Guide–33

Guideline for Equipment Connections of

Intra-Equipment Rack and Inter-Equipment Rack

in

Central Data Centre

Source of Experience Sharing: Tony Kwong, KL Lee, Wing Lai, HY Liong (OPT)

Prepared by: Wing Lai (OPT) Date of Preparation: February 19, 2015

Revised by: HY Liong (OPT) Date of Revision: August 12, 2020

Verified by: Tony Kwong (OPT) Date of Verification: August 12, 2020

File: U:\OPSINT\DOC\OPSGUIDE\GUIDE-33 (Guideline for Equipment Connections of Intra-Equipment Rack and Inter-Equipment

Rack in Central Data Centre).pdf

Table of Contents

Content Page

1. Supporting Information to Achieve the Objectives 1

2. Tools 3

3. Equipment Installation Sequence in Equipment Rack (General Practices) 5

3.1 Zoning of Equipment Installation for Intra-Equipment Rack 5

3.2 General Operational Practice of Equipment Installation Sequence

for Intra-Equipment Rack

5

4. Cable Management of Data Cable Connections for Intra-Equipment Rack 7

4.1 Appropriate Conditions of Data Cable for Intra-Equipment Rack 7

4.1.1 Appropriate Conditions of UTP Cable for Intra-Equipment Rack

4.1.2 Appropriate Conditions of Fiber Cable for Intra-Equipment Rack

4.2 Labelling Location at the Two Ends of Data Cables 8

4.3 Information on the Data Cable Label 8

4.4 Collect UTP Cable by using Cable Ring 9

4.5 Collect Fiber Cable by using Cable Management Bend Radius Clip 9

4.6 Cover the Front RU Space which is occupied by Data Cable by using cable pass-

thru brush strips

9

4.7 Type and Format of Label applied to Data Cable 10

4.7.1 Turn Tell Label

5. Cable Management of Power Cord for Intra-Equipment Rack 11

5.1 Appropriate Conditions of Power Cord for Intra-Equipment Rack 11

5.1.1 C13-C14 and C19-C20 Power Cord

5.1.2 Non C13-C14 and C19-C20 Power Cord

5.1.3 Patching Preference of Power Cord connecting to Rack Power Distribution

Unit (PDU) for Intra-Equipment Rack

5.2 Labelling and Information of Power Cord for Intra-Equipment Rack 15

6. Cable Patching Preference for Intra-Network Equipment Rack 16

6.1 Patching Preference of Data Cables for Intra-Network Equipment Rack 16

7. Cable Patching Preference for Intra-Equipment Rack and Inter-Equipment Rack 17

7.1 Patching Preference of Data Cable for Intra-Equipment Rack 17

7.2 Patching Preference of Data Cable for Inter-Equipment Rack in CDC1 18

7.3 Patching Preference of Data Cable for Inter-Equipment Rack in CDC2 19

Table of Contents

8. Warmest Reminder 20

9. Titbits 23

9.1a Problems of Network Cables and Power Cables Jam 23

9.1b Network Cables and Power Cables are laid at side panel 23

9.2a Problems of Tension of Fiber Cables and Bending Angle 24

9.2b UTP and Fiber Cable Management 24

9.3a Problems of Surplus Cables 25

9.3b Surplus Cables are collected and placed tidily at the bottom of the

Intra-Equipment Rack

25

9.4a Direction of laying network cables 26

1. Supporting Information to Achieve the Objectives

Page 1

Background of the Work

An organization can invest in the best cables (twisted pair and fiber) and hardware in a

data centre but if they are not installed properly, they will not work or they will not work

well.

Protect the investment and follow the guidelines by means of exercising the important

practices as follows can make better use of the I.T. assets.

1. Bend Radius of the Cables - If we bend the twisted-pair cables too much, we loosen the twists and lose their

performance.

- If we bend the fiber too much, we will break the cables and cause failures.

2. Tension of the Cables

- Too much tension will be a headache.

- The pair twists (twisted pair cables) are responsible for much of the performance of the

cables.

- Pulling too hard untwists the pairs and loses the performance of the cable.

- Pulling too hard on the fiber will cause connection failures.

