Networking Fundamentals​, Quick Notes – Connectivity Options Part 3

Wi-Fi

Connectivity using Wi-Fi

  • Wi-Fi, a trademark of Wi-Fi Alliance.
  • Refers to collection of Wireless Technologies related to IEEE 802 standards.
  • Works similar to a radio for connectivity, using specific radio frequencies.
  • Works best in open environments, barriers limit distance & speed.
  • Recommended where wired connections are not feasible.
  • Also referred to as “P2P Network” or, “Wi-Fi Direct”.
  • Follows CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) access method.
  • Network coverage is typically 100 meters.
  • Security is usually supported through WEP & WPA.
  • Modes
    • ADHOC Mode: Computers are connected to each other directly,without a base station.

ADHOC Mode, Theory maximum 256 nodes.

  • Infrastructure Mode: Wireless clients connect to each other through a base station; also connect wireless networks to wired networks through the base station.

Infrastructure Mode, Theory maximum 2048 nodes.

Note: Maximum number of connections entirely depends on hardware & technology.

Standards

Generation

IEEE Standard

Speed Range

Radio Frequency

Wi-Fi 1

802.11b

1 to 11 Mbit/s

2.4 GHz

Wi-Fi 2

802.11a

1.5 to 54 Mbit/s

5 GHz

Wi-Fi 3

802.11g

3–54 Mbit/s

2.4 GHz

Wi-Fi 4

802.11n

72–600 Mbit/s

2.4/5 GHz

Wi-Fi 5

802.11ac

433–6933 Mbit/s

5 GHz

Wi-Fi 6

802.11ax

600–9608 Mbit/s

2.4/5 GHz/1–6 GHz ISM

Note: IEEE 802.11n devices may use 2.4 and/or 5 GHz frequency range depending on the model; it is recommended to check technical specification of the product for frequency details.

SSID

  • SSID (Service Set Identifier) refers to the network name for a wireless network.
  • SSID’s are advertised (broadcast) for clients to discover available wireless networks.
  • Maximum 32 Characters, Case Sensitive & Special Charterers are allowed.
  • Wireless Client can be associated with only ONE SSID at any time (limited to one connection)
    • BSSID: Basic SSID is the MAC address of an AP.
    • ESSID: Extended SSID refers to BSSID used across multiple APs using the same BSSID.

Note: In ADHOC mode, SSID is termed as “Independent basic service set (IBSS)”

Wireless Channels

  • Connectivity is established through regulated channels / frequencies.
  • 4 GHz range is widely used by many devices like Radio Remote Controls, Microwave Oven, Cordless Phones, Baby Monitors, etc. acting as barriers to Wi-Fi Signals(causes interference).
  • Limited number of consumer devices use 5 GHz band as compared to 2.4 GHz.
  • Overlapping & Non-Overlapping in certain standards.

Standard

Frequency

Bandwidth

Speeds (Mbps)

Max. Stream(s)

IEEE 802.11b

2.4 GHz

20 MHz

1, 2, 5.5 & 11

1

IEEE 802.11a

5 GHz

20 MHz

6, 9, 12, 18, 24, 36, 48 & 54

1

IEEE 802.11g

2.4 GHz

20 MHz

6, 9, 12, 18, 24, 36, 48 & 54

1

IEEE 802.11n

2.4 / 5 GHz

20 MHz

7.2, 14.4, 21.7, 28.9, 43.3, 57.8, 65 & 72.2

4

40 MHz

15, 30, 45, 60, 90, 120, 135 & 150

4

IEEE 802.11ac

5 GHz

20 MHz

Up to 87.6

8

40 MHz

Up to 200

8

60 MHz

Up to 433.3

8

80 MHz

Up to 866.7

8

Reference(s):

Wireless Security

In wireless networks signals are transmitted over air,  prone to eavesdropping. Wireless networks are secured by implementing wireless security standards such as WEP or, the more recent WPA.

Note: “Open Network” refers to wireless networks that have NO security measures, anyone can join the network without any password.

  • WEP
    • Wired Equivalent Privacy, 1stencryption algorithm for Wireless networks.
    • Option to use 64-bit, 128-bit or 256-bit Encryption.
    • Outdated (yet still used in some scenarios).
  • WPA
    • Wi-Fi Protected Access.
    • Uses Temporal Key Integrity Protocol.
    • Unique 128-bit key for each packet (more secure).
  • WPA2
    • Much stronger than WEP or WPA.
    • Uses CCMP (Counter Mode Cipher Block Chaining Message Authentication Code Protocol).

Note: It is highly recommended to use WPA2 if available, as it is most secure compared to any other wireless security solution for now.

