monitors end devices such as PCs, laptops, servers, tablets, printers, etc.

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Legacy and Embedded Systems

A legacy system is a device on the network no longer supported, but still in operation.

An embedded system is a device built into something else such as an appliance. Embedded microchips are contained in legacy systems and embedded systems.

Legacy systems and embedded systems could be a security risk.

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Patch Panel

Patch cables are used to make a connection to another patch panel which connects to a different wiring closet, or to a device such as a switch mounted nearby.

A centralized place where network cables attach. It provides a wired or wireless connection between end

devices, switches, and routers and in some cases, can regenerate weak signals.

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Power over Ethernet and Ethernet over Power

Power over Ethernet (PoE) is a standard for providing power to devices such as Access Points, cameras, or IP phones through a cable.

A PoE injector can be connected to a cable and a second cable is used to connect a device that receives power from the injector.

Ethernet over Power (powerline networking) uses existing electrical wiring to create a network.

PoE injector

Network cable

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Cloud-based Network Controller

A cloud-based network controller is a remote device used to manage network devices like access points or switches.

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5.4 NETWORK CABLES

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Network Tools and Descriptions

Wire cutters or side cutters – Trim wires to length

Wire strippers – Removes the out jacket from the cable

Crimper – used to securely attach an RJ-45 connector

Punch down tool – used to terminate wires into termination

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Network Tools and Descriptions

Multimeter –Used to Check electricalcircuits and continuity

Tone Generator –Used to trace wires

Loopback adapter –used to check a port

Cable Tester –Used to test cables

Wi-Fi analyzer –Used to checkWiFi signals

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Cable Types

Cable types used in networking• Twisted-pair• Coaxial• Fiber-optic

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Coaxial Cables

Copper or aluminum wire. Used in cable TV systems and satellite communication

systems. Harder to install, more expensive, and harder to troubleshoot

than twisted-pair cabling. Types of coaxial cable:

• Thicknet or 10Base5 - Coaxial cable that was used in networks and operated at 10 megabits per second with a maximum length of 500 m.

• Thinnet or 10Base2 - Coaxial cable that was used in networks and operated at 10 megabits per second with a maximum length of 185 m.

• RG-59 - Most commonly used for cable television in the US.• RG-6 - Higher quality cable than RG-59 with more bandwidth and less susceptibility to

interference.

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Twisted-Pair Cables

Twisted-pair cabling types• Unshielded twisted-pair (UTP)• Shielded twisted-pair (STP)

UTP• Most common• Four pairs of color-coded wires• Prone to electromagnetic interference (EMI) and radio

frequency interference (RFI) STP

• Better protection against EMI and RFI• More expensive and harder to install

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Cables and Connectors Twisted-pair is the most popular type of cabling used in LANs

today. There are two different twisted-pair wiring schemes: called T568A

and T568B.• The green and orange wires change termination order.• Each wiring scheme defines the pinout, or order of wire

connections, on the end of the cable. Two types of cables can be created:

• A straight-through cable is the most common cable type. The wiring scheme is the same on both sides. Connect UNLIKEdevices.

• A crossover cable uses both wiring schemes. T568A on one end of the cable and T568B on the other end of the same cable. Connect LIKE devices.

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Twisted-Pair Category RatingsCable Type Speed Features

Category 3 100 Mb/s at 100 MHz • The first widely adopted 4 pair UTP that replaced Cat 3 UTP in Ethernet LANs.

• Manufactured with higher standard than Cat 3 to allow for higher data transfer rates.

Category 5e 1 Gb/s at 100 MHz • Manufactured with higher standard than Cat 5 to allow for higher data transfer rates.

• More twists per foot than Cat 5 to better prevent EMI and RFI from outside sources.

Category 6 1 Gb/s at 250 MHz (Cat 6a - 500 MHz)

• Manufactured with higher standard than Cat 5e to allow for higher data transfer rates.

• More twists per foot than Cat 5e to better prevent EMI and RFI from outside sources.

• May have a plastic divider to separate pairs of wires inside the cable to better prevent EMI and RFI.

