Network Racks For Surveillance Guide

By Sean Patton, Published Mar 21, 2018, 03:18pm EDT

In this guide, we look at network rack infrastructure, one of the fundamentals of IP video surveillance. Inside, we cover:

  • What is a rack unit (RU)?
  • Square vs. threaded mounting holes
  • Open frame
  • Closed cabinets
  • Wall mount vs. floor mount
  • Full vs. switch depth racks
  • Rack security
  • Cable trays/ladder rack
  • Rack layout
  • Cable management
  • Ventilation
  • Passive cooling
  • Active cooling
  • Accessories

What Is a Rack Unit?

A rack unit, aka "RU" or simply "U", is the standardized unit of measurement for all networking equipment racks and hardware. It is defined as 1.75 inches/44.5mm tall by 19"/482.6mm wide, officially established as a standard in the early 1920s.

Racks and equipment are commonly specified in RUs. For example, the common standard for a full height rack is 42U or 44U. Switches, recorders, shelves, and other rack mount devices often list rack units on their spec sheets, such as this NVR:

 

Square Vs. Threaded Mounting Holes

Some racks use threaded holes for mounting equipment, while others use square holes which accept a captive nut (called cage nuts). Mounting rails are typically designed for one or the other, but not both of these styles.

Exposed Frame Open Racks

Exposed Frame Open Racks are lighter, cost-effective way of mounting rack hardware, also providing open access to connect wires and allowing free airflow on all sides of the equipment. There are different forms of Exposed Frame racks:

  • **** **** **** ***** ***** are ********* **** *** ******** larger ********* **** ** NVR/VMS *******, ********, *** large ***. **** ******* a ***** ***** ***** to ** ****** **, and * ***** ***** structure ** ** ******** to.
  • *** **** ***** *** be ******** *** **** cable ***** ******, ***** terminations ** *********/******* *********. **** are *** ******** ** hold **** **** ***** devices, **** ** *** servers, *** ******* * much ******* ***** ***** but ***** **** ** be ******** ******** ** the *****.
  • **** ***** ***** *** typically **** *** ***** patch ******, ***** ************. They *** ********* ******* to **-****** ******* **** and **** **** - 20in ****, ** ***** servers, ******** ** *** equipment *** *** *********** for ************ ** **** Mount *****.
  • ******** **** ***** ***** *** ****** traditional ***** ** **** hardware ***** **** **** the **** *****, ******** larger ******** *** ******** small ******* ** ** wall ******* ** * more ******* *****.

Enclosed ******* *****

******** ******* ***** ******* physical ******** ** ******* server *** ****** *****, and ***** *** *********** intake *** ******* *** for *********** **** ********* operation ** ****-******* ********. ** with **** ***** ******, cabinets **** ** ******* different *****:

 

  • **** **** ***** ******** provide **** ** *** same ************* ** ** open * **** ****, but *** ** ****** secured **** ******* ***** and ***** *** *** ability ** ******* *** ventilation *** *** **** in *** *** ** the *******.
  • ****** ****** **** ***** cabinets *** ********* * compact *** ** ******** smaller ******* ********* (*-** port ********, ***** ******, small ***) ** * smaller **** ******* ***** up *** ***** **** estate. **** *** **** be ******, *** ******** have ******* *** ******** ** the ******* ** *** wall ** ***** *** ceiling. ***** ** ** way ** ****** *** rear ** *** ******** or ***** ****** ** a ****** ****** *******.
  • ****** ****** **** ***** cabinets *** ********* ****** than ****** ****** ****** *** offer ****** ** *** back ** *** ********* in *** **** ******* having ** ****** ** from *** *******. **** makes *********** ***** ****** or ******** *** ******** much ******.
  • ******** **** ***** ********, are ** ******** ******* of *** ******** ***** open ****, **** ******** larger ******** *** ******* to ** **** ******* in * **** ******* space (**"-**" ** *******), and ********* ******** ** a ******** *******. **** are ***** *** ***** max ****** ** *******.

Full ***** ** ****** *****

*** ***** ******** ** any **** ****** ** the ***** ** *** enclosure. ***** ************ ************ ***** ********** ***** * **** racks ******* **** **" to **". *** ******* rack ***** *** ******** servers ** **", ***** on *** ****** ** Dell [**** ** ****** available],***, ********.

******* ***** ** ** true ******** *** "****** depth", ***** *** *** common ****** ***** ****** watch *** ***:

  • ******* "****** *****" *****: ******* ******* ********* ****** to **", **** ************* advertise **" **** ***** as "****** *****."
  • **** ***** ******* *******:******* *** ****** ***** wall ***** ***** *** limited. ***** ******** ********* may ****** *** ** wall ***** ******, **** size *** ******* ****** require * ***** ***** rack *** ** ***** depth.

