Networking Essentials is a first-year business of the IT Factory explaining the basics of networks/infrastructure. All chapters are quoted together with, for example, the OSI Model.
Chapter 1: Explore the network
Network has no boundary and supports the way we:
- Learn
- Communicate
- Work
- Play
Client request and display information
Servers provide information to other devices on the network
Computer can be both server and client at the same time
Peer-to-peer
Advantages:
Easy to set up
Less complexity
Lower cost since network devices and dedicated servers may not be required
Can be used for simple tasks such as transferring files and sharing printers
Disadvantages:
No centralized administration
Not as secure
Not scalable
All devices may act as both clients and servers which can slow their performance
Components of network
3 categories of network components:
Devices
o End devices
Either the source or destination of a message
Computer, laptop, …
o Intermediary network devices
Connect multiple individual networks to form an internetwork
Connect the individual end devices to the network
Ensure data flows across the network
Provide connectivity
Examples:
Network access devices (switches; wireless access points)
Internetworking devices (routers)
Security devices (firewalls)
Media
o Network media
Provide the pathway for data transmission
Interconnect devices
3 types of media: wireless, LAN, WAN
Services
NIC = network interface card
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,Physical port = a connector or outlet on a networking device
Interface = specialized ports on an internetworking device that connect to individual networks
Topology diagrams
Physical topology diagrams = identify the physical location of intermediary devices, configured ports, and cable
installation
Logical topology diagrams = identify devices, ports, and IP addressing scheme
LAN & WAN
Local Area Networks (LAN): a network infrastructure that provides access to
users and end devices in a small geographical area
Interconnects end devices in a limited area
Administrated by a single organization
Provide high speed bandwidth to internal devices
Wide Area Network (WAN): a network infrastructure that provides access to
other networks over a wide geographical area
Interconnects LAN
Administrated by multiple service providers
Provide slower speed links between LANs
Others:
Metropolitan Area Network (MAN)
Wireless LAN (WLAN)
Storage Area Network (SAN)
Internet, intranet and extranet
Internet = worldwide collection of interconnected networks, not owned by any individual or group
Internet access technologies:
Internet service provider (ISP)
Broadband cable
Broadband digital subscriber line (DSL)
Wireless WANs
Mobile services
Business DSL
Leased lines
Metro ethernet
Kabelmodem
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, o Een special type modem dat wordt gebruikt om data over het kabeltelevisienetwerk (bestaande uit
coax en glasvezel) te transporteren
Types of internet connections: home and small office, business
Snelheid internetconnectie:
Bandbreedte = de maximale hoeveelheid informatie die van 1 plaats naar een andere plaats over het
netwerk kan stromen in een gegeven tijdsinterval. Deze wordt uitgedrukt in bits per seconde.
Throughput (werkelijke bandbreedte afhankelijk van aantal gebruikers op het netwerk) = de hoeveelheid
informatie (= data + overhead) die over het netwerk werd doorgestuurd binnen een bepaald tijdsinterval.
Goodput = meet de werkelijke data-overdracht over een netwerk gedurende een bepaald tijdsinterval
Vertraging = de minimale tijd die een netwerk nodig heeft om de kleinst mogelijke hoeveelheid data te versturen.
Converged networks
traditional separate networks = each network with its own rules
Converging network = capable of delivering data, voice and video over the same network infrastructure
4 basic characteristics of network architecture:
Fault tolerance
o Redundant connections allow for alternative paths if a device or a link fails. The user experience is
unaffected
Scalability
o Additional users and whole networks can be connected to the internet without degrading
performance for existing users
Quality of service (QoS)
o All communication has some access to the media, but higher priority communication has a greater
percentage of the packets
Security
o Administrators can protect the network with software and hardware security and by preventing
physical access to network devices
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, Networking technologies for the Home
Smart home
Powerline networking = uses existing electrical wiring to connect devices
Wireless broadband:
wireless internet service provider (WISP)
wireless broadband service using cellular technology (4G)
Security
Threats examples Solutions examples
Viruses, worms and Trojan horses Antivirus and antispyware
Spyware and adware Firewall filtering
Zero-day attacks (zero-hour attacks) Dedicated firewall systems
Hacker attacks Access control lists (ACL)
Denial of service attacks Intrusion prevention systems (IPS)
Data interception and theft Virtual private networks (VPNs)
Identity theft
Data center = a facility used to house computer systems and associated components including:
redundant data communications connections
high-speed virtual servers
redundant storga systems (typically uses SAN technology)
redundant or backup power supplies
environmental controls (air conditioning, fire suppression)
security devices
data center Google: bekabeling uitgevoerd in Fiber en hebben een warmtenet
Chapter 2: configure a network
operating system
Cisco IOS (Internetworking Operation System)
Network operating system = enables device hardware to function and provide an interface for users to interact.
Kernel = the portion of the operating system that interacts directly with computer hardware
Shell = the portion that interfaces with applications and the user
The user can interact with the shell using a command line interface (CLI, text-based environment) or graphical user
interface (GUI)
CLI is less resource intensive and very stable when compared to a GUI
Operating systems:
pc open source (OC) allows users to interact with the computer
user-computer interaction in PC operating systems (OS) are often done via mouse, keyboard and monitor
cisco IOS = operating system
cisco IOS allows users to interact with Cisco devices
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