- Use supports and trays in cable runs to minimize sagging which pulls on the pairs or the

fiber connections and degrades performance.

3. Cinching/Wrapping of the Cable Bundles

- Not to cinch or wrap the cable bundles tightly which causes force and breaks the fiber

or degrades the performance of the twisted pair cables.

- Tie cable bundles loosely.

- Keep cable wraps snug but do not pull or crush cables.

4. Air Flow

- If different types of cables (power and data cables) are inadequately mounted in the

equipment racks, they will block the cool air intake and hot air exhaustion paths around

the equipment rack. It will create the ventilation problem between the ambient

temperature and the inner part of the equipment rack.

- Good cable management for the equipment rack can minimize the chance of

accumulating the cables at the ventilation area of the equipment rack.

5. Weight Balancing for the Loads in the Rack

6. Concerns of safety for moving the heavy machines and equipment in the Central

Data Centre

- Special care should be taken when you need to lift or lower the equipment and loads

in the rooms.

- In all possible circumstances, you should consider handling the load with handling aids

and in team where the situation is possible and applicable.

Actions you should do whenever necessary: Contact the on-duty staff of the Central Operations Team (OPT) to assess the situation and

check for using or operating the handling aids, where applicable.

7. Miscellaneous Considerations

- Visually inspect the cable installation for proper terminations, bend radius, tension and

cinching and etc.

Reference Material for Some of the Above Points: BLACK BOX NETWORK SERVICES: Guide to Structured Cabling

1. Supporting Information to Achieve the Objectives

Page 2

Points for Consideration When Purchasing the Equipment Which Will Be Installed in the

Equipment Racks of the Central Data Centre

The following points for consideration, when purchasing the equipment which will be

installed in the equipment racks of the Central Data Centre, can help facilitate the cable

management process in a more effective and efficient way.

1. It is highly suggested that the person, who plans to install the equipment in the

equipment racks of the Central Data Centre, contact the computer supervisors of

the Central Operations Team (OPT) as early as possible prior to placing the

purchase order of the equipment for better co-ordination and arrangement at the

project initial stage. (Note A)

2. When there will be lots of data cables connecting to the equipment that will be

purchased, it is highly suggested that cable management accessories such as

cable ring or cable guide for the equipment are to be equipped.

3. Hoping for a better cable management process, it is suggested that data cables

are to be laid at the rear of the equipment racks. It is suggested to install the

network port sides of the equipment at the rear of the equipment racks and match

the power supplies of the equipment with front-to-back air flow or back-to-front air

flow according to the real conditions of the equipment racks.

4. Hoping for a better air flow management process for the equipment racks, it is

highly suggested that appropriate lengths of power cords and data cables of the

equipment are to be used.

5. In order to increase the reliability of electrical power to the equipment, it is

suggested that the equipment are to be equipped with dual power supplies or

they are equipped with Automatic Transfer Switch (ATS) or etc for those single

power supply equipment.

6. For details and thorough planning, it is highly suggested that the project planner

refers to Note A for getting helps from OPT.

2. Tools

Page 3

1. HP rubber bend

2. Red cable tie

3. Green cable tie

4. Velcro tape

5. Panduit Panther LS8EQ Label Printer

6. Panduit Flag Label Cassette

2. Tools

Page 4

7. Cable Ring

8. Panduit Cable Management Bend Radius Clip

9. Panduit 19” Front And Rear 1RU Rack Mount Cable Management Panel

10. Ezibrush 19” Cable Pass-thru Brush Strips

3. Equipment Installation Sequence in Equipment Rack (General Practices)

Page 5

3.1 Zoning of Equipment Installation for Intra-Equipment Rack

For better air cooling and structure cabling, there are divided five zones for intra-rack equipment installation in each

equipment rack:

1. Zone 1 : Mainly to collect and keep the connected surplus cables.

2. Zone 2 : First priority to reserve the RU space to install equipment.

3. Zone 3 : Should be applied on condition that Zone 2 are fully occupied.

4. Zone 4 : First priority to reserve the RU space to install intra-rack network equipment.

5. Zone 5 : Reserved for INFRABOX (Door Access System) in each equipment rack where the INFRABOX is being

planned to use or it is readily to be installed to the equipment rack.