Physical ******** ***********

******* ******** *********** **** changed *** *** ** departments **** ** **** at ******** ********. **** regulations (*****, ***-***) ***'* currently ******* *******-***** ******** control, **** ***** ****** control (**** ******-*** *.* ******** *********):

*.* - ***** ****** to ****** ********** *** cardholder **** ** **** those *********** ***** *** requires **** ******
*.* - ********* ** access ******* ******(*) *** systems ********** **** ********* access ***** ** * user’sneed ** ****, *** is *** ** “**** all” ****** ************ *******.

****** **** *************, *** ******** ******** specific ************ *** ****** to ********.

Cabinet ********

******* ******* ******** ********** varies. **** ** *** technologies ** ***** ***:

  • *********** **** *** *****
  • ********** ****** *******
  • *** ******/**** *********

******* ******** *** ***** ******* with ***** ******** ***** and/or ***** ******* **** simple **** *** **** to ******. ************, **** racks **** **** ********* side ****** ** **** doors **** *** ******* with ******** *****.

********** ****** ******* ******* are ********* *** ******* cabinet *******, **** *********** swing ****** ***** *** cylindrical *********** ******** ***** from***,*******,*******, *** ******. **** of ***** **** ********** Wiegand **** ******* ******** on *** **** ****.

* *** ****** ** a */**" ****** ****** that ** * **** ************ **** to **** *********/**** ************ terminals (****). *******, **** cabinets *** **** **** fastener, ** ****, ** close *** *** ** the ******* (******** ** addition ** * *******). 

Open ***** ********

** ******, **** ***** racks *** **** ****** than ********, ** *******, power, *** ******** *** exposed ******* ** ****** in ** *********. ******* of ****, **** ***** racks *** ********* **** only ** ****** ***** such ** ****** *****.

***** *** **** ** lock **** **** *********** in **** ***** ***** from ****** *********, **** as ******** ****** ***** mount **** *** ***** of ********* (*****). *** determined ********* **** **** other *** ** ********** or ******* *********.

Switch **** ********

** ******** ** **** security, ***** ******* **** ***** ****** or ***** ***** *** switch *****. **** ******* *** * combination ** ** ****** and ***** ***** ********* lock, **** * ******* key.

**** ** *** ************* that ***** ******* ******* are:

Rack ******

***** *** ** *** standards *** ***** **** piece ** ********* ** mounted ** * ****, as **** ************ *** equipment ******** ******, *** there * *** ******* guidelines ** ********:

  • ***** *** ********* *** heaviest ******** ****** ** any **** *** ****** be ******* ** *** bottom ** *** **** for *********.
  • ***** ***** ****** *** ***** ******** cable *********** *** **** often ******* ** *** top ** *** ****, since **** *** ******** much **** ********** **** station/device ******* *** ********.
  • ** * ***/******* *** used, **** ****** ** placed ** ******* ******, generally **-**" ** ** not ** ** *** high/low ** *********** ***.

*** ****** ** *** rack ***** ** **** most, ** ******* **** as ****** *** ***** panel *******, ****** ******** and ****, *** ***** devices ****** ******.

Cable **********

***** ********** ****** *** rack ** ** ******** as *** ***** *** in ******** ** ***** the *******. ** ** where *** **** *******, troubleshooting, *** ********* **** be ****. ******** ******* cable *** ******** *** also * ***** ********* of * ********** ******* with **** *** ****** technique.

***** *** *** ****** approaches ** ******** ******/***** panel ******:

  • ***** ****** *** ******** grouped:** **** ********, ***** panels *** ******* ******** to **** *****, ** our ********, *** ****** patch ****** **** ** connect ***** ****** ** switches. **** ******** ***** it ****** ** *** future ***** ****** ** switches, *** ****** **** be ****** *** *** more ********* ** *****.

  • ***** ****** ******* **** to ********:** **** ********, ***** panels *** ******** *** grouped ********, **** ******* patch ****** **** ** connect *** ***. **** method ******* *** **** for ********** ***** ********, since **** *** *****. However, ** ** **** flexible *** ****** ***** because **** ****** ***** may *** ** ******* adjacent ** ***** **** added ***** *** ******* installation.

Enclosure ***********

******* ********* ******* ****** is **** ********* **** considering **** **** ** enclosure, *** **** *********** control ** *** *******.

  • **** **** ***** ** *** provide *** *** ** containing *** ********* *** exhaust *** **** **** the ****** ****** *** and *********** ******* *** air **** **** *** room, ***** **** ** climate **********.
  • ******** **** ** ***** mount ******* ******* *** be **** **********, **** many ********* ***** **** for **** ** *** top ***/** ****** ***** allow *** ** ** vented **** ****** ****** or **** *****.

Equipment *********** *****

**** ******* ** ****** manufacturer *** **** ********* specifications *** ****** *** exhaust ** ***** *********. They **** ***** *** "front **** ** **** side" ** "**** **** exhaust ** **** **** intake".