WPS – “Wi-Fi Protected Setup” a feature usually found on SOHO Routers and Access points, enable simplified wireless security through use of a simple PIN number or Push Buttons instead of prompting for passwords when users attempt to connect to wireless networks. It is recommended to use WPA or WPA2 instead of WPS, as WPS is not as secure as WPA/WPA2.

MIMO

MIMO enables simultaneous use of multiple radio links to achieve higher speeds, a feature introduced in IEEE 802.11n. Devices or computers that support MIMO usually have 2 or more antennas, to take advantage of this feature.

  • SU-MIMO
    • Single-User, Multiple Input, Multiple Output.
    • One client at a time.
  • MU-MIMO
    • Multi-User, Multiple Input, Multiple Output.
    • Multiple clients at the same time.

SU-MIMO, 4 Streams to a single client

MU-MIMO, 2 streams each to 2 clients

Note: Client devices must support MU-MIMO to take advantage; MU-MIMO USB dongles / cards are being introduced and handful devices support MU-MIMO out-of-the-box.

IEEE 802.11ac (popular as of now)

  • Products advertised by manufacturers based on combined throughput. Example: AC1900 = 600 (2.4 GHz) + 1300 (5 GHz).

Type

2.4 GHz

5 GHz

Mbit/s

[all 40 MHz]

Mbit/s

[all 80 MHz]

AC450

433

1 stream @ MCS 9

AC600

150

1 stream @ MCS 7

433

1 stream @ MCS 9

AC750

300

2 streams @ MCS 7

433

1 stream @ MCS 9

AC1000

300

2 streams @ MCS 7

650

2 streams @ MCS 7

AC1200

300

2 streams @ MCS 7

867

2 streams @ MCS 9

AC1300

400

2 streams @ 256-QAM

867

2 streams @ MCS 9

AC1300

1,300

3 streams @ MCS 9

AC1350

450

3 streams @ MCS 7

867

2 streams @ MCS 9

AC1450

450

3 streams @ MCS 7

975

3 streams @ MCS 7

AC1600

300

2 streams @ MCS 7

1,300

3 streams @ MCS 9

AC1700

800

4 streams @ 256-QAM

867

2 streams @ MCS 9

AC1750

450

3 streams @ MCS 7

1,300

3 streams @ MCS 9

AC1900

600

3 streams @ 256-QAM

1,300

3 streams @ MCS 9

AC2100

800

4 streams @ 256-QAM

1,300

3 streams @ MCS 9

AC2200

450

3 streams @ MCS 7

1,733

4 streams @ MCS 9

AC2300

600

4 streams @ MCS 7

1,625

3 streams @ 1024-QAM

AC2400

600

4 streams @ MCS 7

1,733

4 streams @ MCS 9

AC2600

800

4 streams @ 256-QAM

1,733

4 streams @ MCS 9

AC3000

450

3 streams @ MCS 7

1,300 + 1,300

3 streams @ MCS 9 x 2

AC3150

1000

4 streams @ 1024-QAM

2,167

4 streams @ 1024-QAM

AC3200

600

3 streams @ 256-QAM

1,300 + 1,300

3 streams @ MCS 9 x 2

AC5000

600

4 streams @ MCS 7

2,167 + 2,167

4 streams @ 1024-QAM x 2

AC5300

1000

4 streams @ 1024-QAM

2,167 + 2,167

4 streams @ 1024-QAM x 2

Wireless NIC

Computers connected via Wireless NIC

  • Layer 1 & 2 (Physical & Data Link).
  • Follows IEEE 802.11 standards.
  • Available as PCI, PCIe, USB, Integrated, etc.
  • Most recent laptops, all-in-one personal computers, mobile phones include WNIC.

WNIC for Desktops

WNIC module for Laptops

USB WNIC

 

USB WNIC Mini Dongle

WNIC, 4 Antennas

 

Note: It is recommended to check the technical specifications of WNIC for exact details on standards supported by an NIC and other capabilities such as MIMO.