Note:

1. For consideration of load and weight balancing and safety concern of each equipment rack, it is recommended that

equipment with size over or equal to 3 RUs should be mounted from lower space in the equipment rack.

And it is highly recommended that server lift for the movement of equipment, such as equipment installation, relocation, etc.

is to be used.

3.2 General Operational Practice of Equipment Installation Sequence for Intra-Equipment Rack

3. Equipment Installation Sequence in Equipment Rack

(General Practices)

Page 6

Zone

KVM Switch / Console

42

41

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

09

08

07

06

05

04

03

02

01

Zone 04(For Intra-Rack

Network

Equipment)

Zone 03(Should be applied

when the RU space

of Zone 2 are fully

occupied)

Zone 02(Should be

occupied with the

first priority

for the Equipment

Installation)

Zone 01(For Collection and

keeping of

connected Surplus

Cable)

42 Rack Unit Equipment Space

Zone 05(For INFRABOX only)

Equipment Installation Sequence

42

41

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

09

08

07

06

05

04

03

02

01

Note:

Please consult Central Operations Team (OPT) for appropriate arrangement before equipment installation

in equipment rack in case both of Zone 02 and Zone 03 in the equipment rack are fully occupied.

4. Cable Management

of Data Cable Connections for Intra-Equipment Rack

Page 7

4.1 Appropriate Conditions of Data Cable for Intra-Equipment Rack

4.1.1 Appropriate Conditions of UTP Cable for Intra-Equipment Rack

It is preferred that using the UTP cable with

appropriate length (Please refer to the table 4.1.1.1)

for connection between different kind of equipment

in equipment rack.

Cable connection cross three zone

It is suggested that using 7/15 feet UTP cable for the

connection.

Cable connection cross two zone

It is suggested that using 3/5 feet UTP cable for the

connection.

Cable connection within one zone

It is preferred that using 3 feet UTP cable for the

connection.

Table 4.1.1.1: Suggestion of appropriate cable length in feet for keeping good air flow on cable patching

Zone04 Zone 03 Zone 02 Zone 01

Zone 04 3 3 / 5 5 / 7 7 / 15

Zone 03 3 / 5 3 3 / 5 5 / 5

Zone 02 5 / 7 3 / 5 3 3 / 5

Zone 01 7 / 15 5 / 7 3 / 5 3

4.1.2 Appropriate Conditions of Fiber Cable for Intra-Equipment Rack

It is preferred that using the fiber cable with appropriate length (Please refer to the table 4.1.1.1) for connection between different kind of equipment in equipment rack. It is suggested to prevent the acute or sharp bending angle of the fiber cable. During the process of patching fiber cable, the turning point should be protected by cable wrapping or tubing.

Parties who have to work on the equipment rack must keep the air flow of the equipment rack in a good condition. Otherwise, should Central Operations Team (OPT) find any situation violates the guideline; special task force of OPT will request the responsible parties to rectify it. For any concern about the guideline, please contact OPT: By email: opst1@itsc.cuhk.edu.hk, tongkaikwong@cuhk.edu.hk & tonykwong@cuhk.edu.hk Via phone: 3943 8819

4. Cable Management

of Data Cable Connections for Intra-Equipment Rack

Page 8

4.2 Labelling Location at the Two Ends of Data Cables

It is preferred that the following conditions are applied to entire cable labelling process.:

- Two ends of data cable must be labelled.

- The neccessary information into turn tell label and stick the label to the two ends of the data

cable.

- The necessary information marked on turn tell label must be the same on the both ends of

data cable.

- It is preferred to use OPT number or Asset Tag number in the entire cable labelling process.

- Hostname only be used when the equipment have never been assigned to a OPT number or

Asset Tag number.

