Color-coding your cables

A few months back, a question went out on the North American Network Operators' Group mailing list: Do data center operators use color-coded cables? If so, what colors represent which functions?

Although many agreed that color coding could help administrators identify a cable, few agreed on what color should represent which function. Generally, it depended on what kind of facility it was. A telecommunications center would have different distinctions than say, a collocation facility.

Here was one simple suggestion:
  • Red cables ' to external connections.
  • Yellow cables ' in the DMZ separating internal from external networks.
  • Blue or green cables ' only for internal networks.

However, this scheme could be easily confused: Red could also represent internal cables, the redness signifying the importance of not attaching them to outside devices, while the blue or green could represent that the data traveling over them would be OK for public consumption.

In the intelligence world, cables are sometimes colored in this simple scheme:
  • Red ' unclassified, or unencrypted information runs over these cables.
  • Black ' classified, or encrypted information travels these cables.

Another poster suggested a way to divvy up the color is by users:
  • White ' desktop computers.
  • Black ' telephones.
  • Purple ' modems, faxes, other office equipment.
  • Yellow ' network infrastructure (inter-device, servers, printers, etc.).
  • Red ' connections to outside telephony.

Yet another e-mail poster had a more data center-centric coloring scheme:
  • Blue ' outward-facing servers.
  • Green ' network management cables such as KVM, power.
  • Black ' internal private networks.
  • Yellow ' inter-rack links.
  • Red ' network uplinks.

One rule of thumb is to not use too many colors, said Rudi Van Drumen, chief technology officer for Netherlands-based integrator Competa IT. Too many colors can get rapidly confusing. Use highly contrasting colors as well, so people don't confuse pink for red, for example. Also, he suggested using duller colors (gray) for more mundane functions, such test networks, and brighter, more dramatic colors (red) for mission-critical uses.

Although the cabling set of standards, ANSI TIA 606a does not specify the color of the cables, it does have standardized specifications for the color of the labels on the cable connectors. Again, these might be more handy for telecommunications facilities rather than data centers:
  • Orange ' ventral office connection.
  • Green ' user side of central office connection.
  • Purple ' connections to a PBX, mainframe computer, LAN, or multiplexer.
  • Red ' connections to key telephone systems.
  • White ' terminations of intrabuilding backbone cable connecting main cross-connect (MC) to intermediate cross-connect (IC).
  • Gray ' termination of intrabuilding backbone cable connecting ICs to horizontal cross-connect (HCs).
  • Brown ' termination of backbone cable between buildings.
  • Blue ' terminations of horizontal cable in telecommunications space.
  • Yellow ' alarms, security, or energy management.

About the Author

Joab Jackson is the senior technology editor for Government Computer News.


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