Network Theories (Chapter 5) Flashcards
Network
A systems ability to connect, share and communicate with other systems.
- provides services and resources
Types of Networks
PAN - Personal Area Network
LAN - Local Area Network
WLAN - Wireless Local Area Network
MAN - Metropolitan Area Network
WAN - Wide Area Network, made up of small networks
SAN - Storage Area Network
Ethernet Standards
Cat 5 - 100Mbps @ 100m 1000BASE-XT
Cat 5e - 1Gbps @ 100m 1000BASE-T
Cat 6 - 1Gbps @ 100m 1000BASE-T
Cat 6 - 10Gbps @ 50m 10GBASE-T
Cat 6A - 10Gbps @ 100m 10GBASE-T
SOHO
Small Office/ Home Office is a network using single internet appliances as access points (Ethernet Switch, Internet Router)
Unshielded Twisted Pair (UTP)
Most common type of ethernet cable with 4 twisted pairs of wires that carry equal signals.
- easily workable
- protection against Crosstalk & EMI
Shielded Twisted Pair (STP)
Each twisted copper pair is covered in a conductive metal foil to protect against Crosstalk and EMI. metal foil makes cable harder to work with
Plenum Cables
A fire safe ethernet cables that is graded to be used in ventilation ducts, which does not produce any harmful gases when heated.
- PVC jacket
- fire rated cable
- not flexible
- CMP/MMP rate
Patch Panel
A pass through devices where network cables form a computer gets hard wired into the back of the devices and then rewired from the front into a switch
Switch
a device that connects other devices together on a network
- forwards data based on data link address (MAC)
- up to 48 ports
- can provide Power over Ethernet (PoE)
- L-3 switches have build in routers capabilities
Fiber Optic
A cable that sends data via light that prevent interference and signal attenuation
Single Mode Fiber (SMF)
- Long range (100Km)
- small core = long wavelength
- more expensive than MMF
- laser light source
Multi-Mode Fiber (MMF)
- Short range (2Km)
- Larger core = shorter wavelength
- Less expensive than SMF
- LED light source
Coaxial Cable
Used for carrying cable TV signals as well as broadband cable internet
-Copper cable (No twisted pair)
- Protection against EMI
Network Interface Card (NIC)
A built in component of a motherboard or an expansion card used to connect the system to a network.
- has a unique MAC address
Comes with LED status lights
- link light — shows if a network signal is present
- active light — flickers when packets are bing transferred
- speed light — changes colour depending on transfer speed
Unmanaged Switch
- works without configuration (stores a database of MAC address on the network)
- built into SOHO routers
- 4 or 8 ports
-No virtual Lan/ low cost
Managed Switch
- Used in large corporate networks
- Traffic prioritization
- Redundancy support
- Port Mirroring
- Simple Network Management Protocol (SNMP)
- remote configuration
Power over Ethernet (PoE)
A switch cable of sending power to a device on a network via an ethernet cable Cat 5 or better
- PoE = 15.4W
- PoE+ = 25.5W
- PoE++ = 71.3W
None PoE switches can have an injector that would supply power for PoE
MAC Address
Media Access Control
- the physical address of a device on a network assigned by a NIC
- unique 48-bit identifier code
802.11n (Wi-fi 4)
- 5GHz or 2.4 GHz
- 40Mhz Data channel
- 600Mbps
- 4x MIMO (Multiple-Input Multiple-Output) can transmit/receive from multiple antennas
802.11ac (Wi-Fi 5)
- 5GHz
- 160MHz Data channel
- 7Gbps
- 8x DL MU-MIMO (Download Multiple user MIMO) send data up 4 machines at time
802.11ax (Wi-Fi6)
- 5GHz or 2.4GHz
- 20, 40, 80 & 160Mhz Data channel
- 1.2 - 9.6Gbps
- 8x DL & UL MU-MIMO (DL & Upload MU-MIMO)
-OFDMA – can sustain higher data rates when more machines are connected to the access point
Wireless Frequencies
2.4GHz
- Longer wavelength = long distance & able to moves through solids easily
- Limited amount of channels = more congestion
- Slower data rate
5GHz
- Shorter wavelength = shorter distance & difficulty moving through solids
- more channels = less congested
- Higher data rate
Wireless Channels
Wireless channels: 1, 6, 11 ( don’t cause any interference with eachother)
2.4GHz
- 30-45m
- 14 overlapping channels (interference)
5GHz
- 30m
- 23 non-overlapping channels
Wireless Network Types
Basic Service Set (BSS)
- A network with a singular access point
Extended Service Set (ESS)
- A network with multiple access points
BSSID
- MAC address for the access point of a BSS
Public IP Address
Is the IP address that the ISP assigns to a network via a router that allows the network to access the internet
Private IP Address
An IP address that is used for internal communication on a private network, it does not have internet routing capabilities.