4.3 Information on the Data Cable Label

Refer to upper diagram, the information of the label are shown as below:

Type 1: For Equipment (A) to Equipment (B)

Equipment (A)’s Asset Tag Number Port Number

Equipment (B)’s Asset Tag Number Port Number

Type 2: For Equipment (A) to Network Switch

Equipment (A)’s Asset Tag Number Port Number

Network Switch’s Asset Tag Number Port Number

Type 3: For Equipment (A) to Patch Panel Port

Equipment (A)’s Asset Tag Number Port Number

Patch Panel and Patch Panel Port Number

Type 4: For Patch Panel Port to Network Switch

Patch Panel and Patch Panel Port Number

Network Switch’s Asset Tag Number Port Number

4. Cable Management

of Data Cable Connections for Intra-Equipment Rack

Page 9

4.4 Collect UTP Cable by Using Cable Ring

It is preferred that using cable ring to collect UTP cable which is patched to

equipment.

4.5 Collect Fiber Cable by Using Cable Management Bend Radius Clip

It is preferred that using Cable Management Bend Radius Clip to collect fiber

cable which is patched to equipment.

4.6 Cover the Front RU Space which is occupied by Data Cable by using

Cable Pass-thru Brush Strips

It is preferred that using cable pass-thru brush strips at the following condition in

front of the equipment rack:

- Cable is patched from front to rear through an empty RU space

4. Cable Management

of Data Cable Connections for Intra-Equipment Rack

Page 10

4.7 Type and Format of Label applied to Data Cable

The two ends of the data cable must be labelled. The information on the two ends is

used for identification and verification purpose.

4.7.1 Turn Tell Label for UTP cable and Fiber Cable

Format and application for Turn Tell Label:

Printer: PANDUIT Panther LS8EQ Label Printer

Size: 8

Style: Bold

Used on: UTP Cable, Fiber Cable

5. Cable Management

of Power Cord for Intra-Equipment Rack

Page 11

5.1 Appropriate Conditions of Power Cord for Intra-Equipment Rack

5.1.1 C13-C14 and C19-C20 Power Cord

1. It is preferred that using C13-C14 or C19-C20 power cord for power

connection between equipment and power distribution unit (PDU).

C13-C14 Power Cord C19-C20 Power Cord

2. It is preferred that black color power cord is used in CDC1.

3. It is preferred that red cable tie are tied to both end of power cord

which connected to PDU’s socket with UPS-1 power supply in CDC1.

4. It is preferred that green cable tie are tied to both end of power cord

which connected to PDU’s socket with UPS-2 power supply in CDC1.

Red and Green cable tie used in power cord in CDC1

5. It is preferred that using orange color power cord for power

connection with MCB-A, MCB-C & RPDU-E supply in CDC2.

6. It is preferred that using blue color power cord for power connection

with MCB-B, MCB-D & RPDU-F supply in CDC2.

7.

Blue and Orange color power cord used in CDC2

5. Cable Management

of Power Cord for Intra-Equipment Rack

Page 12

5.1.2 Non C13 / C14 Power Cord

1. It is preferred that using black color BA1363 / C13 power cord for

power connection where it is necessary in CDC2.

Black color BA1363 / C13 power cord used in CDC2.

5.1.3 Patching Preference of Power Cord connecting to Rack

Power Distribution Unit (PDU) for Intra-Equipment Rack

1. It is preferred that power connection between equipment with single

feed is:

- Connected to PDU’s socket with UPS-2 power supply in CDC1.

- Connected to the socket with lower power consumption or more

power sockets are available in that PDU in CDC2 except High

Power Racks.

2. It is preferred that power connection between equipment with multi

feed are:

- Evenly connected to the PDU’s socket with UPS-1 and UPS-2

power supply in CDC1.

- Evenly connected to the PDU’s socket with MCB-A and MCB-B

power supply in CDC2 Phase 1.

- Evenly connected to the PDU’s socket with MCB-C and MCB-D

power supply in CDC2 Phase 2.

3. It is preferred to use 0.5m Power Cord to connect equipment and

PDU.

4. It is preferred to consult Central Operations Team (OPT) to provide 1m

power cord if the appropriate length of power cord is more than

0.5m.

5. For minimizing the length of the connected surplus power cord, it is

preferred that the power cord is to be connected to the nearest

power socket in the power distribution unit in the actual circumstance

inside the equipment rack.

5. Cable Management

of Power Cord for Intra-Equipment Rack

Page 13

6. It is suggested that the connector side of power cord is fixed to

machine with Velcro tape or cable tie where it is applicable.

