Transmission Media

Wireless Networking

Wireless Standards

Wireless networking (802.11)

• Managed by the IEEE LAN/MAN Standards Committee (IEEE 802)
• Institute of Electrical and Electronics Engineers

Many updates over time

• Check with IEEE for the latest

The Wi-Fi trademark

• Wi-Fi Alliance handles interoperability testing

Modern standards have a more marketable name

• For example, 802.11ax is Wi-Fi 6

4G and LTE

Long Term Evolution (LTE)

• A “4G” technology
• converged standard (GSM and CDMA providers)
• Based on GSM and EDGE (Enhanced Data Rated for GSM Evolution)
• Standard supports download rates of 150 Mbit/s

LTE Advanced (LTE-A)

• Standard supports download rates of 300 Mbit/s

5G

Fifth generation cellular networking

• Launched worldwide in 2020

Significant performance improvements

• At higher frequencies
• Eventually 10 gigabits per second
• Slower speeds from 100-900 Mbit/s

Significant IoT impact

• Bandwidth becomes less of a constraint
• Larger data transfers
• Faster monitoring and notification
• Additional cloud processing

Satellite Networking

Communication to a satellite

• Non-terrestrial communication

High cost relative to terrestrial networking

• 100 Mbit/s down, 5 Mbit/s up are common
• Remote sites, difficult-to-network sites

Relatively high latency

• 250 ms up, 250 ms down
• Starlink advertises 40 ms and is working on 20 ms

High frequencies — 2 GHz

• Line of sight, rain fade

Ethernet Standards

Ethernet

The most popular networking technology in the world

• Standard, common, nearly universal

Many types of Ethernet

• Speeds, cabling, connectors, equipment

Modern Ethernet uses twisted pair copper or fiber

• The standard defines the media

IEEE Ethernet Standards

The IEEE 802.3 committee

• Institute of Electrical and Electronics Engineers
• All types of standards of Ethernet
• Copper and fiber

Deciphering the Standard

Speed signal, and media

• All contained in the standard name, i.e., 1000BASE-T

The number is related to the network speed

• 1000 is commonly 1,000 megabits per second (or one gigabit/sec)
• 10G would be 10 gigabits per second

BASE (baseband)

• Single frequency using the entire medium
• Broadband uses many frequencies, sharing the medium

Media type

• T is twisted pair copper, F is fiber
• SX would be short wavelength light

Optical Fiber

Fiber Communication

Transmission by light

• The visible spectrum

No RF signal

• Very difficult to monitor or tap

Signal slow to degrade

• Transmission over long distances

Immune to radio interference

• There’s no RF

Multimode fiber

Short-range communication

• Up to 2 km

Inexpensive light source

• i.e., LED

Single-mode Fiber

Long-range communication

• Up to 100 km without processing

Expensive light source

• Laser beams

Copper Cabling

The importance of cable

Fundamental to network communication

• Incredibly important foundation

Usually only get one good opportunity at building your cabling infrastructure

• Make it good!

The vast majority of wireless communication uses cables

• Everything eventually touches a cable

Twisted pair copper cabling

Balanced pair operation

• Two wires with equal and opposite signals
• Transmit+, Transmit-/Receive+, Receive-

The twist is the secret!

• Keep single wire constantly moving away from the interference
• The opposite signals are compared on the other end

Pairs in the same cable have different twist rates

Cable Speeds

Cables don’t have a speed

• The copper just sits there

Electrical signals are sent over copper cable

• The signal encoding determines the data transfer rate

A cable must be manufactured to specific standards

• IEEE 802.3 Ethernet standards determine the cable type

Cable standards are described as a “category” of cable

• Category 6, Category 7, etc.
• Check the IEEE standard to determine the minimum cable category
• The minimum cable category for 1000BASE-T is Category 5

Coaxial Cables

Two or more forms share a common axis

RG-6 used in television/digital cable

• And high speed Internet over cable

Twinaxial Cable

Two inner conductors

• Twinax

Common on 10 Gigabit Ethernet SFP+ cables

• Full duplex
• Five meters
• Low cost
• Low latency compared to twisted pair

Plenum space

No Plenum

Plenum

Plenum-rated Cable

Traditional cable jacket

• Polyvinyl chloride (PVC)

Fire-rated cable jacket

• Fluorinated ethylene polymer (FEP) or low-smoke polyvinyl chloride (PVC)

Plenum-rated cable may not be flexible

• May not have the same bend radius

Worst-case planning

• Used in plenum and risers
• Important concerns for any structure

Network Transceivers

Transmitter and receiver

• Usually in a single component

Provides a modular interface

• Add the transceiver that matches your network

Many types

• Ethernet or Fiber Channel
• Not compatible with each other

Different media types

• Fiber and copper

SFP and SFP+

Small Form-factor Pluggable (SFP)

• Commonly used to provide 1 Gbit/s fiber
• 1 Gbit/s RJ45 SFPs also available

Enhanced Small Form-factor Pluggable (SFP+)

• Exactly the same physical size as SFPs
• Supports data rates up to 16 Gbit/s
• Common with 10 Gigabit Ethernet

QSFP

Quad Small Form-factor Pluggable

• 4-channel SFP = Four 1 Gbit/s = 4 Gbit/s
• QSFP+ is four-channel SFP+ = Four 10 Gbit/sec = 40 Gbit/sec

Combine four SFPs into a single transceiver

• Cost savings in fiber and equipment

Transceiver Comparison

Fiber Connectors

SC — Subscriber Connector

Not actually an abbreviation

• We’ve created our own names
• Square Connector
• Standard Connector

Pushes on to lock

• Pull connector to unlock

A popular fiber connector

• Common in many data centers

Two SC connectors are combined in one.

LC — Local Connector

Another popular fiber type

• Smaller and more compact connector

Locks in place with a clip

• Press to release

Other names

• Lucent Connector
• Little Connector

Two LC connectors are combined here in pair.

ST — Straight TIP

Bayonet connector

• Stick and Twist

Push on and turn

• Locks in place
• Turn to unlock

MPO — Multi-fiber Push On

Twelve fibers in a single connector

• Save space and manage one cable

Push to lock in place

• Pull connector to unlock

May also see the MTP abbreviation

• A Corning brand
• The MTP MPO connector

Copper Connectors

RJ11 Connector

Registered Jack type 11

• 6 position, 2 conductor (6P2C)

Telephone & DSL connection

RJ45 Connector

Registered Jack type 45

8 positions, 8 conductors (8P8C)

• Modular connector
• Ethernet

F-connector

Coaxial cable

• Standard connector type
• Threaded connector

Cable television infrastructure

• Cable modem
• DOCSIS (Data Over Cable Service Interface Specification)

BNC Connector

Bayonet Neil-Concelman

• Paul Neil (Bell Labs) and Carl Concelman

Another common coaxial cable connector

• Common with twinax and DS3 WAN links
• Video connections

Secure connections

• Twist and lock in place