Networking Fundamentals​, Quick Notes – Connectivity Options Part 1

Connectivity Options

Computers can be connected in many ways through various technologies.

 

Connectivity Type

Speed

Ease of Setup

Cost

Serial Port

Very Low

Medium

Very Low

Parallel Port

Very Low

Medium

Very Low

Infrared

Very Low

Medium

Very Low

Bluetooth

Low

Easy

Very Low

Crossover or Straight-through Cable

Very High

Easy

Low

Wi-Fi

High

Easy

Low

Powerline

High

Medium

Medium

Hub

Medium

Easy

Very Low

Network Switch

Very High

Depends

Depends

SOHO Router

Medium

Easy

Low

USB

Medium

Medium

Medium

IEEE 1394

Medium

Medium

Medium

Connectivity Types, a rough guideline

Ethernet

Ethernet refers to collection of technologies used in LAN. Ethernet uses co-axial, UTP & Fiber-optic links for connections.

Network Topology

  • Representation of devices in a network (theoretical/conceptual design of a network).
  • Types
    • Bus
    • Ring
    • Star
    • Mesh

Bus Topology

 

 

Star Topology

 

Ring Topology

 

Mesh Topology

Bus Topology

  • Computers connected to a single backbone (Co-Axial Cable).
  • Terminators are used at both ends, to indicate endpoints.
  • Repeaters (and hubs) are used to extend networks.
  • Single break anywhere causes entire network to be down.
  • Types: 10BASE2 (Thinnet) & 10BASE5 (Thicknet)

Star Topology

  • Computers connected to a centralized device, like a hub or network switch.
  • If the hub or network switch goes down, entire network gets affected.

Ring Topology

  • Similar to Star, but involves a closed loop (Physically Star, Logically Ring).
  • Computers are connected through Token Ring Card & MSAU (Multistation Access Units)
  • Data travels in a “Ring” fashion (Referred to as Token Passing Method).

Mesh Topology

  • Connected non-hierarchically & Dynamically to achieve connectivity.
  • Nodes take care of choosing route.

Serial Port

Serial Port Connectivity

  • Found on very old computers.
  • Transfer one bit a time, sequentially.
  • Follows Recommended Standard 232 (a.k.a. RS-232).
  • Used usually for connecting to Dial-Up Modems & Serial Printers.
  • Typical Speeds – 9600, 19200, 38400, 57600 and 115200 bit/s.
  • Replaced by USB & FireWire, Industrial & commercial usage exist.

Serial Port Pin-Out

Parallel Port

Parallel Port Connectivity

  • Found on very old computers.
  • Transfer 8 bits at a time, in parallel.
  • Follows IEEE 1284 Standard.
  • Speed Range: 150 kbit/s – 2.5 MB/s.
  • Popular for connecting Printers, Scanners, Zip Drives, etc.
  • Replaced by USB & FireWire, Industrial & commercial usage exist.

Parallel Port Pin-Out

Infrared

Infrared Connectivity

  • Low Speed Wireless.
  • Follows IrDA (Infrared Data Association) standards.
  • Works only in a direct line of sight & 10 feet approx.

Technology

Speed

IrDA-Control

72 kbit/s

9 kB/s

IrDA-SIR

115.2 kbit/s

14 kB/s

IrDA-FIR

4 Mbit/s

500 kB/s

IrDA-VFIR

16 Mbit/s

2 MB/s

IrDA-UFIR

96 Mbit/s

12 MB/s

IrDA-Giga-IR

1024 Mbit/s

128 MB/s

Bluetooth

Bluetooth Connectivity

  • Low to medium speed Wireless Technology.
  • Simple “Pairing” mechanism to connect to each other.
  • Standards managed by the Bluetooth Special Interest Group (SIG).
  • Designed for shorter distances & low-bandwidth applications.
  • Widely implemented in Mobile Phones, Laptops, etc.
  • Suitable for transferring small to medium sized files.

