JD Data Center Integrated Cabling Case Study

The structure of the integrated wiring system is closely related to the network architecture. Only when the network architecture is basically determined can the structure of the wiring system be determined. The network architecture and the transmission medium used will affect the design of the wiring system.

1. Data center requirements

The system is required to support the connection of computer network systems and video and voice communication systems to meet the needs of different systems. The system is highly modular and can be managed electronically. There is a reserve of various wiring points that meet the development scale requirements and facilitate expansion construction.

The specific requirements of the computer room are as follows:

(1) It is recommended to use Category 6 wiring system and OM3 10 Gigabit multimode fiber wiring system.

(2) Each cabinet is arranged with 32 copper cable points.

(3) The optical cable trunk is arranged from the head cabinet to the main distribution cabinet. The number of cores is determined according to the traffic demand, with a dual-route redundant structure and a certain amount of copper cable as backup.

(4) It is recommended to use the high-density IBM ACS integrated fiber connection system (FIT) for all optical fiber products.

(5) The wiring management system in the computer room needs to meet the following requirements:

◆ There is an in-cabinet jumper management mechanism (which can facilitate the management of jumpers and make them neat).

◆ Various interfaces are unified (copper cables are unified to RJ45 network interfaces, and optical fibers are recommended to be unified to duplex LC small interfaces).

◆ Convenient means of intercommunication and interconnection (the business relationships that may occur in each cabinet are clear).

◆ Meet wiring habits (such as telecommunications wiring, network wiring habits, etc.).

Data center design is recommended to have a certain degree of fire resistance: low-smoke halogen-free cables can be used to enable the system to have good performance in the event of a fire, including flame retardant (will not cause the fire to spread along the cables), low smoke (will not suffocate people in the fire), non-toxic (will not poison people in the fire), and non-corrosive (will not cause equipment corrosion). This not only meets the requirements of national standards, but also has practical fire prevention significance.

2. Data Center Design

According to the spatial division of the "Communication Infrastructure Standard for Data Centers" (TIA-942) promulgated in 2005, a data center should be divided into:

◆ Entrance Room (ER).

◆ Main Distribution Area (MDA).

◆ Horizontal Distribution Area (HAD).

◆ Zone Distribution Area (ZDA).

◆ Equipment Distribution Area (EDA).

The structure of the integrated wiring system is closely related to the network architecture. Only when the network architecture is basically determined can the structure of the wiring system be determined. The architecture and transmission medium used by the network will affect the design of the wiring system. Similarly, the star or tree topology of the integrated wiring system also makes the basic topology of the network star or tree.

It is recommended that the data center be divided into the following areas according to the needs of structured cabling:

(1) Network area: The network area is the core switching layer, aggregation layer, and network security of the entire central computer room. The general distribution area for telecommunications access and local area network realizes the separation of optical and copper and is responsible for the internal and external connections of the entire central computer room. Among them, the MDF of the building wiring system can also be set up here.

(2) PC server area: 24/32 UTPs are arranged in each cabinet as required, and X-core multi-mode 10G optical fibers are connected to the aggregation layer switches in the head cabinet. The aggregation layer switches in the head cabinet are connected to the aggregation layer port area of the MDA through the 10G multi-mode optical cable trunk.

(3) Small computer area: XX UTPs are arranged in each cabinet of the small computer, and XX-core optical cables in each cabinet are connected to the ground box, and then connected to the storage switch through the ground box, and then interconnected with the storage device.

(4) MDA distribution area: The MDA distribution area of this project is divided into LAN and SAN.

The LAN main distribution frame can be set up in the network equipment area, which is divided into network equipment port area, minicomputer port area, aggregation layer switch port area, building port area (building MDF), etc.

The SAN main distribution frame is set up in the network equipment area, which is divided into minicomputer port area, storage device port area, storage switching device port area, etc.

3. Products used in data centers

3.1 Pre-terminated optical cables

Pre-terminated optical cables are suitable for high-density applications in data centers. The number of cores can be from 4 to 144, and they are easy to install and move. The waterproof, dustproof, pressure-resistant and tensile-resistant protective sleeves at both ends can effectively ensure that the optical cable and optical fiber connector are not damaged during transportation and installation. The waterproof and dustproof protection of outdoor pre-connected optical cables reaches IP67 protection, and the indoor pre-connected optical cables reach IP50 protection, with a tensile force greater than 600N. The entire pre-connected optical cable does not have any fusion breakpoints in the middle and has been 100% strictly tested at the factory to ensure product performance, as shown in Figure 1.

Figure 1

In addition, pre-terminated optical cables also have the following features:

◆ Specially designed anti-rat bite optical cables.

◆ Can be moved / easy to maintain.

◆ High density / space saving.

◆ The manufacturer pre-installs various forms of connectors required by customers on both ends of the optical fiber before the product leaves the factory, and adds high-density protective accessories.

Pre-terminated optical cables fully comply with ISO/IEC 11801, TIA/EIA 568A/B, and EN50173 standards.

The line sequence of pre-terminated optical cables adopts universal polarity line sequence, and all use low-smoke halogen-free green environmentally friendly flame-retardant cables that meet the requirements of IEC60332-3 standards.

3.2 High-density patch panel

The optical fiber patch panel frame has reserved 12 (16K9400)/3 (16K9401) pre-connected optical fiber modules for plugging and unplugging, and each module has a corresponding slot. The cable storage slot on the back of the patch panel adopts a drawer-type structure. During installation, you only need to pull out the drawer and insert the pre-connected optical cable. The installation is quick and convenient. There is a label slot on the back of the optical fiber patch panel to facilitate the protection and management of label paper, as shown in Figure 2.

Figure 2

The high-density patch panel fully complies with ISO/IEC 11801, TIA/EIA 568A/B, and EN50173 standards.

