Physical Installations

Installing Networks

Distribution Frames

Passive cable termination

  • Punch down blocks
  • Patch panels

Usually mounted on the wall or flat surface

  • Uses a bit of real-estate

All transport media

  • Copper, fiber, voice, and data

Often used as a room or location name

  • It’s a significant part of the network

Main Distribution Frame (MDF)

Central point of the network

  • Usually in a data center

Termination point for WAN links

  • Connects the inside to the outside

Good test point

  • Test in both directions

This is often the data center

  • The central point for data

Intermediate Distribution Frame (IDF)

Extension of the MDF

  • A strategic distribution point

Connects the users to the network

  • Uplinks from the MDF
  • Workgroup switches
  • Other local resources

Common in medium to large organizations

  • Users are geographically diverse

Equipment racks

Rack sizes

  • 19" rack/device width

Height measured in rack units

  • 1U is 1.75"
  • A common rack height is 42U

Depth can vary

  • Often determined by the equipment

Plan and locate

  • Devices follow standard sizing

Cooling a data center

Heating, Ventilating, and Air conditioning

  • Thermodynamics, fluid mechanics, and heat transfer

A complex science

  • Not something you can properly design yourself
  • Must be integrated into the fire system

Data centers optimize cooling

  • Separate aisles for heating and cooling

Heat intake and exhaust is important

  • Front, back, or side

Cale infrastructure

Copper patch panel/patch bay

Punch-down block on one side

  • RJ45 connector on the other

Move a connection around

  • Different switch interfaces

The run to the desk doesn’t move

Fiber Distribution Panel

Permanent fiber installation

  • Patch panel at both ends

Fiber bend radius

  • Breaks when bent too tightly

Often includes a service loop

  • Extra fiber for future changes
  • Inexpensive insurance

Locking Cabinets

Data center hardware is usually managed by different groups

  • Responsibility lies with the owner

Racks can be installed together

  • Side-to-side

Enclosed cabinets with locks

  • Ventilation on front, back, top, and bottom

Power

WARNING

Always disconnect from the power source when working on a device

  • Always. Seriously.

Some devices store a charge in capacitors

  • Know how to discharge before touching

Never connect your body to any part of an electrical system

  • Do not connect yourself to the ground wire of an electrical system

Respect electricity

  • It doesn’t respect you

Amp and Volt

Ampere (amp, A) — The rate of electron flow past a point in one second

  • The diameter of the hose

Voltage (volt, V) Electrical “pressure” pushing the electrons

  • How open the faucet is
  • 120 volts, 240 volts

Watt

Watt (W)

  • How much energy is being consumed?
  • Electrical load is measured in watts

Easy to calculate

  • Volts × amps = watts
  • 120 V × 0.5 A = 60 W

Current

Alternating current (AC)

  • Direction of current constantly reverses
  • Distributes electricity efficiently over long distances

Frequency of this cycle is important

  • US/Canada – 110 to 120 volts of AC (VAC), 60 hertz (Hz)
  • Europe — 220-240 VAC, 50 Hz

Direct current (DC)

  • Current moves in the one direction with a constant voltage

Device power supplies

Devices commonly use DC voltage

  • Most power sources provide AC voltage

Convert 120 V AC or 240 V AC

  • To DC voltages

You’ll know when this isn’t working

  • An important component

UPS

Uninterruptible Power Supply

  • Short-term backup power
  • Blackouts, brownouts, surges

Common UPS types

  • Offline/Standby UPS
  • Line-interactive UPS
  • On-line/Double-conversion UPS

Features

  • Auto shutdown, battery capacity, outlets, phone line suppression

Power distribution units (PDUs)

Provide multiple power outlets

  • Usually in a rack

Often include monitoring and control

  • Manage power capacity
  • Enable or disable individual outlets

Environmental Factors

Humidity

We use a lot of power for data centers

  • One estimate is nearly 2% of all U.S. power consumption

Humidity level

  • High humidity promotes condensation
  • Low humidity promotes static discharge

Industry guidelines for data centers

  • Somewhere around 40% to 60% humidity
  • Specific settings vary on location and equipment type

Temperature

Electrical equipment has an optimal operating temperature

  • Usually part of the device specifications
  • Industry best practices are around 64 °F (ca. 18 °C) to 81 °F (ca. 27 °C)

Many external influences

  • Outdoor temperature
  • Temperature increases as system load increases

HVAC is used to manage temperature and humidity

  • Sensors are placed in strategic locations

Fire suppression

Data center fire safety

  • Large area, lots of electronics
  • Water isn’t the best fire suppression option

Common to use inert gases and chemical agents

  • Stored in tanks and dispersed during a fire
  • Many warning signs

Integrated into HVAC system

  • Monitor for carbon monoxide
  • Enable/disable air handlers