Class

Range

1

100 Meters / 300 Feet

2

10 Meters / 33 Feet

3

1 Meter / 3.3 Feet

Technology

Speed

Bluetooth 1.1

1 Mbit/s

125 kB/s

Bluetooth 2.0+EDR

3 Mbit/s

375 kB/s

Bluetooth 3.0

25 Mbit/s

3.125 MB/s

Bluetooth 4.0

25 Mbit/s

3.125 MB/s

Bluetooth 5.0

50 Mbit/s

6.25 MB/s

Twisted Pair Cable

Connectivity using a patch cable, through Ethernet ports

  • Used in telephone & computer networks.
  • “Twisted” at predefined intervals to cancel out EMI (Electro Magnetic Interference).
  • Types
    • UTP: Normal 2 or 4 pair wires.
    • STP: UTP with a special extra shield (has additional foil layer to protect against EMI).
 

Unshielded Twisted Pair

Shielded Twisted Pair

 

RJ-45 Connector

Crimping Tool

Cable Tester

  • Registered Jack, RJ-45 is the de facto standard connector for Ethernet networks.
  • RJ-11 is the de facto standard for telephone networks.
  • Crimping Tool used for terminating cables into jacks (process referred to as “Crimping”).
  • Cable Testers used for checking connectivity at both ends.

Cables are categorized according to standards:

Category

Bandwidth

Speed

Application

CAT 1

1 MHz

10

Used in telephone networks

CAT 2

4 MHz

4 Mbps

Used in Token Ring Networks

CAT 3

16 MHz

10 Mbps

Used in Ethernet Networks

CAT 4

20 MHz

16 Mbps

Used in Token Ring Networks

CAT 5

100 MHz

100 Mbps

Used in Ethernet Networks

CAT 5e

100 MHz

1000 Mbps

CAT 6

Up to 250 MHz

1000 Mbps

Standards

Name

Standard

Speed (Mbps)

Pairs

Max distance (m)

Cable

10BASE-T

802.3i

10

2

100

Cat 3

100BASE-TX

802.3u

100

2

100

Cat 5

1000BASE-T

802.3ab

1000

4

100

Cat 5e

1000BASE-TX

TIA/EIA-854

1000

4

100

Cat 6

2.5GBASE-T

802.3bz

2500

4

100

Cat 5e

5GBASE-T

802.3bz

5000

4

100

Cat 6

10GBASE-T

802.3an

10000

4

100

Cat 6A

25GBASE-T

802.3bq

25000

4

30

Cat 8

40GBASE-T

802.3bq

40000

4

30

Cat 8

For example, 1000BASE-T:

  • 1000 indicates speed in Mbps.
  • “BASE” indicates baseband.
  • “T” – Twisted Pair.

Note:

  • 10 Mbps is referred to as Ethernet.
  • 100 Mbps is referred to as Fast Ethernet.
  • 1000 Mbps is referred to as Gigabit Ethernet.

 

Hubs & Network Switches have MDI/MDIX, a type of interface for connecting twisted pair cables. Cables are wired either following straight-through (Medium Dependent Interface) or, cross-over (Medium Dependent Interface Cross-over) configuration (irrespective of cable standard T568A or T568B).  

Pin #

T568A

T568B

1

White / Green Stripes

White / Orange Stripes

2

Solid Green

Solid Orange

3

White / Orange Stripes

White / Green Stripes

4

Solid Blue

Solid Blue

5

White / Blue Stripes

White / Blue Stripes

6

Solid Orange

Solid Green

7

White / Brown Stripes

White / Brown Stripes

8

Solid Brown

Solid Brown

Cable Standard: Color coded for easy understanding.

In Straight-through cables, pin assignments match at both ends (i.e. Pin 1 connects to Pin 1, Pin 2 connects to Pin 2, etc.). Straight-Through cables are most common and used widely. In other words, transmitting & receiving pairs match at both ends. Straight-through cables are used for connecting dissimilar devices; for example, connecting a hub/network switch (MDI-X Interface) to a computer (MDI Interface).  

In Cross-over cables, pin assignments are swapped (transmitting & receiving pairs are swapped). Cross-over cables are used when connecting similar devices; for example, connecting one computer (MDI Interface) to another computer (MDI Interface).