Plug and Connector on C13 / C14 power cord

Example for the connector side of power cord fixed with Velcro tape

7. It is suggested that the plug side of power cord is fixed to PDU with

rubber band where it is applicable.

5. Cable Management

of Power Cord for Intra-Equipment Rack

Page 14

Example for the plug side of power cord fixed with Rubber Band

8. It is preferred that power cords be laid on the side panel / cable tray

at the side of the equipment rack with Velcro tape or cable tie.

Power cord laid on two side panel with Velcro tape and cable tie

9. It is preferred that all cabling at the rear side of the equipment rack

does not block the flow of exhausted air.

5. Cable Management

of Power Cord for Intra-Equipment Rack

Page 15

5.2 Labelling and Information of Power Cord for Intra-Equipment Rack 1. It is preferred that both ends of power cords should be labelled with turn tell

lablel in CDC1.

2. It is preferred that the information on turn tell lable includes OPT number or Asset

Tag number , PDU name and socket number (if available), for example:

HW19065211

3R.4.7

Example for the information in cable marker tie

Example for turn tell lable used on power cord.

3. It is not required to label the power cords in CDC2.

6. Cable Patching Preference

for Intra-Network Equipment Rack

Page 16

6.1 Patching Preference of Data Cables for Intra-Network Equipment Rack

6.1.1 It is preferred that data cables are laid on cable tray at the side of the intra-

network equipment rack with Velcro tape.

(Please refer to “A” in the blow photo).

6.1.2 The side of cable laying depends on which side of switch port to be patched.

(Please refer to “B” in the blow photo).

Cable Patching in Intra-Network Equipment Rack

7. Cable Patching Preference

for Intra-Equipment Rack and Inter-Equipment Rack

Page 17

7.1 Patching Preference of Data Cable for Intra-Equipment Rack

7.1.1 It is preferred that data cables are laid on the side panel / cable tray at the side of

the intra-equipment rack with Velcro tape or cable tie

(Please refer to “A” in the blow photo).

7.1.2 The side of cable laying depends on which side of equipment port to be patched

(Please refer to “B” in the blow photo).

Front of Intra-Equipment Rack

Rear of Intra-Equipment Rack

7. Cable Patching Preference

for Intra-Equipment Rack and Inter-Equipment Rack

Page 18

7.1.3 If the connection port of equipment is at the front side of the equipment rack,

1RU space is reserved for cable management.

7.2 Patching Preference of Data Cable for Inter-Equipment Rack in CDC1

Type of cable using

Two Equipment racks at

Inter-Rack Connection

Fiber Cable UTP Cable

Intra-row (Same row) It is preferred that fiber cable is

laid inside the fiber cable

basket at the top of equipment

rack.

Refer to “A” on the photo below.

It is preferred that UTP cable is

laid at the top of inter-

equipment rack but outside

Fiber Cable Basket.

Refer to “B” on the photo below.

Inter-row (Different

row)

To be discussed between

computer supervisor of Central

Operations Team (OPT) and the

requester first.

Under the raised floor

If the real situation is not allowed to lay the cable at the top of the equipment rack or Fiber

Cable Tray, the network cable should be laid under the raised floor.

7. Cable Patching Preference

for Intra-Equipment Rack and Inter-Equipment Rack

Page 19

7.3 Patching Preference of Data Cable for Inter-Equipment Rack in CDC2

7.3.1 It is not suggested to lay multi-mode fiber patch cord through cable basket which

is over inter-equipment rack in CDC2.

It is suggested to make use of the patch panel in intra-equipment racks to make a

network connection of equipment between inter-equipment rack

or

it is suggested to place an order to service provider to install enough patch panel

port if necessary.

(For detail, please discuss with Computer Supervisor of Central Operations Team.)

7.3.2 The cable basket over inter-equipment rack in CDC2 is for ITSC’s copper cables

use except the fiber/UTP cables that have been laid by service provider.

8. Warmest Reminder

Page 20

8.1 Surplus cable tie’s tail should be cut clearly.

With surplus cable tie’s tail

Without surplus cable tie’s tail

8.2 Cable marker tie should be turned toward to the face for easy

reading.

