We’ve all heard the expression “the network is the computer.” Many people make a handsome living making sure data center switches and routers from vendors like Cisco, Juniper or others hum along nicely.
And while we’re hearing about the impacts of wireless, wireless data centers seem to be a long way off…leaving data centers filled with miles of wire…cables…and patch cables.
Non-technical managers may simply say “cable is cable” and not fully appreciate the value of a cable plant thoughtfully designed and implemented.
Every cable type (wired or fiber) has designed speed and maximum length characteristics. It is amazing to me the number of times in a large data center a “flaky cable” ends up being of a cable length over the designed maximum length. In my mind, it should be called a “flaky installation.”
A well-executed cabling job can qualify as a work of art.
We use some basic guidelines around patching we think make sense. These are often applicable in high end data centers, with suitable modifications for smaller shops.
A word on “making cables.” Small shops seem to love to “make cables.” Small shops often don’t really have the expertise to field make and test a cable. When the costs of making the cable are included (it is not “free”), the savings through reduced troubleshooting become clear.
There are numerous documents available qualifying as “prior art” on cable plants. Here’s some high level guidelines we used on a recent immplementation:
General
- Plastic zip ties are not permitted for cable management for either copper or fiber patch cords. Hook and loop fasteners (aka, Velcro®) shall be used to dress bundles of cables and to provide strain relief.
- All patch cords must be sized appropriately for the application, with only a small service loop at each end to facilitate tracing. Large loops of excess cable are not permitted.
- All cables must be neatly routed and dressed.
- Only patch cords from reputable, nationally known, industry recognized firms such as Belden, Siemon, Ortronics, TYCO/AMP, Corning, etc. are permitted. “No brand” generic cords are not permitted.
Copper Network Patch Cords
- All copper patch cords must be “factory” manufactured, terminated, and tested in an appropriate facility. Field-terminated cords are not permitted.
- All copper patch cords shall be ANSI/EIA Category 6A (Cat 6A) tested and certified.
- All Cat 6A patch cords shall be F/UTP or STP construction.
Fiber Patch Cords
- All fiber patch cords must be “factory” manufactured, terminated, and tested in an appropriate facility.
- Field-terminated cords are not permitted.
- Multimode fiber patch cords shall be OM3, laser optimized multi-mode fiber (LOMMF), supporting 10Gb Ethernet to 300m
- Single mode fiber patch cords shall be OS1
- Connector types shall be coordinated with the Client appropriate to the application.
Other Patch Cords
- Patch cords for DS1 (T-1) circuits shall be Cat 6A.
- Patch cords for DS0 circuits may be made on site to provide for specific pinnings or connector type. Cords should be tested with a pair tester.
- Patch cords for DS3 circuits may be made on-site with the appropriate co-axial cable and connectors. Cords should be tested for continuity with an ohm meter or co-axial cable tester if available.
Data Center Cable Naming Standards
- Two labels on each wire on each end (4 labels per wire)
- First label is RX-X where X-X is the rack number and the run number
- The second label is P.X.X where X.X is the port of the switch it is plugged into
Data Center Cable Color Standards
- End User Connection - Blue
- LAN Server Connections - Orange
- Management (iLO and KVM) - Green
- DMZ – Pink
- Phones - White
- Internal Uplinks: Yellow
- External uplink: Grey or Black
What standards/practices do you find valuable?