- assigned by router
Private IP range:
10.0.0.0
172.16.0.0
192.168.0.0
NAT
Network Access Translator
A part of a router that translates a devices private IP address into a public IP address, so that the device can access the internet.
TCP/IP
Is a protocol suite that specifies how devices exchange data over a network, it’s designed to move large amount of data.
TCP/IP Layers
- Application Layer
- Transport Layer
- Internet Layer
- Link/Network Link Layer
ISP
Internet Service Provider
- Provides the gateway for a network to access the internet
- ISPs administers IP address, register domain names and host emails & website
TCP
Transmission Control Protocol is a secure protocol that verifies that data is received
- connected orientated
- Secured Communication
- data transmission verification
- Reorder out of order data transmission
- Flow Rate control over of data transmission
DNS
Domain Name Server
A server that fetches IP address for website from a hierarchal database structure where the Root (.) server is the highest followed by extension sever (‘com’, ‘gov’, ‘co’, ect)
- ICANN manage and register domain names
IPv4
Primary IP address protocol used to communicate on an network
Consist of 32 binary digits:
11000000. 10101000. 00000001. 10000011
- each 8 bit is a 1 byte which is 1 Octet
Can be converted into dotted decimal notation dividing each Octet into a value:
198. 41.16.9
Total range: 4.3 Billion addresses
IPv6
Newer form of IPv4 with 128bit, uses hexadecimal notations (0-9, A-F).
- 8 octet
- last 64bit is the host IP address
Range: 340 Undecillion Addresses
- IPv6 LAN is called ‘link-local’
- nodes in the same link are ‘Neighbours’
Satellite Internet Connection
Communicates with devices via satellites
- Expensive
- High latency 250ms
- Line of sight required
Fiber Internet connection
- more expensive than copper
-High bandwidth - long distances
Cable Broadband
Copper wire that transmits different frequencies for different types of data
DOCSIS
-Data Over Cable Service Interface Specification
- high speed
DSL / ADSL
- Digital Subscriber Line
- Asymmetric DSL
- different upload and download speeds
- uses telephone lines
Cellular Internet Connections
Cellar Networks
- data being sent over mobile phones that are connected via tethering/ hotspot
WISP
Wireless Service provider
- transmits signals via local antenna
- uses cellar communications (5G)
WISP types:
-long range Fixed Wireless connection
- Satellite (LoS)
Dynamic IP Addresses
IP address are automatically assigned to devices within a provate network by a DHCP server
Dynamic Host Configuration Protocols(DHCP)
- Server that automatically assigns IP addresses of all systems on a network
Static IP Addresses
IP address for devices on a private network (cannot access internet) that has been manually assigned so that it doesn’t change
- Disable DHCP on the device
- set IP reservation on the IP address that will associate a MAC address with an IP address
APIPA
Automatic Private IP Addressing
(link-local address)
- An address assigned to a devices when it cannot access a DHCP
- Devices will not be able to access the internet but will be able to communicate with other devices on the network
- IP address range:
169.254.0.0 - 169.254.254.255
IPv6 short hand notation
1) Remove leading zeros
2) first multiple sequences (2 or more) of zeros can be replaced with ::
2001:0db8:0000:0000:0abc:0000:def0:1234
= 2001:db8:0000:0000:abc:0:def0:1234
= 201:db8::abc:0:def0:1234
Port
Unique ID for a service using TCP or UPD for transport.
Attenuation
Signal degradation over cables
Ethernet cabling types
U - unshielded
S - Braided
F - Foil shielding
I - Direct burial
Wiring Standards (TIA/EIA 568A)
-White + Green
-Green
-White + Orange
-Blue
-White + Blue
-Orange
-White + Brown
-Brown
Wiring Standards TIA/EIA 568B
-White & Orange
-Orange
-White & Green
-Blue
-White & Blue
-Green
-White & Brown
-Brown
Cable tester
A devices that both ends of a ethernet cable gets connected to that checks that the cable is functioning by sending and recieving signals on the wire
Tap
Intercepts network traffic and can send a copy of the network packet to a capture device.
- active or passive
Port Mirroring
Redirects network packets to be analysed
Fiber optic connectors
- Straight Tip (TP)
- Subscriber Connector (SC)
- Lucent/Local Connector (LC)
Network Hardware device
Is a device that allows a computer to connect to a network via a certain network media (ethernet, fiber) to forward data between computers
Long ranges Fixed Wireless
Wireless technology that can bridge between 2 networks. Two antennas are fixed and pointing at eachother that connects two LAN,l
- laying cable not required
- No need to use ISP
- Radio configuration must be set up correctly
-
IXPs
Internet exchange points
Connects all ISP together on a high bandwidth connection
Broadband Internet Access
Multiple streams of data types through one access point over different frequencies (video, data, voice)
DOCSIS (data on a cable service interface specification)
- 1Gbps
- shared with neighbours (degrades speed)
DSL
Fiber to Premises
ONT (optic network terminal)
- connects fiber network to copper RJ45 network
FTTP
- connects fiber directly to your premise
Router
A devices that allows a network to be connected to the internet via an ISP.