Wireless Adapters Worksheet

Vendor

     

Model

     

Interface

PCI

     

PCIe

     

USB

     

PCMCIA

     

CardBus

     

32 / 64 bit

     

Supported OS (Device Drivers)

Microsoft Windows

     

Linux

     

MAC OS

     

Standard Compliance

IEEE 802.11b

     

IEEE 802.11g

     

IEEE 802.11a

     

IEEE 802.11n

     

IEEE 802.11ac

     

Frequency

2.4 GHz

     

5 GHz

     

Dual Band

     

Triband

     

Wireless Security Support

WEP, 64-bit

     

WEP, 128-bit

     

WPA

     

WPA2

     

WPS

     

Antennas

1×1 SISO

     

2×2 MIMO

     

3×3 MIMO

     

4×4 MIMO

     

Detachable (Yes/No)

     
  • View list of WNIC:
    • CMD > netsh wlan show interfaces

Output listing only Wireless Adapters (Not associated)

  • View IEEE standards supported by WNIC:
    • CMD > netsh wlan show drivers


Output a) IEEE 802.11 standards supported by the Wireless adapter

  • Show Wireless Adapter’s capabilities (Microsoft Windows 10)
    • CMD > netsh wlan show wirelesscapabilities

Output listing features supported by WNIC

Access Point

Wireless AP with 2 clients, 3rd Client connected via Wireless Extender

  • Simple device (a.k.a Base Station) to centralize wireless networks.
  • Wireless Access Point is typically used to “connect” wireless networks to wired networks.
  • Wireless Range Extenders used to extend Wireless Networks (Roaming facility).
  • Wireless Access Points may have facilities for Timed usage, User Management, Guest Access, DHCP Service, Firewall, etc. depending on the model.
  • Indoor AP’s are designed for usage inside homes or small offices, limited coverage.
  • Outdoor AP’s are designed for long distance coverage, between buildings.

Access Point

Outdoor Access Point

Wireless Range Extender

  • View list ofWireless Networks:
    • CMD > netsh wlan show networks mode=bssid

Output (edited to show limited results) listing a) all available Wireless networks, b) Signal strength, c) IEEE standards & d) supported speeds. This particular model supports both 2.4 GHz & 5 GHz.

  • Viewtechnical details of an access point or wireless router:
    • CMD > netsh wcn query SSID=”SSID”

Output listing details of an Access Point/SOHO Router (from a WCN capable device)

  • View Wi-Fi details (Associated):
    • CMD > netsh wlan show interfaces

Output listing Wi-Fi details based on a connection

 Note: “Associated” is the term used in Wireless Networks, instead of “Connected”.

  • View details for a specific connection:
    • CMD > Powershell > Get-NetAdapter -Name “CONNECTIONNAME” | where Status -eq “Up” | select InterfaceDescription, LinkSpeed, fullduplex| Format-List

Output listing Speed & Duplex details for a specific wireless connection

Microsoft Windows maintains details of wireless connections (if connected earlier) as “profiles”.

  • View list of saved Wireless Profiles:
    • CMD > netsh wlan show profiles

Output listing all stored profiles

  • Show details for a specific profile:
    • CMD > netsh wlan show profile PROFILENAME

Output listing preferences of a particular network, as stored on a computer

  • Show Wi-Fi Password (Stored):
    • CMD > netsh wlan show profile PROFILENAME key=clear

Output showing stored wireless password for a specific profile saved earlier (key content)

  • To delete a profile:
    • CMD > netsh wlan delete profile PROFILENAME

Input to delete a profile

  • View Wireless Report (Microsoft Windows 10):
    • CMD > netsh wlan show wlanreport
    • View C:\ProgramData\Microsoft\Windows\WLANReport\WLAN-report-latest.html

Input to generate report (Microsoft Windows 10)

WLAN Report Sample

Wireless Access Point Worksheet

Vendor

     

Model

     

Firewall (Available / Not Available)

     

Parental Control

     

Beamforming

     

Can be used as Wireless Extender? (Yes / No)

     

Frequency

2.4 GHz

     

5 GHz

     

Dual Band

     

Tri Band

     

Wireless Security Support

WEP, 64-bit

     

WEP, 128-bit

     

WPA

     

WPA2

     

WPS

     

Antennas

1×1 SISO

     

2×2 MIMO

     

3×3 MIMO

     

4×4 MIMO

     

Detachable (Yes/No)

     

Standard Compliance

IEEE 802.3

     

IEEE 802.3u

     

IEEE 802.3ab

     

IEEE 802.3x

     

IEEE 802.3z

     

IEEE 802.1q

     

IEEE 802.1p

     

IEEE 802.11b

     

IEEE 802.11g

     

IEEE 802.11a

     

IEEE 802.11n

     

IEEE 802.11ac

     

Powerline

  • Usesexisting power supply lines for network connectivity.
  • Follows HomePlug AV and IEEE 1901 standards.
  • Speeds Up to 500 Mbps.
  • Commercially available as a “kit”, with minimum of 2 adapters.
  • Maximum of 64 adapters (as of now) can be used, depending on the model.
  • Usually does not work across closed circuit breakers.

