Abstract:
A demarcation device is disclosed. The demarcation device mounts on top of a cable tray. When mounted on the to of a cable tray the demarcation device is above a length of the cable tray and the bottom edge of the demarcation device is parallel with a top edge of the cable tray and a cable path in the cable tray remains un-obstructed.

Description:
BACKGROUND 
     Data centers are becoming denser. The number of devices in each data center is also increasing. Each device in the data center may be connected to the Internet. The connection is typically through either an optical cable or a wired cable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of an example demarcation device  100  mounted on a cable tray. 
         FIG. 2  is an isometric view of an example frame assembly detached from the base  106 . 
         FIG. 3A  is an isometric view of an example base  106 A. 
         FIG. 3B  is a front view of another example base  106 B. 
         FIG. 4  is a front view of an example demarcation device  100 . 
         FIG. 5A  is a front view of an example demarcation device with a patch panel  518  mounted into the frame  102 . 
         FIG. 5B  is a side view of the example demarcation device from  FIG. 5A . 
         FIG. 6  is a side view of two example demarcation device  600  in use. 
     
    
    
     DETAILED DESCRIPTION 
     As data centers become denser the management of cables becomes more difficult. Each device in the data center is typically coupled to a device on the outside of the data center with a cable. The devices inside the data centers are typically mounted in racks. Racks are frames or enclosures with openings for devices that have a standard size, typically 19 inches wide. The height of the openings for the devices is also standardized as multiples of 1.75 inches (44.45 min) or one rack unit or U. The industry standard rack cabinet is 42 U tall. A cable entering the data center would be routed to one of the racks and each strand or sub-strand in the cable would be connected to a device in the rack. 
     Unfortunately all of the devices that the cable is to be connected to may not be located in the same rack. To complete the connection to the proper rack/device, the strand or sub-strand from the original cable would be coupled to a device in the first rack, typically a patch panel, and a second cable would be used to connect the device in the first rack to the final device in a second rack. This creates a number of challenges. The first challenge is that when a patch panel is used to transfer the connection from the first cable to the second cable, the patch panel takes up space in the rack that could be used for other types of devices, for example a server or a storage device. 
     The second challenge created is the increase in complexity and density of the cabling. For each strand or sub-strand that is routed to a rack that is not its final destination, two extra cables are routed to that rack. The first extra cable is the one coining in from outside the data center. A cable coining in from outside the data center will be called an external cable. The second extra cable is run from the first rack to the final destination at the second rack. A cable running between two devices inside the data center will be called an internal cable. 
     Typically the cables are routed through the data center in cable trays. A cable tray is a long tray with a bottom that supports the cables and two sides that keep the cables within the tray. Some cable trays have a top that encloses the cables in the tray. Cable trays come in a number of different types. Some cable trays have solid bottoms and/or sides. Other cable trays are made from wire and have openings along the bottom and sides. Another type of cable trays are called ladder trays because they have evenly spaced supports extending between two side rails (making them look like ladders). Cable trays come in a variety of different widths and depths. For example 6, 8, 12, 16, 18 and 24 inches wide and 2 or 4 inches deep. 
     Typically the cable trays are run under the floor of a data center, along the ceiling of a data center or in both locations. When the cable trays are run along the ceiling, they can be suspended or hung from the ceiling or attached to the walls. The cable trays typically have some clearance between the top of the cable tray and the bottom of the ceiling. This allows access into the trays to route the cables. The clearance between the top of the cable tray and the bottom of the ceiling varies but can range between 12 inches and 3 to 4 feet, depending on the distance between the data center floor and its ceiling and the size of the racks used. 
     In one example of the invention, the area above the cable trays will be used to terminate the external cables coming into the data center. A network device will be mounted in a demarcation device positioned on top of the cable tray. The incoming external cables will be terminated into the front side of the network device. Internal cables will couple to the back side of the network device and run along the cable tray to their final destination inside the data center. 
       FIG. 1  is an isometric view of an example demarcation device  100  mounted on a cable tray. Demarcation device  100  comprises a frame assembly and a base  106 . The frame assembly comprises a frame  102  and two side supports  104 . The frame  102  is fabricated from metal or plastic and forms a rectangular opening. The width of the opening is the standard rack width. The height of the opening is a multiple of the standard rack height. In this example the height of the opening is 6 U. A series of mounting holes are located along both sides of the frame  102  allowing rack mountable devices to be attached to the frame. 
     In this example the two side supports  104  are separate pieces with one attached to each side of the frame. The side supports may also be fabricated from metal or plastic and may be attached to the frame by ally suitable means, for example rivets, screws, glue or the like. The side supports couple with the base  106  and help support the frame and keep it perpendicular to the cable tray. The base  106  is shown attached to a wire cable tray  108 . In other examples the side supports may not be separate parts but may be integrated as part of the frame. 
