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):

• https://en.wikipedia.org/wiki/List_of_WLAN_channels
• https://en.wikipedia.org/wiki/IEEE_802.11
• https://en.wikipedia.org/wiki/Quadrature_amplitude_modulation
• https://en.wikipedia.org/wiki/IEEE_802.11ac
• https://en.wikipedia.org/wiki/Wi-Fi_6

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, 1^stencryption 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, 3^rd 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