Co-location Facility (CS Building)

This page describes the CS co-location facility in Room 002 of the Computer Science Building.


The room is configured with 10 racks. Eight racks are available for use by research groups and two are used by CS Staff for department infrastructure. Beginning in FY13, rack space is allocated by the "quarter-rack".

Each quarter-rack has the following standard features:

  • 10 rack-units ("U") of available space.
  • 10 power outlets (120V) using up to 2500 watts of measured power.  (Note that a server with a 250 watt power supply will rarely draw that much power.)
  • 5 ports on the top-of-rack patch-panel that terminate in the communication rack. These ports can be patched to 1Gb/sec network ports that are either "inside" or "outside" the CS firewall. The patch-panel ports also allow direct connections to other racks or other network boxes in the CS building.

Full racks have 4x the resources (i.e., 40U, 40 outlets, 20 ports on the patch-panel).

Power / Cooling

Power available to equipment in the racks is 120 volt AC single phase.  (208V is possible; contact CS Staff if you have a requirement.)  Racks have two available power feeds: commercial (unprotected) power and UPS-protected power.  We expect that all equipment in the racks will use UPS-protected power; however, upon request. unprotected power can be provided.

The bulk of the cooling in the room is provided by the main air handler on the north wall.  In addition, there is a unit in the ceiling as well as smaller units along the east wall.

The room has the capacity to power and cool an average of approximately 11kVA to each rack. This roughly corresponds to an average of 250 Watts per 1U over the 40U available in each rack.

Under normal conditions, power and cooling (i.e., chilled water) for 002 is provided by the Princeton Energy Plant.

In the event of a power failure, a 120kVA UPS in the CS mechanical room will provide battery backup power to the racks.  The available battery time will vary depending on the power load. Note that the UPS is sized to provide power for the racks in the event of short interruptions in power.  Nearly all of the unscheduled power interruptions in the past several years have been under 2 minutes.  In addition, the power for the main air handler will be provided by a backup generator.

In the event of a chilled water shutdown from main campus, a backup chiller in the mechanical room will come online and provide cooling to the main air handler in room 002. NOTE: the backup chiller is not powered by backup power.

In the event of a simultaneous power and chilled water failure, the room is expected to stay safely cool enough for equipment for as long as the UPS can supply battery power.

Research projects that need either additional power outlets or more power than can be supplied by one power distribution unit (PDU), must contact CS Staff. In all cases, we will specify and install the PDU. If we do not have any spare PDUs in stock, the research project will need to purchase the CS Staff-specified PDU.

Fire Suppression

Room 002 uses a pre-action fire suppression system (single interlock).

Network Connections / Top-of-Rack (ToR) Switches

As with all other locations on the CS network, equipment and their network configuration are subject to CS Staff approval.

Each rack has a 24-port patch-panel that terminates in the communication rack. This provides the uplink and allows racks to be patched together. (Note: CS Staff reserves 4 ports for links to PDUs leaving 20 ports available to the researchers.)

The communication rack (where each rack's patch-panel terminates) includes a single 10Gb/sec uplink to the CS core switch.  Within the comm rack, there are switches that provide 1Gb/sec ports that are either inside or outside the CS firewall.  These ports are patched to the racks as needed.

[Note: the remainder of this section is identical for both of the CS co-location facilities.]

Note that all ports exposed to users are "untagged" and are configured to operate on a single VLAN (per port).

The expectation is that the equipment in each rack may require some number of network connections that are "inside" the firewall and some number of network connections that are "outside" the firewall. These connections can be made with the provided patch-panel. If a researcher needs more connections than available in the patch-panel, they will need to use a switch. Note that the CS networking infrastructure maintains physical separation between "inside" and "outside" the firewall. In some cases, you may need more than one switch. Contact CS Staff for details.

If you supply and manage your own switch, its uplink will be to a single VLAN.

If you have more complex networking needs and/or want CS Staff to manage your switch as part of the departmental infrastructure, you will need to purchase the departmental standard switch, an HP E6600-48G-4XG (no longer available, see CS Staff for alternatives), along with a 5-year software support contract.  IMPORTANT: There are a few remaining Foundry switches in these racks that CS Staff manages on behalf of the research project. CS Staff will continue to manage these until they fail at which time the research project must purchase a replacement switch as specified above.

