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
IEEE Standard Description Media Network Speed
1000BASE-T Gigabit Ethernet Copper 1 gigabit per second
10GBASE-T 10 Gigabit Ethernet Copper 10 gigabits per second
1000BASE-SX Gigabit Ethernet Fiber 1 gigabit per second

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