     As shown, when the base is attached to the cable tray the frame is positioned on top of the cable tray and is perpendicular to the length of the cable tray. The bottom edge of the flame is parallel with the top edge of the cable tray leaving the tray unobstructed so cables can run underneath the frame. 
     In this example the frame assembly is removably attached to the base  106 . In other examples the frame assembly and base  106  may be integrated into one unit. The bottom edge of the frame is parallel with, and resting on, the top edge of the cable tray when the frame assembly is attached to the base  106 . This allows cables to pass underneath the frame when the cables are installed in the cable tray  108 . 
       FIG. 2  is an isometric view of an example frame assembly detached from the base  106 . The base  106  is shown attached to a wire cable tray  108 . In other examples the base may be attached to a different type of cable tray. The frame assembly is attached to the base using any suitable attachment means, in this example two screws  110  are used, one on each side of the frame assembly. In one example tabs along the bottom edge of the side supports  104  fit into slots formed in base  106 . The tabs help align the frame assembly with the base  106  and prevents the frame assembly from moving relative to the base  106  after assembly. 
       FIG. 3A  is an isometric view of an example base  106 A. In this example, base  106 A is a two piece clam shell type design with an upper brace  312  and a lower locking unit  314 . The upper brace  312  is designed to fit inside the cable tray  108  flush with the bottom floor and sides of the cable tray  108 . The lower locking unit  314  fits against the bottom side of the cable tray and attaches to the upper brace  312  with a thumb screw  316  thereby clamping the wires forming the bottom of the cable tray between the upper brace  312  and the lower locking unit  314 . The base described in this example is designed for a wire cable tray. 
     The base may be different for different types of cable trays.  FIG. 3B  is a front view of another example base  106 B. Base  106 B can be used with as solid cable tray, a ladder cable tray, a wire cable tray and the like. Base  106 B comprises a top brace  312 B and two clamps  314 B. The top brace rests on top of the cable tray  108 B. The two clamps  314 B have threaded ends that fit through openings on each side of the top brace  312 B. A wing nut  318  mates with the threaded end to pull the clamp upward. The lower ends of the clamps  314 B are bent to capture the bottom edge of the cable tray as the wing nuts  318  are turned, thereby clamping the top brace to the cable tray  108 B. In other example the base may attach to the sides of a cable tray. Some cable trays have top covers. In some examples the base may attach to the cable tray using the attachment points for the top cover. 
       FIG. 4  is a front view of an example demarcation device  100 . The mounting holes running down both sides of the frame  102  are spaced apart with the Electronic Industries Alliance (EIA) Standard distance for racks, resulting in a total width of 22 inches. In this example, the base  106  is designed for a standard 16 inch wide by 2 inch deep wire cable tray  108 . The frame is designed with a 6 U height, giving the demarcation device  100  a total height of 14.6 inches. 
     In some examples the network device mounted into the demarcation device is a patch panel. The patch panel may be for optical connections, wired connections, or a combination of optical and wired connections.  FIG. 5A  is a front view of an example demarcation device with a patch panel  518  mounted into the frame  102 . Patch panel  518  has two sets of Multiple-Fiber Push-On/Pull-off (MTP/MPO) pass flint connectors  520  and one set of Cat6 connectors  522 .  FIG. 5B  is a side view of the example demarcation device from  FIG. 5A . Patch panel  518  has a hanger  524  to support the incoming cables and a strain relief saddle  526  mounted to the front side. The patch panel shown includes a strain relief. Other patch panels may not include a strain relief. In other examples the network device may not be separate from the frame in the demarcation device, but may be integrated with the frame and mount directly to the base. 
       FIG. 6  is a side view of two example demarcation device  600  in use. The two demarcation devices  600  are mounted on top of a cable tray  608  separated by distance d. The left most demarcation device  600  will be referred to as the first demarcation device  600  and the right most demarcation device  600  will be referred to as the second demarcation device  600 . The distance d between the two demarcation devices  600  depends on the size of the devices mounted into the two demarcation devices  600 . A cable or wire entering the data center will be known as an external cable. A cable or wire connecting one device inside the data center to another device inside the data center will be known as an internal cable. A number of external cables ( 640 ,  611  and  650 ) enter the data center from the left edge of the figure and are located in the cable tray  608 . 
     One external cable  640  is terminated into the from (left) side of a device mounted in the first demarcation device  600 . A first internal cable  642  is connected to the back (right) side of the device mounted in the first demarcation device  600 , and runs along the cable tray underneath the second demarcation device  600  to its final destination inside the data center. A second external cable  644  runs underneath the first demarcation device  600  and is connected to the from (left) side of the device mounted in the second demarcation device  600 . A second internal cable  648  is connected to the back (right) side of the device mounted in the second demarcation device  600 , and runs along the cable tray to its final destination inside the data center. One external cable  650  runs underneath both demarcation devices  600  and is not terminated until it reaches a rack.