If two researchers are assigned to the same rack and they need more ports than provided by the patch-panel, they may jointly purchase a switch and share it.


Basement level of the CS Building.

Physical Access

The policy is that anyone who owns or maintains a machine in CS 002 may have access to the room. Access is via a hotel-style lock using one's TigerCard. To gain access, the owner of the machine or rack should send an email request to CS Staff and include the NetID as well as the name and PUID number (as printed on the TigerCard) of the person who should have access. All researchers with access must subscribe to the cs-002 mailing list.

Each rack is equipped with a combination lock. Upon request, CS Staff can set this combination to a specific value to further limit access to an individual rack.

Current list of CS people with access is here (login required).


These rules are designed to keep the room clean, safe, and effective for research.

  • No food or drink in the room -- critters have been seen in other areas of the CS building. We don't want them in the room and we don't want exterminators putting traps and/or chemical bait in the room.
  • Do not turn off the A/C unit -- the room now has enough active equipment that the A/C must remain on at all times. Hearing protectors are available on the window ledge; please use them when you expect to be working in the room for extended periods of time.
  • No storage -- the room is not to be used as a storage facility. In particular, cardboard boxes should not be brought in the room. Cardboard sheds dust that can clog air filters and equipment.  Unpack equipment outside the room.  If you need a cart, contact CS Staff.
  • Do not block the electrical panels -- NEC requires 36 inches of clearance in front of the panels. For reference, the floor tiles are 24 inches square.
  • All equipment must be registered -- Any equipment that has an Ethernet interface must be registered in the CS inventory system. This applies even in the case that the equipment will be behind a private switch.
  • Equipment must be rack-mounted -- Check with CS Staff if you are considering bringing non-rack-mount equipment into the facility.  For example, a desktop machine would not be allowed but an external USB drive connected to a server would be OK.
  • Please keep racks neat and cables dressed -- CS Staff can assist upon request.  We have short power cords as well as network patch-cables of varying lengths for use in 002 racks.  By keeping cables neatly dressed in cable management channels, there is better airflow and cooling for your equipment.
  • Do not prop open the hall door -- This is both a security issue as well as a cooling issue.


Beginning FY2015, researchers are not charged for basic space, power, cooling, or networking (i.e., those outlined in the Specifications section above).  If a researcher needs resources beyond those outlined above, these costs must be picked up by the research project.  For example, needing 10 Gb/sec uplinks to a given rack, additional/specialized ports requiring a CS Staff managed switch, or specialized power.

In the unforeseen event that there are significant charges that are appropriately passed along to all the occupants of the room, each quarter-rack of assigned space will be charged 1/40 of the total cost and the Department will pick up the remainder.  (With 10 racks in the room, there are 40 quarter-rack "slots.")

Getting Rack Space

Rack space is assigned to faculty upon request and is subject to availability. If you plan on using rack space in the room, please contact CS Staff well in advance. (Just because there is empty space in the room, it doesn't mean that it is available.)

Rack slots are numbered from the bottom of the rack. Quarter-racks are assigned slots 1-10, 11-20, 21-30, or 31-40. For mechanical stability, CS Staff will assign quarter racks beginning from the bottom and researchers should install heavier equipment in the lower numbered slots in their section.

Current rack assignments are here (login required).

Vacating Rack Space

When vacating rack space, all equipment provided by CS Staff must be returned. This typically includes power strips, patch panels, cable management, power cords, and network cables. Rack space is not considered vacated until the assigned slots are empty, assigned patch-panel ports are unconnected, and assigned power outlets are unconnected. Potential cost sharing will continue until all assigned resources are freed.

Pooling Resources

If two or more researchers are assigned to a particular rack, they may wish to pool their resources. For example, one researcher may only need one (of their 5) ports on the patch-panel and let another researcher use the extra. Similarly, two or more researchers may jointly purchase a shared switch for their joint use.

Keep in mind that if one researcher wishes to vacate their space, they are subject to potential charges until all their assigned resources are released.

"Subletting" Space

There are also occasions when a researcher in the department needs just a little bit of rack space and someone already assigned space has a little extra space available. It is OK for one researcher to let another researcher use some of their assigned space.

Keep in mind that if the researcher assigned to the space wishes to vacate, they are subject to potential shared charges until all their assigned resources are released.