1. Chap 8 Design and Documentation
Andres, Wen-Yuan Liao
Department of Computer Science and Engineering
De Lin Institute of Technology

2. Overview Network Design and Documentation
Document brainstormed ideas, problem solving matrices
Wiring closet specifications
Wiring and electrical techniques used in network building

3. Basic Network Design and Documentation
General design process
Network design issues
General network design process
Network design documents

4. General design process
Layer 1 design
A logical and a physical topology
Layer 2 LAN topology
Reduce congestion and collision domain size
Layer 3 topology
Break up both collision and broadcast domains.

5. Network design issues Gather information about the organization
Make a detailed analysis and assessment of the current and projected requirements
Identify the resources and constraints of the organization

7. Network design documents
Engineering journal
Logical topology/Physical topology
Cut sheets
Problem-solving matrices
Labeled outlets/Labeled cable runs
Summary of outlets and cable runs
Summary of devices, MAC addresses, and IP addresses

8. Wiring Closet Specifications
Overview of wiring closet selection
Size
Environmental specification
Walls, floors, and ceilings
Temperature and humidity
Lighting fixtures and power outlets
Room and equipment access
Cable access and support

9. Overview of wiring closet selection
MDF:Main Distribution Facility/Facilities IDF:Intermediate Distribution Facilities

13. Size
The horizontal cabling runs must be attached to a central point in a star topology
The central point is the wiring closet
Where the patch panel and the hub must be installed

14. Size TIA/EIA-569 A minimum of one wiring closet
Additional wiring closets for each 1,000 m2

16. Environmental specification
Power supply and heating/ventilation/air conditioning (HVAC) issues
Be secure from unauthorized access
Meet all applicable building and safety codes

17. Walls, floors, and ceilings
Bear the load
MDF: 4.8 kPA (100 lb/ft²)
IDF: 2.4 kPA (50 lb/ft²)
Raised floor
Accommodate incoming horizontal cables
Floor coverings should be tile

19. Temperature and humidity
Maintain a room temperature of approximately 21° C
No water or steam pipes running through or above the room, with the exception of a sprinkler system
Relative humidity should be maintained at a level between 30%-50%

20. Lighting fixtures & power outlets
A minimum of two dedicated, non-switched, AC duplex electrical outlet receptacles, each on separate circuits
Florescent lighting should be avoided for cable pathways because of the outside interference that it generates

21. Room and equipment access
The door of a wiring closet should be at least .9 m wide, and should swing open out of the room, thus ensuring an easy exit for workers
The lock should be located on the outside

22. Room and equipment access
Allow 48 cm for the panel to swing out from the wall
A distribution rack, then it must have a minimum 15.2 cm of wall clearance for the equipment, plus another cm for physical access by workmen and repairmen

23. Cable access and support
If a wiring closet serves as an MDF, all cable running from it should be protected by 10.2 cm conduit or sleeved core
All horizontal cabling that runs from work areas to a wiring closet should be run under a raised floor

24. Cable access and support
Any wall/ceiling openings that provide access for the conduit, or sleeved core, must be sealed with smoke and flame-retardant materials

26. Identifying Potential Wiring Closets
Topology as floor plan
Selecting potential locations
Determining number of wiring closets
Identification practice

27. In order to determine the location of a wiring closet
Topology as floor plan
In order to determine the location of a wiring closet
Drawing a floor plan of the building
Adding to it all of the devices that will be connected to the network
Computers, printers and file servers

30. Selecting potential locations
Identify secure locations that are close to the POP
The POP is where telecommunications services, provided by the telephone company, connect to the building's communication facilities

32. Determining number of wiring closets
Use your compass to draw circles: a radius of 50 m from potential hub locations
If overlap, eliminate one of the hub locations
To see if one of them is closer to the POP than the other(s)

34. Horizontal and Backbone Cabling
Catchment area problems
MDF location in a multi-story building
Example of where you would use multiple wiring closets
Cabling for MDF and IDF connections
Backbone cabling media
TIA/EIA-568-A requirements for backbone cabling
Maximum distances for backbone cabling

35. Catchment area problems
If the 100 m catchment area cannot provide enough coverage, it can be extended by using repeaters
100 Ohm UTP (four pair)
150 Ohm STP-A (two pair)
2 fiber (duplex) 62.5/125 µm optical fiber
Multimode optical fiber

37. MDF location in a multi-story building
The MDF is usually located on one of the middle floors of the building
The POP might be located on the first floor, or in the basement

40. Cabling for MDF and IDF connections
Backbone cabling: vertical cabling
Connect wiring closets to each other

41. Backbone cabling media
TIA/EIA-568-A
100 Ω UTP (four-pair)
150 Ω STP-A (two-pair)
62.5/125 µm multimode optical fiber
Single-mode optical fiber
The IDF is sometimes referred to as the horizontal cross-connect (HCC)
The MDF is sometimes referred to as the main cross-connect (MCC)

43. Only one

47. Electricity and Grounding
Differences between AC and DC
AC line noise
Electrostatic discharge
Grounding electrical current in computer equipment
Purpose of grounding computer equipment
Safety ground connections
Safety ground connection problems

48. Differences between AC & DC
DC flows at a constant value when circuits are turned on
AC rises and falls in current values

51. AC line noise Coming from a nearby video monitor, or hard disk drive
It does this by adding unwanted voltages to the desired signals
Prevent a computer's logic gates from detecting the leading and trailing edges of the square signal waves

53. Electrostatic discharge
ESDs can destroy semiconductors and data, in a random fashion, as they shoot through a computer
A solution that can help solve problems that arise from ESD is good grounding

54. Grounding electrical current in computer equipment
The safety ground wire is connected to any exposed metal part of the equipment
The motherboards and computing circuits in computing equipment are electrically connected to the chassis
This also connects them to the safety grounding wire, which is used to dissipate static electricity.

