DataCenter color-coding cabling schema

Owen DeLong owen at
Mon Mar 14 00:10:26 UTC 2016

I don’t know of any universal standards, but I’ve used the following in several
installatins I was responsible for to good avail:

Twisted Pair:

RED:	Untrusted Network (Internet or possibly DMZ)
YELLOW:	Optional for DMZ networks though I preferred to avoid documented in [1] below
BLUE:	Trusted Network (back-end, internal, etc.)
GREEN:	RS-232 straight-thru
PURPLE:	RS-232 X-Over (effectively Null Modem) 12345678 <-> 87654321 pin map.
ORANGE:	Ethernet X-Over (Best avoided documented in [2] below)
GREY:	Special purpose cabling not in one of the above categories

Orange — Multimode Fiber
Yellow — Singlemode Fiber

The absolute most useful thing you can do if you can impose the discipline to update
the cable map rigorously and/or allocate manpower for periodic audits is to apply a
unique serial number to each cable. I preferred to document not only the cable ID,
but also the length. For the installations where I have worked, 5 digits was sufficient
unique ID, so I used formats like IIIII-L[.L] where IIIII was a unique ID and L.L was
the length of the cable in feet. (e.g. 00123-6.5 is cable number 123 which is 6.5 feet
in length).

The labels are (ideally) the self-laminating wrap-around types. I prefer the Brady
labeling system which will automatically print 2-4 (depending on font size) instances
of the label text on the self-laminating label such that it can be read from virtually
any side of the cable without requiring you to rotate the label into view in most cases.

The Brady labeling system is a bit overpriced compared to the Brother P-Touch, but the
expanded capabilities and the quality of the label adhesives and such is, IMHO, sufficiently
superior to justify the cost.

Whatever you do, please do not use Flag labels on cables… I HATE THEM. They are a constant
source of entanglement and snags. They often get knocked off as a result or mangled beyond
recognition, rendering them useless.

Similarly, I’ve found that circuit-ID and end-point labels on cables are often ill-maintained,
so if you do use them, please make sure you remove them when the cable is moved/removed.

The length is very useful because it gives you a radius within which the other end of
the cable must be located and you can usually expect it to be reasonably close to the
outer edge of that radius.

More than a few times I’ve prevented a serious outage by giving the port number to the remote
hands guy and then insisting that he read me the cable ID. “No, try the other port
FE-0/2/4… You’re off by one. It’s above/left/right/below you.”

[1] I prefer to avoid Yellow cables because some people have trouble understanding
that Yellow Fiber and Yellow UTP might have different meanings. I also feel that the
distinction between UNTRUSTED and DMZ networks is usually not all that important in
most cabling situations. YMMV.

[2] In this era of Auto-MDI/MDI-X ports and the like, it’s very rare to encounter a
situation that truly requires a crossover cable with no viable alternative. If such
is needed, I prefer to document it on the cable tags rather than using a special color
code. Again, you have the risk of people not understanding that orange Fiber might not
mean what Orange copper means. YMMV

Yes, I know you can now get virtually any type of fiber in virtually any color, but
the simple fact of the matter remains that when you send skippy out to buy emergency
jumpers or such, you’re most likely going to either get orange multimode or yellow
singlemode and that’s just the way it is.


> On Mar 12, 2016, at 11:11 , Yardiel Fuentes <yardiel at> wrote:
> Hello Nanog-ers,
> Have any of you had the option or; conversely, do you know of “best
> practices" or “common standards”,  to color code physical cabling for your
> connections in DataCenters for Base-T and FX connections? If so, Could you
> share  any ttype of color-coding schema you are aware of ?…. Yes, this is
> actually considering paying for customized color-coded cabling in a Data
> Center...
> Mr. Google did not really provide me with relevant answers on the above…
> beyond the typical (Orange is for MMF, yellow for SMF, etc)…
> Any reasons for or against it welcome too...
> -- 
> Yardiel Fuentes

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