Two computers connected via Powerline Adapters through Ethernet & One Computer via Wireless

Powerline Adapter

Powerline Adapter, 3 LAN Ports

Powerline Adapter, Wi-Fi

For example:

  1. Insert Straight-Through cable into LAN ports (of computer & Powerline adapter).
  2. Connect Powerline adapter to power socket.
  3. Configure network using the software provided along with Powerline adapter.

Powerline Adapters Worksheet

Vendor

     

Model

     

Ports

# of RJ-45 Ports

     

# of Fiber Optic Ports

     

Standard Compliance

HomePlug AV

     

HomePlug AV2

     

IEEE 1901

     

IEEE 802.3

     

IEEE 802.3u

     

IEEE 802.3ab

     

IEEE 802.3x

     

IEEE 802.3z

     

IEEE 802.1q

     

IEEE 802.1p

     

IEEE 802.11b

     

IEEE 802.11a

     

IEEE 802.11g

     

IEEE 802.11n

     

IEEE 802.11ac

     

USB Ports

Connectivity using “Easy Transfer Cable” via USB

  • Using USB ports for connecting computers require a special type of USB cable like the “Easy Transfer Cable”.
  • Usually require additional software for setting up.
   

USB Bridge Cable

   

IEEE 1394

  • Interface standard for high-speed serial connections.
  • Referred as “FireWire” by Apple Inc.
 

IEEE 1394 Cable

PCIe FireWire Card

 

Note: There are different types of connectors, not listed here.

Standards

Standard

Mbit/s

MB/s

FireWire (IEEE 1394) 100

98.304

12.288

FireWire (IEEE 1394) 200

196.608

24.576

FireWire (IEEE 1394) 400

393.216

49.152

FireWire (IEEE 1394b) 800

786.432

98.304

FireWire (IEEE 1394b) 1600

1.573

196.6

FireWire (IEEE 1394b) 3200

3.1457

393.216

Router

3 Network Switches connected to 2 Routers

  • Operates at Layer 3 (Network).
  • Routes IP packets, across logical networks.
  • Discovers and builds IP tables for routing packets.
  • Can be used for internal enterprise networks and/or external networks like the Internet.
  • Routers are usually complex and require technical expertise as specified by a manufacturer.  
  • May have capabilities such as MAC/IP filtering, firewall, etc.

Note: Do NOT confuse with SOHO/Home/Residential Routers, with an actual enterprise router.

Layer 3: Routers “exchange” routing tables, determine path and route packets

 

 

Enterprise Router

 

 

