Plexiglas inserts in front doors were once characteristic to most cabinet designs. Unfortunately, for most cabinet manufacturers, this configuration became common practice. However, increasing heat dissipation needs of modern servers has resulted in cabinet owners having to replace their cabinets, or purchase replacement panel inserts with 80% perforation.
Modern cabinets can contain as many as 288 blade servers, and up to 42 small-form-factor servers. Such deployments require special attention to power distribution, network connectivity, and heat dissipation needs of the server cabinet.
Modern server cabinets must be configured to support a minimum of 24 servers, each with: - dual power connections - dual LAN connections - dual SAN connections - a KVM connection plus an additional connection for RS-232, T-1, modem, or network connection for remote monitoring/management.
Using an extension at the rear of the cabinet enables vertical mount of up to 6 patch panels, which provides extra space for high-density distribution of network cabling. This revolutionary design offers increased connectivity per cabinet, with maximum flexibility, while retaining all attributes of a structured cabling infrastructure.
Pictured here is a 42U server cabinet consisting of 96 UTP connections, with provisions for up to 48 fiber connections. 96 copper UTP connections are subdivided into 4 color-coded networks: - 2 for redundant LAN connections, - a KVM connection, - and one additional segment for RS-232, T-1, and modem line connectivity. Additional provisions are available for up to 48 fiber connections, subdivided into 2 segments for redundant SAN or NAS connectivity.
Three of these vertically mounted patch panels will net 72 connections per side. Upon closer look, you will notice three alternating colors of RJ-45 connectors distributed across the left side of this 42U server cabinet. Each color represents a separate physical network.
Dual Power Distribution Units in the cabinet's sidewalls offer up to 48 power connections per cabinet. This provides 100% fail over redundancy. And by mounting them in a "Zero Rack U" configuration, full cabinet utilization for equipment is permitted with no wasted space for power strips.
U Designation Strips ensure that all rack-mounted devices are installed according to EIA/TIA rack standards, making rack units easily identifiable, thus eliminating poor space utilization caused by crooked mounting of devices or in a manner that split rack units.
KVM modules use twisted pair cable, instead of bulky, vendor-specific KVM cables thus decreasing cable congestion RJ-45 ports on the KVM switch can be connected through patch panels, enabling remote switch location and more rack space is reserved for tower servers.
Old cabling methods for raised access floors (1 of 6)
For years, property owners and IT managers have permitted the installation of data cabling under access floors to be performed by network administrators or cabling technicians, not knowing that specific guidelines regarding the cabling methods in these areas are stipulated within various fire and building codes, particularly NFPA-70 the National Electrical Code, strict adherence to which is required by law.
Old cabling methods for raised access floors (2 of 6)
Because access floors are used as pathways for cabling, NEC specifies maximum fill percentage not to exceed 40%. Excess cabling also restricts air flow through the plenum floor, thus creating problems dissipating the excessive heat generated by data center equipment.
Old cabling methods for raised access floors (3 of 6)
An example of potential fire hazards that often lurk beneath a raised floor. There is live voltage on this circuit's exposed current-carrying conductors. This was an accident waiting to happen for an unsuspecting technician to possibly come into contact with live voltage while pulling a network cable, or cause the exposed conductors to make contact with a ground source, thus creating an arc, and potentially causing a fire.
Old cabling methods for raised access floors (4 of 6)
As equipment is replaced, often requiring new cabling to be added, old cables are seldom removed and often abandoned. Inevitably, this practice leads to eventually exceeding the maximum allowable fill percentages.
Old cabling methods for raised access floors (5 of 6)
Erratic pathways and installation methods will eventually lead to the virtually impossible task of removing old unused cabling, presenting high risk of accidental impact to network operations and up-time statistics.
Old cabling methods for raised access floors (6 of 6)
Many of the cables installed in this floor are PVC (not plenum rated), which produces extremely toxic smoke during a fire. What's more, using non-locking electrical plugs and cords increases the risk of fire.
New cabling methods for raised access floors (2 of 4)
Where power and data pathways are run parallel to one another, they should occupy alternate rows of the floor grid, with an empty row inserted in between, for maintaining separation between power and data cabling, and also offers the additional benefit of promoting unrestricted airflow of HVAC distribution beneath plenum floors.
New cabling methods for raised access floors (3 of 4)
Each pathway should be at a distinct, predefined elevation, eliminating the need for offsets at intersections. Power pathways should be the bottom elevation, while data pathways should be at higher elevations. Where data and power pathways intersect, they should be at 90? relative angles to one another to minimize noise induction.
New cabling methods for raised access floors (4 of 4)
If the raised floor height is low (less than 12 inches deep), there may not be sufficient space for routing both cabling and power, much less for divided elevations. In this case, installing part or all of the data cabling can be installed overhead, thus significantly reducing the raised floor cabling congestion, thus preventing unbalanced distribution of HVAC system due to airflow restrictions. Since under-floor cabling requires use of plenum-rated, overhead installations of pathways offers
Bill Detwiler is Editor in Chief of TechRepublic and the host of Cracking Open, CNET and TechRepublic's popular online show. Prior to joining TechRepublic in 2000, Bill was an IT manager, database administrator, and desktop support specialist in the ...