Consists of 2 IP address:
- one that connects to the ISP and the other that connects to your network
- It can also divide a physical network into a logical network
-VLAN communicates through routers
- can filter and monitor traffic flowing through
Hops
Is the logical forward decision that routers make to reach it’s target destination. (Jumps required to reach end point)
- IP packets commonly have 30 Hops
(Time to live) Before it is discarded
Link/Network Interface
The lowest TCP/IP layer
Responsible for connecting and transfers data over a network via the uses of MAC Address (does not connect over internet) and consists of the medium in which the network communicates, (Ethernet, WiFi, Optic)
- sends data across the network in “Frames”
Internet Layer
IP layer
Allows a network to connect and communicate over the internet via an ISP with the uses of an IP Address
- sends data as across the internet as “packets”
Transport Layer
Layer that defines which format the data will be transmitted in.
TCP - secure transmission connection - orientated
UDP - fast transmission connectionless
Application layer
Defines which protocol and port the application will use in order to transmits and receive data
- HTTP, DNS, FTP
Subnet Mask
Is a 32bit encoded address of the Host and Network ID of an IPv4 addres .
- First 3 Octet = Network ID
- Last Octet = host ID
255.255.255.0
255 in binary = 11111111
Default Gateway
The IP address of a router that connects to the internet.
Routers network adapter
- IP address connecting to ISP
- IP address connecting router to your network
Host IP Configuration
Parameters that are required for a devices to correctly connect to the internet
- Subnet mask
- IP address
- Default Gateway
- DNS
DHCP
Dynamic Host configuration Protocol
- assign Host IP configuration on boot
(Subnet, IP address, default Gateway, DNS)
- Can have a reservation list of IP address that the DHCP won’t assign to a device
Private IP address
IP Address used within a LAN that the DHCP will use to assign to devices.
- unable to connect to the internet
10.0.0.0 or 172.0.0.0 or 192.0.0.0
NAT
Network Address Translator (IPv4)
A component of a router/default Gateway that converts your Private IP addresses into a singular Public IP address to surf to web
UDP
User Data Protocol is a fast data transmission protocol
- connectionless
- Fast communication (live )
- No data transmission verification
- No flow rate Control of data transmission
DHCP Sever configuration
Properties that DHCP configures devises with:
- IP address
- Subnet mask
- default Gateway
- DNS
- lease duration
DHCP process
Steps that DHCP takes to configure a device on the network
DORA:
1 Discover - devices tries to locate DHCP
2 Offer - DHCP offers IP to device
3 Request - device request IP from offer list
4 Acknowledge - DHCP confirms new device IP as well as all Host configuration (IP address, Default Gateway, DNS, subnet mask)
DHCP lease duration
Is the configured time that DHCP assigns an IP address to a device.
- checks with DHCP at 50% and 87.5% of lease time to ensure that device still has a connection to DHCP, if no communication then APIPA is assigned.
Static IP Address setup
- Navigate to Network Adapter
- Open WiFi properties
- locate TCP/IPv4
- Select to manual configure IP
- set up new IP Address, Subnet mask, default Gateway & DNS servers
DNS Records
Address Record
- Defines the IP address of a computer name
- A record (IPv4)
-AAAA record (IPv6)
MX (Mail Exchange Record)
- Determines the name for the Mail server
RR (Resources Records)
- database records of devices and roles on DNS
- stores over 30 records
Text Record
- human only readable text used for note taking
DNS Spam Management
SPF - Sender Policy Framework
DKIM - Domain Keys Identified Mail
DMARK - Domain-Based Message Authentication, Reporting and Conformance
DMARK
Domain-Based Message Authentication, Reporting & Conformance is a DNS security measure that prevents unauthorized emails
- an extension of SPF & DKIM
DKIM
Domain Keys Identified Mail is a DNS security measure that digital signs domains outgoings mail That is validated by mail sever
SPF
Sender Policy Framework is a list of servers on a DNS that are authorised to send emails for a given domain and critical information. Mail server checks if mail comes from authorised host.
- prevents mail spoofing
Network Host Service
Authentication server
DHCP/DNS
LPAD
NetBIOS/NetBT
Inventory Management Services
- SNMP (Simple Network Management Protocol)
- Endpoint Management
- Syslog