3.3 Pre-terminated fiber optic module

The pre-terminated fiber optic module adopts an aluminum alloy shell design to effectively protect the internal fiber branch jumper, making the relatively fragile internal fiber optic components less susceptible to damage during installation and transportation. The number of pre-connected fiber optic modules can be flexibly configured according to user requirements, and installation and disassembly are convenient, which is also convenient for hardware upgrades. Pre-connected fiber optic modules are available in LC, MTRJ, SC or SC-DC modules according to the configuration of single-core or dual-core fiber optic adapters. Each module can provide 12-core or 24-core fiber optic connection density. The performance insertion loss of all fiber optic connectors meets the requirements of IEC 61300-3-4 standards, and all fiber optic connector end faces pass the three-dimensional test of geometric dimensions to ensure the reliability of the product, as shown in Figure 3.

Figure 3

The pre-terminated optical fiber module fully complies with ISO/IEC 11801, TIA/EIA 568A/B, EN50173, and IEC 61300-3-4 standards.

4. Key points for data center construction

4.1 Copper cable construction

(1) The horizontal cables and trunk cables in the machine room should be kept flat throughout the entire process, and each cable should not cross each other. The cables should be bent in a natural way at the corners and should not be scattered.

(2) Both ends of each cable (the wiring cabinet end and the terminal outlet end) must have the same, firm, clear, and unified numbering.

(3) The cable should be pulled out with a wiring margin of no less than 60cm at the terminal outlet, and the cable should be coiled and placed in the embedded box.

(4) If there is a lot of resistance during wiring and it cannot be pulled, be careful not to use too much force to prevent the cable core from breaking.

(5) When wiring, from the wiring cabinet to the terminal outlet, the cable must not be cut or connected anywhere in the middle, and there must be no breakpoints in the middle. A single cable must be laid in place.

(6) The cable should be laid straight, without twisting or looping, and should not be squeezed or damaged by external forces. Especially for optical cables, the radius of the turning point must be greater than ten times the radius of the cable (4 pairs of twisted pair cables must be greater than 10cm).

(7) When laying copper cables and optical cables in vertical cable ducts, it is required to tie them on the cable duct every 60cm.

(8) At the wiring cabinet, the cable wiring margin will be left according to the technical supervision opinions based on the floor conditions of each floor (generally, 6m is left after the cable enters the wiring cabinet).

(9) The cables in the cable duct should be bundled neatly, and the horizontal Category 6 twisted pair cables should be labeled to indicate the area or room where the bundle of twisted pair cables is used.

4.2 Optical cable construction

(1) If the optical cable and twisted pair are in the same cable duct,

the optical cable should not be placed at the bottom of the cable duct to avoid squeezing the optical cable. In vertical cable ducts, it is required to tie the cable duct every 60cm to prevent the weight of the optical cable from affecting it.

(2) For optical cables and large-pair twisted pair cables, a label should be affixed every 10m or so to mark the direction and number of the optical cable and large-pair twisted pair cables.

(3) When entering the management room, use floor bridge or upper bridge for wiring.

(4) Construction personnel should guide at each corner to prevent wear at the corner of the bridge.

(5) It is recommended to use nylon rope instead of plastic strapping tape for optical cable bundling.

(6) Optical cable laying is prohibited from having too small a bending radius.

4.3 Construction of high-density optical fiber system

(1) Conduct research and design before construction to avoid excessively long fiber coils under the floor and avoid losses caused by insufficient length of the optical cable trunk.

(2) Installation of the floor box: Pay attention to the connection between the floor box and the cabinet/bridge. The modules in the floor box should be placed 45° upwards to facilitate the owner's management of the fiber jumpers after construction.

(3) The layout of high-density modules is reasonable. Consider arranging one module in each space to avoid the difficulty of label management.

(4) Reasonably design the length of the optical cable in the distribution frame to avoid excessive fiber coiling due to excessive length or excessive pulling of the optical fiber due to excessive shortness, thereby avoiding damage to the optical cable.

(5) Pay attention to the pulling of the pre-terminated optical cable. All pulling force should be applied to the protective cover.

(6) Pay attention to the protection of the MTP/MPO connector, which is the most vulnerable part of the pre-terminated high-density optical cable.

5. Data Center Acceptance

5.1 Copper Cable Acceptance

The following parameters should be paid attention to in the acceptance of copper cables in the data center:

◆ Wire Map: Wiring diagram (open circuit/short circuit/wrong pair/separate winding).

◆ Length: length.

◆ Attenuation: attenuation.

◆ NEXT: Near-end crosstalk.

◆ Return Loss: Return loss.

◆ ACR: Attenuation crosstalk ratio.

◆ Propagation Delay: Transmission delay.

◆ Delay Skew: Delay difference.

◆ PS NEXT: Comprehensive near-end crosstalk.

◆ EL FEXT: Equivalent far-end crosstalk.

◆ PS ELFEXT: Comprehensive equivalent far-end crosstalk.

5.2 Fiber acceptance

(1) Tester light source selection. During the acceptance test, the test standard and light source bandwidth wavelength can be selected according to Table 1.

(2) Selection of test method:

Method A: The loss result includes a connection at one end of the link.

Method B: The loss result includes the connections at both ends of the link.

Method C: The loss result does not include the connections at each end of the link, and only measures the fiber loss.

(3) Other test points:

◆ Cleaning of fiber optic connectors is crucial for fiber optic testing and often determines the results. It is recommended to clean fiber optic connectors one by one before self-inspection and acceptance, and use special fiber optic cleaning tools.

◆ The correct test-specific jumper must be selected during the test, and it cannot be mixed with ordinary fiber optic jumpers.

◆ Before testing, the benchmark must be set according to different test methods.