Transcript Chapter 8 – Cisco Semester I

Chapter 4 – Cisco Semester I
Wiring Closets
IDF and MDF
Metrics
Behavior Objective
• Stress importance of good documentation
• Stress adherence to wiring Do’s and Don’ts
–Students will document work
–Students will follow standard
procedures
Learning Objective
• Develop knowledge base to enable students
to design networks that perform well
Students will learn design
concepts
Students will gain confidence
completing wiring tasks
Content
• Network Design
• Topologies
– Logical
• Token Ring (single ring)
• FDDI (dual ring)
• Ethernet (logical bus) – largest % of installations
– Physical
• Star and Extended Star
– Both Ethernet and IEEE specify Star
» Extended Star requires additional wiring closets
Content Continued
• Wiring and electrical standards
– ANSI
– EIA/TIA 569-A
– ISO/NEC
• Wiring closet specifications
• Medium
– CAT 5 UTP for horizontal cabling
Why CAT 5 UTP
• Easy to use (not too thick but thick enough
to hold up – unlike cheap net)
• Twists provide cancellation effect
• Relatively inexpensive
– Specified by both IEEE and Ethernet
Ethernet Network Speeds
• 10Base T
• 100 Base TX (aka Fast Ethernet)
• 1000 Base T (aka Gigabit)
Documentation Required
• Organization Information
– Who will use, computer skill level, network knowledge
base, tasks performed
• Analysis and Problem Solving Information
Gathered
• Cut Sheet – diagram floor plans
• Logical Design Map – IP addresses
• Physical Design Map – MAC addresses (devices),
cable runs, outlets, etc.
DEVICES
• Layer 1
– Hubs, repeaters (extend run beyond 99 meters)
– Transceivers – connect unlike devices
• Layer 2
– Bridges -- reduce congestion and collision domain
– Switches – also provide virtual LAN and larger
bandwidth
• Layer 3
– Routers – segmentation – divide network into
segments; reduce broadcast domain
Ground Basics
• Grounds are critical
– Can minimize ESD problem
• Remember ESC can destroy semiconductors and data
• Safety ground can prevent high voltage buildup
• GFCI (Ground Fault Circuit Interrupt)can cause circuit breaker
to stop flow of electrons
• Grounds connected to chassis are not enough to
protect computers and networks
– Also need UPS (Uninterrupted Power Supply)
– And Surge Protector
Wiring Basics
• One Hand Rule
– Keep one hand in pocket when working with electrical
devices to avoid creating a circuit with your body as the
connection
• Electrical Current through the heart can kill
• Common Fault
– Hot Wire and Safety
• Normal Fault
– Hot Wire and Neutral Wire
Wiring Closet Specifications
• Near POP – to connect to outside world
• Centrally located – to minimize length of
horizontal cable runs
– More important than being near POP
• Large enough to allow for expansion
• Raised floor
– To bring in horizontal cabling from work areas
Wiring Closet Continued
• Tile Floor
– Reduce dust, minimize static electricity
• No Dropped Ceiling
– Security
• Fire-Rated Plywood on Interior Walls
– Minimize fire risk (1.9 cm thick – 4.4 cm from wall)
• Controlled Humidity (30-50%)
• Controlled Temperature (21 C or 70 F)
More Wiring Closet Specs
• .9 Meter door that opens to hall
– Locked from outside but controlled from inside
• 50 candle foot lighting (preferably not
fluorescent) – 2.6 meters above floor
• Light switch immediately inside door
• Two dedicated non-switched circuits
• Outlets every 1.8 meters (6 feet)
And Still More Closet Specs
• Ladder Rack to support Patch Panel
• Sufficient Floor Load capacity to bear
weight of devices
• Ceiling and wall openings sealed with fire
retardant material
Important Wiring Closet Info
• Need a wiring closet on every floor
• Need a wiring closet for every 1000 square
meters of floor space
• Maximum length of horizontal cabling is 90
meters
• Add 3 meters to attach work station and 6
meters to attach to patch panel
– Total length – approx 100 meters
Multiple Wiring Closets
Structured Wiring
• Designate primary wiring closet as MDF –
Multiple Distribution Facility
– Hubs and Patch Panel in MDF or IMF
– Routers, switches, WAN connection in MDF
• Floor load requirements higher than IDF
• Vertical cabling (Backbone) will connect
other wiring closets (IDF – Intermediate
Distribution Facility)
MDF and IDF Location
• Good location can minimize horizontal
cable runs
• Chosen location should minimize
environmental problems
• Chosen location should make it easy to
install and maintain network
Structured Wiring
• MDF known as Main Cross Connect
• Can have two levels of IDF (Intermediate)
• When there is only one level
– IDF Horizontal Cross Connect
• When there are two levels
– IDF connected to MDF is Intermediate Cross Connect
• Other IDFs connected to workstations are HCC
– There can be only one level between IDF for work stations and
MDF
MDF – IDF Cabling
• Aka Backbone Cabling
Between Buildings (InterBuilding) -- Single Mode
Fiber preferred – 3000 meters
Within Building (Intrabuilding)
MultiFiber 62.5/125 u is recommended (568A) – 2000
meters – USED MOST OFTEN
Other options (not preferred and not extensively used)
100 ohm UTP (four pair)
150 ohm STP (two pair)
Coaxial cable is not recommended
Why Fiber for Backbone?
• Eliminates Problems Caused By:
– Different Voltage Potential in circuits served by
different transformers (a grounding problem)
• Different transformers can serve circuits in same
building
– Electrical strikes that could hit cabling between
buildings
• Backbone includes connection to POP and
Wiring Closets (from Patch Cords)
Special Backbone Considerations
• Run wire through conduit or sleeve
• If unable to run under floor
– Run sleeve above door level
• Total distance from MDF to workstations
can’t exceed 3000 meters for single mode or
2000 for multimode fiber
Metric Reminder
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1 Meter is approximately 39.?? Inches
1 decimeter = 1/10 meter
1 centimeter = 1/100 meter
1 millimeter = 1/1000 meter
10 meters = 1 decameters
100 meters = 1 hectometer
1000 meters = 1 kilometer