55. Grounding
Prevent such metal parts from becoming energized with a hazardous voltage
Circuit breakers and Ground Fault Circuit Interrupters (GFCIs)
Surge suppressors and Uninterrupted Power Supplies (UPS)
Be required to protect computing and networking equipment

57. Safety ground connection problems
The earth ground between buildings is almost never the same

58. Cabling and Grounding Causes of ground potential problems
Networking devices and dangerous circuits
Faulty ground wiring problems
Avoiding potentially dangerous circuits between buildings
How fiber optic cable can prevent electrical shocks
Reasons for using UTP for backbone cabling between buildings

59. Causes of ground potential problems
When devices with different ground potentials are linked in a circuit, they can produce hazardous shocks

60. Networking devices and dangerous circuits
The closed circuit produced by the use of UTP cable would then allow electrical current to flow from the negative source to the positive source
One hand rule
You should not use more than one hand at a time to touch any electrical device
The second hand should remain in your pocket

62. Avoiding potentially dangerous circuits between buildings
Use fiber-optic cable as the backbone
Because glass is an insulator rather than a conductor, electricity does not travel over fiber-optic cables

63. Reasons for using UTP for backbone cabling between buildings
Whenever copper is used for backbone cabling, it can provide a pathway for lighting strikes to enter a building

64. Network Power Supply Issues: Power Line Problems
Power problem classifications
Normal mode and common mode
Typical power line problems
Sources of surges and spikes
Surge and spike damage
Surge and spike solutions
Sag and brownout solutions
Oscillation solution

65. Power problem classifications
Normal mode problem
Exists between the hot and neutral wire
Do not, ordinarily, pose a hazard to you or to your computer
Be intercepted by a computer's power supply, an uninterruptible power supply or an AC power line filter

66. Power problem classifications
Common mode problem
If a situation involves either the hot, or neutral wire, and the safety ground wire
Go directly to a computer's chassis without an intervening filter.

67. Typical power line problems
Power disturbance
Unwanted voltage that is sent to electrical equipment
Include voltage surges, sags, spikes, and oscillations
Another situation that can cause power problems is a total power loss

69. Surge
A voltage increase above 110% of the normal voltage carried by a power line
A few seconds
Hardware damage
Most computer power supplies that run at 120 V are not built to handle 260 V for any length of time

71. Sag/Brownout A brownout that lasts less than a second
Voltage on the power line falls below 80% of the normal voltage
Caused by overloaded circuits

72. Spike An impulse that produces a voltage overload on the power line
Spikes last between .5 and 100 microseconds
In simple terms, when a spike occurs it means that your power line has momentarily been struck with a powerful hit of at least 240 V

74. Oscillations and Noise
Oscillations are also sometimes referred to as harmonics, or noise
A common cause of oscillation is an excessively long electrical wiring run, which creates an antenna effect.

76. Sources of surges and spikes
Probably the most common one is a nearby lightning strike
Utility switching operations performed by the local power company can also trigger electrical surges and spikes

77. Sources of surges and spikes
Inside your school, office, or building
Elevators, photocopiers, and air conditioners, cycle on and off, they create momentary dips and surges in power

78. Surge and spike solutions
Surge suppressors
When surges or spikes come in, surge suppressors divert them to ground
A good rule of thumb to follow is to protect all networking devices with surge suppressors

79. Surge and spike solutions
If you protect one networking device with a surge suppressor, then you should protect all devices, including the telephone line, in the same way

80. Sag and brownout solutions
Every network should have some type of uninterruptable power supply

81. Oscillation solution
The best way to address the problem of oscillation is to rewire

82. Surge Suppressors and UPS Functions
Surge suppressors: networking device locations
Surge suppressors: for power panel locations
UPS: for certain LAN devices
UPS: for certain electrical problems
UPS: components
UPS: differences in UPS features
UPS: description and operation

83. Surge suppressors: networking device locations
Surge suppressors are usually mounted on a wall power socket, to which a networking device is connected
A device called a metal oxide varistor (MOV) is most often used as this type of surge suppressor

84. Surge suppressors: networking device locations
This type of surge suppressor has a limited lifetime, dependent, in part, on heat and usage

86. Surge suppressors: for power panel locations
By placing a commercial grade surge suppressor near the power panel, the impact on the network, of voltage surges and spikes diverted to ground, can be reduced

87. UPS: for certain electrical problems
An UPS is designed to handle only short-duration power outages
If a LAN requires uninterrupted power, even during power outages that could last several hours, then a generator would be needed to supplement the backup provided by a UPS

88. UPS: components Inverter battery charger
Convert low-level DC voltage of the batteries into the AC voltage, normally supplied by the power line, to networking devices
battery charger
Designed to keep the batteries in peak condition during periods when the power line system is functioning normally

89. UPS: components Batteries
Generally, the bigger the batteries in a UPS, the longer a period of time it will be able to support networking devices during power outages

92. UPS: description and operation
A good UPS should be designed to communicate with the file server
Shut down files when the UPS battery power nears its end
A good UPS reports instances when the server starts to run on battery power

93. Summary Document what you have done A wiring closet Backbone cabling
Surge suppressors