2 Pair Straight Through (1-1, 2-2, 3-3, 6-6)

2 Pair Cross Over (1-3, 2-6, 3-1, 6-2)

4 Pair Cross Over Cable  (1-3, 2-6, 3-1, 6-2, 5-8, 7-4, 4-7, 8-5)

Network Interface Card (NIC)

Direct Connectivity using NIC

  • Device that enables computers to connect to a network.
  • Layer 1 & 2 (Physical & Data Link).
  • Has hard-coded Unique MAC Address.

Media Access Control (MAC) Address

  • Also known as “Physical Address”.
  • Each NIC has one MAC address, usually not changeable.
  • Used for addressing purposes (identifying a node) on a physical network.
  • Uses 48-bit (248) addressing scheme as governed by IEEE.
  • 281,474,976,710,656 Possible Physical Addresses.
  • 24-bit part reserved for Organization (OUI) & 24-bit part for the hardware (NIC).
  • Denoted in hexadecimal format, separated by hyphens (Example: AA-BB-CC-DD-EE-FF).

MAC Address Structure

 Typical features of NIC:

  • BOOT ROM is a special chip (mostly integrated with NIC) that allows to “boot” a computer through network (load an operating system from a remote computer).
  • Power Management to conserve & manage power used by the NIC, usually controlled through the operating system.
  • Auto-negotiation feature to automatically decide NIC settings such as speed, duplex mode, etc.
  • Wake-On-LAN (WOL) feature allows a computer to be turned on from a remote computer.
  • Link aggregation feature combines multiple NIC’s to provide higher throughput; for example, combine two 100 Mbps NIC’s to achieve 200 Mbps throughput.
  • Modern NIC’s support “Auto MDI/MDI-X”, a feature that detect and choose required cable configuration automatically; so either a straight-through or a cross-over cable can be used.

Single Port NIC

Dual Port NIC

Quad Port NIC

USB to Ethernet Adapter

PCMCIA Ethernet Adapter

USB Type C to Ethernet Adapter

 

Motherboard with 4 NIC

Ethernet Port on Laptop

 
  • NIC’s are integrated on most desktop computers & laptops. NIC settings are controlled through BIOS settings and/or Operating systems.
  • For desktop computers: PCI, PCIe or USB types may be used.
  • For laptops: USB, Type C Ethernet Converter, CardBus or ExpressCard types may be used.

Note: PCI interface is almost obsolete, replaced by PCIe on recent computers; it is recommended to check the technical specification of a computer before purchasing any type of NIC.

Wired Adapters Worksheet

Vendor

 

 

 

Model

 

 

 

Interface

PCI

 

 

 

PCIe

 

 

 

USB

 

 

 

PCMCIA

 

 

 

CardBus

 

 

 

32 / 64 bit

 

 

 

# of RJ-45 Ports

 

 

 

# of Fiber Optic Ports

 

 

 

Features

WOL Support (Yes / No)

 

 

 

Boot ROM (Yes / No)

 

 

 

Power Management (Yes / No)

 

 

 

Fail Over Support (Yes / No)

 

 

 

Supported OS (Device Drivers)

Microsoft Windows

 

 

 

Linux

 

 

 

MAC OS

 

 

 

Standard Compliance

IEEE 802.3

 

 

 

IEEE 802.3u

 

 

 

IEEE 802.3ab

 

 

 

IEEE 802.3x

 

 

 

IEEE 802.3z

 

 

 

IEEE 802.1q

 

 

 

IEEE 802.1p

 

 

 
  • View list of installed Network Adapters
    • START > RUN > DEVMGMT.MSC
    • Expand Network Adapters

View all Network Adapters using Device manager

Example based on above image:

  • Realtek PCIe GBE Family Controller – 1000 Mbps Wired NIC.
  • Qualcomm Atheros QCA61x4 Wireless Network Adapter – Wireless NIC.

Note: You may find “Bluetooth Network Adapters”, “Virtual adapters”, etc. installed for specific purposes by the operating system or by a 3rd party software; such adapters may be researched further to understand their purpose. Do NOT compare “Virtual” with “Physical” adapters.