8.3 Surplus connected cable should be collected and placed tidily on

the bottom of the equipment rack (Zone 1).

8. Warmest Reminder

Page 21

8.5 Cover the fiber cable connectors all the time when not in use.

8.4 For minimizing the ventilation and cable management problems, it is

not preferred to install Cable Management Arms at the rear of the

equipment.

8. Warmest Reminder

Page 22

8.6 A notice is attached at the door of network cable cabinet

9. Titbits

Page 23

9.1a Problems of Network Cables and Power Cables Jam

9.1b Network Cables and Power Cords are laid at Side Panel

9. Titbits

Page 24

9.2a Problems of Tension of Fiber Cables and Bending Angle

9.2b UTP and Fiber Cable Management

9. Titbits

Page 25

9.3a Problems of Surplus Cables

9.3b Surplus Cables should be collected and placed tidily at the

bottom of the Intra-Equipment Rack

9. Titbits

Page 26

9.4a Direction of laying network cables

9. Titbits

Page 27

9.5a Problems of Fiber Optics Cables Jam.

Bending a fiber optic cable excessively may cause the optical signal to

refract and escape through the cladding. It could also cause permanent

damage by creating micro cracks on the delicate glass fibers. And when

overbending interferes with light transmission, the resulting increased

attenuation compromises the integrity of your valuable data. So, always

remember that do not bend the fiber beyond it’s specified fiber bend radius.

9. Titbits

Page 28

9.5b The diagram to the illustrates a cable no smaller than a fourteen-

centimetres bend radius.

https://en.wikipedia.org/wiki/Bend_radius#Fiber_optics

9.5c It is suggested to use Cable Management Bend Radius Clip to collect fiber cable

which is patched to equipment & cause the Fiber cable bending radius.

9. Titbits

Page 29

9.5d It is suggested to use Cable Management Bend Radius Clip to collect fiber cable

which is patched to equipment & cause the Fiber cable broken.

9.5e It is suggested to use Cable Management Bend Radius Clip to collect fiber cable

which is patched to equipment.

9. Titbits

Page 30

9.5f Cable Management Bend Radius Clip is in used.

9. Titbits

Page 31

9.6a How to Install an SFP+ Optical Transceiver Module correctly.

What is GBIC?

GBIC stands for Giga Bitrate Interface Converter. The design can be used for hot plug,

SC interface (subscriber connector).

What is SFP?

SFP stands for Small Form-Factor Pluggable, can be simply considered as an upgraded

version of GBIC. SFP module is much smaller than GBIC module, you can have more

interfaces on the same line card or switch.

1. Remove the protective end cap for the optical transceiver.

2. Pull the locking handle into the full horizontal position until you feel the handle click into

position.

3. Holding the optical transceiver (SFP+ module) by the edges, align the SFP+ module with

the slot and slide it into the opening.

4. Applying even pressure at both corners of the SFP+ module, push the module until it is

firmly seated in the slot. 5. Push the handle up to the vertical position to lock the SFP+ module in place.

9. Titbits

Page 32

The LC connector and SFP+ receptacles are keyed for proper fitting.

9. Titbits

Page 33

9.7a Collect UTP Cable by Using Cable Ring

It is preferred to use cable ring to collect UTP cable which is patched to

equipment.

9.7b It is preferred to use UTP cable management panel to collect UTP

cable which is patched to equipment where necessarily.

9. Titbits

Page 34

9.7c Cover the Front RU Space which is occupied by Data Cable by using Cable

Pass-thru Brush Strips.

It is preferred that using cable pass-thru brush strips at the following condition in

front of the equipment rack:

- Cable is patched from front to rear through an empty RU space -

9.7d Network Cables must be laid on top at both sides of the network device.

9. Titbits

Page 35

9.7e How to Reverse the Polarity of LC Switchable Uniboot Cable.

9. Titbits

Page 36

How to Reverse the Polarity of LC Switchable Uniboot Cable?

To reverse polarity, you just need three steps. First, open the connector top. Second, switch the

polarity you need. At last, close the connector top. No tools are needed during the whole

process.

- End of Guideline -