Quiz 04

1. IEEE standards for WLAN (Wi-Fi):

A. 802.11 b/g B. 802.11 a C. 802.11 n D. 802.11 ac

2. Radio Frequency – IEEE 802.11 a:

A. 2.4 GHz B. 2.8 GHz C. 5 GHz D. None

3. Radio Frequency – IEEE 802.11 b/g:

A. 2.4 GHz B. 2.8 GHz C. 5 GHz D. Both A & C

4. Radio Frequency – IEEE 802.11 ac:

A. 2.4 GHz B. 2.8 GHz C. 5 GHz D. All of the above

5. Radio Frequency – IEEE 802.11 n:

A. 2.4 GHz B. 2.8 GHz C. 5 GHz D. Both A & C

6. Maximum speed supported by IEEE 802.11b:

A. 11 Mbps B. 54 Mbps C. 600 Mbps D. 1 Gbps

7. Maximum speed supported by IEEE 802.11a:

A. 11 Mbps B. 54 Mbps C. 600 Mbps D. 1 Gbps

8. Maximum speed supported by IEEE 802.11g:

A. 11 Mbps B. 54 Mbps C. 600 Mbps D. 1 Gbps

9. Maximum speed supported by IEEE 802.11n:

A. 11 Mbps B. 54 Mbps C. 600 Mbps D. 1 Gbps

10. Maximum speed supported by IEEE 802.11ac:

A. 11 Mbps B. 54 Mbps C. 600 Mbps D. 6.77 Gbps

11. WLAN utilizes _____ technologies for transmissions:

A. OFDM B. IR C. Bluetooth D. None

12. Tethering is also referred to as:

A. Mobile Hotspot B. Wireless Fidelity C. NFC D. None

13. Device required for setting up a Wi-Fi Network:

A. Repeater B. Access Point C. Hub D. Router

14. Peer-to-Peer wireless networks are referred to as:

A. Infrastructure Networks B. ADHOC Networks
C. Peer Level Networks D. All of the above

15. Infrastructure wireless networks require:

A. Repeater B. Access Point C. Hub D. Router

16. Device that acts as a bridge between wired and wireless networks:

A. Repeater B. Access Point C. Hub D. Router

17. Acronym – SSID:

A. Secure Set Identifier B. Simple Set Identifier
C. Synchronous Set Identifier D. Service Set Identifier

18. SSID – Maximum number of characters:

A. 8 B. 16 C. 32 D. 64

19. In wireless networks a device may be associated with _____ SSIDs:

A. 4 B. 1 C. 12 D. Unlimited

20. Dual band devices typically

A. Allow use of both 2.4 GHz and 5 GHz B. Supports longer range
C. Supports more than 1 SSID D. None of the above

21. Acronym – WAP:

A. Wired Access Point B. Wireless Access Point
C. Wireless Area Point D. Wired Area Point

22. _____ refers to unauthorized access of wireless networks.

A. Postpaid B. Secure Connect C. Piggybacking D. None

23. Ways to protect wireless networks:

A. Disable SSID Broadcast B. Implement WPA C. Change default SSID D. All of the above

24. Acronym – WEP

A. Wireless Equivalent Privacy B. Wired Equivalent Privacy
C. Wi-Fi Equivalent Privacy D. Wireless Encrypted Privacy

25. Acronym – WPA

A. Wireless Protected Access B. Wired Protected Access
C. Wi-Fi Protected Access D. Wi-Fi Protected Array

26. Acronym – TKIP

A. Temporal Key Integrity Practice B. Temporary Key Integrity Protocol
C. Temporal Key Intelligent Protocol D. Temporal Key Integrity Protocol

27. Items that cause interference to wireless signals:

A. Steel B. Concrete C. Wood D. All of the above

28. 64 bit WEP uses _____ hexadecimal characters.

A. 8 B. 12 C. 26 D. 10

29. 128 bit WEP uses _____ hexadecimal characters.

A. 8 B. 12 C. 26 D. 10

30. Most recent wireless encryption standard:

A. 128 bit WEP B. 64 bit WEP C. WPA D. WPA2

31. _____ utilizes per-packet key.

A. PoE B. WEP C. WPA D. NoN

32. Acronym – WPS

A. Wireless Protected Setup B. Wi-Fi Protected Setup
C. Wired Protected Setup D. Wired Protected Sync

33. Devices that cause interference to wireless signals:

A. Cordless Phones B. Microwave Ovens C. Baby Monitors D. All of the above

34. Acronym – AES

A. Analytical Encryption Standard B. Alternate Encryption Standard
C. Adverse Encryption Standard D. Advanced Encryption Standard

35. Acronym – MIMO.

A. Multiple-Input; Multiple-Out B. Minute-Input; Minute-Out
C. Micro-Input; Micro-Out D. Macro-Input; Macro-Out

36. MIMO technique is used in:

A. IEEE 802.11g B. IEEE 802.11b C. IEEE 802.11n D. Both A & B

37. Technique that allows connections only if a WAP finds matching address:

A. WEP B. WPA C. MAC Authentication D. IP Spoofing

38. The term ‘IBSS’ refers to:

A. Switched Networks B. Infrastructure Networks
C. ADHOC Networks D. Managed Networks

39. The term ‘BSS’ refers to:

A. Switched Networks B. Infrastructure Networks
C. ADHOC Networks D. Managed Networks

40. Acronym – ESS.

A. Emulated Service Set B. Extended Service Setup
C. Extended Service Set D. Emulated Service Setup

41. Acronym – IBSS.

A. Internet BSS B. Intranet BSS C. Inline BSS D. Independent BSS

42. Network access method used in wireless networks:

A. CSMA/CD B. CSMA/CA C. CSMA/Wi-Fi D. CSMA/CF

43. Acronym – CSMA/CA

A. Carrier Sense Multiple Access/Collision Avoidance
B. Career Sense Multiple Access/Collision Avoidance
C. Carrier Sense Multiple Access/Collision Access
D. Career Sense Multiple Access/Collision Access

44. Acronym – QAM

A. Quad Processor Modulation B. Quadrature Amplitude Modulation
C. Quad Amplifier D. None of the above

45. Technology that allows to form a network using electricity Lines:

A. Powerline B. DSL C. Cable D. ISDN

46. Standards related to Powerline

A. IEEE 1801 B. HomePlug AV C. IEEE 1901 D. IEEE 802.11

47. Standard related to FireWire

A. IEEE 1901 B. IEEE 802.11 C. IEEE 1284 D. IEEE 1394

48. Speeds supported by FireWire

A. 400 Mbps B. 800 Mbps C. 1600 Mbps D. 400 Gbps

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