The TIA-942 Telecommunications Infrastructure Standard for Data Centers has laid down the norms for cabling infrastructure in the Data Center. It defines the overall functional architecture of the data center and proposes demarcation of the functional areas while clearly outlining the guidelines for the placement of cabling, equipment and necessary components. Thus, if you follow the TIA-942 guidelines, you can achieve a well-coordinated and cleanly designed cabling infrastructure for the data center.
TIA proposes the division of a data center into following areas:
- Entrance Room: This is the area in data center where demarcation points, the location for access provider equipment and connecting interfaces with the end users are installed.
- Main Distribution Area (MDA): The MDA is the storage point for the main cross-connect. The switches and core routers constituting LAN are also located here.
- Equipment Distribution Area (EDA): The EDA can be identified by cabinets and racks that securely store end equipment (servers). It is also the place where patch panels for the horizontal cabling coming from the Horizontal Distribution Area are stored.
- Horizontal Distribution Area (HDA): The HDA features cross-connects and active equipment (LAN, SAN, KVM switches) that link to EDA(s).
- Zone Distribution Area (ZDA): This area may be present optionally and acts as a consolidation point that runs between the EDAs and HDA.
- Backbone Cabling and Horizontal Cabling: Backbone Cabling links the entrance room, MDA and HDA. Horizontal Cabling links HDA to EDA, including the ZDA.
Once the layout of the data center is fit in mind in the crystal clear section, cabling is nothing more than filling the color in an empty canvas. To make the cabling faster and easier as well as function-centric, it is important to take following tips into consideration:
- Before starting the actual cabling program, understand the network topology to outline the location of the equipment required to be connected. Then, count the number of ports deployed in EDA. The more the ports, more will be the cabling requirements.
- Find out the distance restrictions that govern the reach from MDA to EDA. If the data center is large, experts may need to deploy more of HDAs to reach the targeted EDAs.
- Determine the cabling capacity of pathways leading to the functional area. It would be easy to set connections between HAD and EDA if the cabling capacity of pathways is appreciable.
- Ensure a lot of physical space for patch panels: Physical space helps locate the pathways and reach the patch panels easily if the latter are located close to the switches.
- Determine the level of security considered must for servers and core switches: of various topologies, the centralized switching topology in HDA offers maximum protection to core switches and servers located in the MDA and EDAs respectively. This topology ensures that these crucial components are not accessible to one and all.
- Keep in mind the future changes and updations: Adopt topology that makes the data center future-ready. Being future-ready in terms of cabling means there should be ample scope for updations and alterations that data center needs to go through with the passage of time. Thus, a distributed topology is avoided in data centers that need making changes in its infrastructure often.
Choosing topology that suits the cabling needs perfectly
There are a number of topology options available for cabling the data centers. These have advantages and disadvantages of their own. All data centers have different design needs; thus, topology is also chosen according to the design.
Topology no 1: Partially Centralized with interconnects
In this topology, the MDA is connected to multiple HDAs having switches; the HDAs are housed in EDA so that networking equipment is closer to it. This topology is achieved by using two-connector channels where horizontal cabling connects the EDA patch panels to those present in HDA. It accepts the new connections easily as EDA patch panel port acts as open end allowing connections with newer switch ports. This is ideal for copper cabling minimization and also does not require numerous patch panels and terminations.
Topology no 2: Centralized cross-connect
This topology chooses 3-connector channels where EDA and HDA patch panels are connected with each other through Horizontal Cabling. Switches in the HDA are connected through cables that terminate in patch panels that actually serve the purpose of the switch panel. The Background Cabling is used to connect MDA with switches in the HDA area. This is quite a flexible topology allowing the alterations to be made in future with added ease.
Topology no 3: Distributed inter-connects
This is very less complex and cost-effective cabling method that requires minimal pathway space. The cable is made to run from MDA to switches in each cabinet of EDA directly; the HDA is eliminated from the scene completely. This cabling method is best applicable in those data centers in which its specific areas are to be controlled individually.
Important rules to follow in cabling data center infrastructures
- Follow specific order while inserting cables. When the pathway starting from under-floor to rack is followed, the upper patch panels should be routed first. Such cables should be placed at the bottom of the channel first and then a connection is to be established. Then, the layers of bundles are orderly placed on each other connected via patch panels that run from upper to lower part of the rack. The opposite cabling route is adopted in case of overhead cable pathways.
- Patch panels should be managed on both sides of the rack; while populating patch cords, start from the outer ports and move to the middle.
- A bundle comprising of 12 cables is optimum vertical manager fill ratio.
- All cable slacks should be tightened; these should not be hanging
Easy management, better reach and flexible infrastructure are considered the best. Adopt the basic guidelines of cabling and make your data center ready to take on the demands of the future.