• Good choice for customers using applications that require large amounts of bandwidth, such as videoconferencing or gaming.

• Cat 6a has better insulation and performance than Cat 6.

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Fiber-Optic Cables

A glass or plastic strand that transmits information using light and is made up of one or more optical fibers enclosed together in a sheath or jacket.

Not affected by electromagnetic or radio frequency interference.

Signals are clearer, can go farther, have greater bandwidth, and provide faster transfer rates than copper cable.

Usually more expensive than copper cabling and the connectors are more costly and harder to assemble.

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Types of Fiber Media

Single-mode fiber (SMF) • Small core• Uses laser technology to send one beam

of light• Long distances (hundreds of kilometers)

Multimode fiber (MMF)• Larger core• Uses LEDs to send light• Light is injected at different angles• Cheaper• Bandwidth up to 10 Gb/s up to 550

meters

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Fiber-Optic Connectors

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Two Types of LAN Topologies

Physical topology is the physical layout of the components on the network.

Logical topologydetermines how the hosts access the medium to communicate across the network.

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Logical Topologies

The two most common types of logical topologies are broadcast and token passing. • Broadcast topology – A host broadcasts a message to all hosts on the same

network segment. There is no order that hosts must follow to transmit data. Messages are sent on a First In, First Out (FIFO). Ethernet is based on this topology.

• Token passing controls network access by passing an electronic token sequentially to each host. When a host receives the token, it can send data on the network. If the host has no data to send, it passes the token to the next host and the process repeats itself.

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LAN Physical Topologies A physical topology defines the way in which computers, printers, and other

devices are connected to a network. Bus

• Each computer connects to a common cable The ends of the cable have a terminator installed to prevent signal reflections and network errors.

• Only one computer can transmit data at a time or frames will collide and be destroyed.

Ring• Hosts are connected in a physical ring or circle.• A special frame, a token, travels around the ring, stopping at each host to allow

data transmission.• There are two types of ring topologies:

– Single-ring and Dual-ring

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LAN Physical Topologies Star

• Has a central connection point : a hub, switch, or router.• Easy to troubleshoot, since each host is connected to the central device with its own wire.

Hierarchical or Extended Star Topology• A star network with an additional networking device connected to the main networking

device to increase the size of the network.• Used for larger networks.

Mesh Topology• Connects all devices to each other.• Used in WANs that interconnect LANs. The Internet is an example of a mesh topology.

Hybrid• A hybrid topology is a combination of two or more basic network topologies, such as a

star-bus, or star-ring topology. The advantage of a hybrid topology is that it can be implemented for a number of different network environments.

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5.5 CHAPTER SUMMARY

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Chapter 5: Network Concepts

• Explain components and types of computer networks.

• Explain networking protocols, standards and services.

• Explain the purpose of devices on a network.

• Explain the characteristics of network cables.

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New Terms and Commands

• PAN• LAN• VLAN• WLAN• WMN• MAN• WAN• VPN• SVI• VLAN• DSL• Cable• Fiber• Line of Sight Wireless

• Satellite• Cellular• Mobile hotspot and tethering• TCP• UDP• Port numbers• 802.11 WLAN protocol• Bluetooth• NFC• RFID• Zigbee• Z-Wave• 1G/2G, 2.5G, 3G, 3.5G, 4G,

LTE, and 5G

• Client-Server roles• DHCP server• DNS server• Print server• File server• Web server• Mail server• Proxy server• Authentication server• Syslog server• NIC• Repeater• Bridge• Hub

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New Terms• Switch• Wireless access point• Router• Firewall• IDS• IPS• UTM• Endpoint management server• Legacy system• Embedded system• Patch panel• Power over Ethernet• Ethernet over Power• Cloud-based network controller

• Wire cutter• Wire stripper• Crimper• Punch down tool• Multimeter• Cable tester• Loopback• Tone generator• Wi-Fi analyzer• Coaxial cable• UTP• STP• Fiber-optic cable• T568A

• T568B• RJ-45 connector• SMF• MMF• ST connector• SC connector• LC connector• Duplex multimode LC

connectors

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