  • View all Network Adapters (including Virtual, Hidden, etc.)
    • Select View > Show hidden devices

Output listing all network adapters

For example:

  • Microsoft 6to4 Adapter: Encapsulate IPV6 packets into IPv4 packet.
  • Microsoft ISATAP Adapter:  Inter Site Automatic Tunneling Address Protocol, used for IPV6.
  • WAN Miniport (PPPOE): Used for establishing connectivity using PPPOE over Ethernet.

Note: Above topics may be explored once there is sufficient understanding of basic networking, hence not covered in-depth.

 

Network Connections (Microsoft Windows)

Network connections with names such as “Local Area Connection”, “Local Area Connection 2”, “Bluetooth Network Connection” are automatically created by Microsoft Windows for human reference during installations. Microsoft Windows binds basic protocols & services to each connection, whenever a new network adapter is installed.

Connection names are for reference purposes, can be renamed to anything as it has NO technical impact (for example, “Local Area Connection 2 can be renamed as “Ethernet” or “Wi-Fi” for easy identification).

  • View list of network connections
    • START > RUN > NCPA.CPL

Network Connections

NETSH is a command line utility to manage network configuration.

  • View list of Wired Adapters:
    • START > RUN > SERVICES.MSC
    • Select Wired AutoConfig, Right-click and Select “Start”

Note: Wired Autoconfig Service needs to be started for the following command to work.

  • CMD > netsh lan show interfaces

Output listing only Wired NIC (Disconnected) along with Connection Name, Model & MAC

  • CMD > netsh lan show interfaces

Output listing only Wired NIC (Connected)

WMIC ( Windows Management Instrumentation Command-line) is a command line interface to WMI; WMI is used to manage several aspects of Microsoft Windows Operating systems through it’s interface and scripting languages.  

  • View list of NIC using WMIC:
    • CMD > wmic nic get name, macaddress, speed

Output listing all adapters (including inactive connections, Virtual & hidden adapters)

  • View Active (Connected) NIC:
    • CMD > wmic nic where “NetEnabled=’true'” get Name, MACAddress, speed

Output listing active adapters: Name, MAC & Speed

Powershell is a configuration management framework, which can be used for multiple purposes.

  • View details for a specific adapter using Powershell:
    • CMD > Powershell
    • Powershell >Get-NetAdapter -Name “CONNECTIONNAME” | where Status -eq “Up” | select InterfaceDescription, LinkSpeed, fullduplex | ft -autosize

Output listing Name, current speed & select duplex mode for a specific wired connection

  • View All adapters using Powershell:
    • CMD >Powershell > Get-NetAdapter -Name “*”

Output listing all adapters (Disconnected & Disabled if any), Link Status, MAC Address & Speed

Note: ifIndex refers to Interface Index, an internal reference ID maintained by the Operating System.

  • CMD >Powershell > Get-NetAdapter -Name “*” | Format-List

Output listing all adapters, list view

  • View Physical Adapters:
    • CMD > Powershell > Get-NetAdapter -Name “*” –Physical| Format-List

Output listing NIC, Supported IEEE Standards, Link Status, MAC Address & Speed if connected 

Note: “| Format-List” option may be used for a list style view and is optional.

  • View all Adapters (including hidden):
    • CMD > Powershell >Get-NetAdapter -Name “*” -IncludeHidden | Format-List

Output listing all NIC, Link Status, MAC Address & Speed

  • View details of a particular NIC using Powershell:
    • CMD >
      • Powershell > Get-NetAdapter -Name “CONNECTIONNAME” | Format-List-Property “*”

Output listing details of an NIC

IPCONFIG (Internet Protocol Configuration) is a command line utility to manage IP configuration, that can also be used for viewing list of network cards.

  • View list of network adapters on a computer:
    • CMD > ipconfig /all

Output listing Host Name (Computer Name)

Wired Adapter: a) Manufacturer, Model & Adapter type & b) MAC Address in hexadecimal format

Wireless Adapter: a) Manufacturer, Model & Adapter type & b) MAC Address

Tip: Use ”ipconfig /all | more” to view line by line.

GETMAC is a command line utility to view MAC addresses.

  • View Connection Name & MAC Address:
    • CMD > getmac /v /FO:LIST

Output listing Connection Name, Network Adapter & MAC Address

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