** ***** ************, "*****" means *** **** ** the ****** **** **** and ***** **********, ***** "back" ***** *** **** with *** ******* ***** - ******** ***** ****** fans *** **** ********* but *** ** ******* with ***** (** ***** connectors ****) *******.

**** ****** ************* *** rear *******, ** **** they ******* *** *** where *** ***** *** network *********** ***, *** intake ** *** ***** and *****.

Passive **. ****** *******

***** *** *** ***** of ******* **** ** rack ************:

  • ******* ******* ***** ******* on ******* *** **** from *** ******* ** the ******* *** ******** to ***** **** *** to **** **** *** cabinet.
  • ****** ******* ***** ***** exhaust *** ** **** to ****** *** *** air **** *** **** area, ******** *** ****** of **** *** ** happen **** ***********, ******* equipment ******.

******* ******* ** **** common ** ***** **** closets ** ***-**** ****** environments, ********** * *** switches ** ******** ********* which ********* ** *** produce ******* ****. *** conditioning ***** **** *** into *** **** ******* either ********* **** ** building **** *** **** to **** *** ****** room ****. **** ** inefficient, *** *** ******* investment ****** ** **** network ********* **** *** functioning.

*** ****** ** ****** cooling ** *** ***** and **** ***** ***********, a ******* ******** ** modern **** ******* *** isolating *** **** ****** air **** *** *** exhaust ***, ** ******** the ******* ******* ********* ducting/chimneys *** * ****** ceiling *****. **** ******** a ********* ******* **** and * ****** ***** plenum ******. 

*** ***** ******** ** any ******* **** ***** to ** **** ** the *** ***** ** the **** ** *** racks, **** ** **** in **** *** ******* conditions, ***** ** ******* F. ** **** ******** more ***** *** *** exhaust ******, *** ** a *** ** * server ** ****** *****, it **** ***** *** more **** ** ******* the ***, ** **** down *** *********, ****** catastrophic *********** ***** *****.

Other **** *********** 

***** **** ******* ********* such ** ********, *********, servers, *** ***** ******, there *** ******* ****** rack ***********:

*** ********

**** **** ************* **** have ******** ******* ****** the **** **** ** grouping ** *****. ** place ** ******** ********, keyboards *** **** *** control *** ******* ** each ******, * *** (Keyboard/Video/Mouse) ****** ****** *** control ** ******** ******* from * ******* *****. The **** ****** **** is * ***** *** rack **** **** ******* monitor, *** *** **** be * ********** ****** with ******** *******, ***** and ********.

 

**** *******

**** ******* *** ***** used ** **** ********* which ** *** ******** intended ** **** *****, such ** ***** ******/*******, small *********, ** ******* PCs. 

*******

**** ******* *** ******** used ** ***** ******, manuals, *****, ** ***** materials ***** *** ** frequently ******. ******* ***** from **-**, *********, *** up ** ~**" *****.

******

*******, **** ***** ****** may ** **** ** illuminate ******* ***** ** the *****/**** ** *****. This *** ** ********** useful *** ********* *** rear ** ******** ********, as ******* ***** ** the **** *** *** reach ***** *****.

Comments (14)

Thank you for making this.  Another definitive example of the little tools I need and look for as an active participant in this industry.  Security folks are equivalent to the veterinarians of all the trades; a horse, a pig, a chicken - all in the same day!

Thanks for helping us stay skilled when putting all the pieces together.

 

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No mention of a rack KVM switch.

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Good point, I added a section in accessories for KVMs.

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I love the active cooling diagram.

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 I'd be interested in any info on rack use in earthquake prone areas.

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Tony, several vendors make seismic proof racks.

Typically, these are anchored to the floor / tiles.

 

Tom

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I know of and use racks rated for Zone 4, but I don't really know what that means. As long as I have been doing this, I have never seen an engineering-level explanation of how they get rated, or if the equipment weight distribution matters.

In my group we assume the rack will wobble, but we've not been very good about specifying cable slack to allow for that.  Didn't think it mattered all that much when everything was copper, but I can see potential issues using fiber.

Another group I work with braces the top of the rack to the wall or ceiling with all-thread to eliminate wobble.  Though we have these two different standards I have no way of telling which is better.

Of course a four-post rack would undoubtedly be stronger, but they end up taking more space too, so there's a significant real-estate cost to using them, on top of the purchase price difference.

Someone somewhere has probably done research into this, but I've never come across it.

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The active cooling diagram seem the rack back/front direction should be opposite. The server chassis front is sucking air and air come out from the back. 

Agree: 1
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That is correct, the graphic has been updated to reflect this.

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Interesting. I believe grounding the rack is required to safeguard the equipment's.

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Nice article.

"zone 4" appears to mean "near an active earthquake fault", as in this.  So I guess you always see racks bolted to the floor or structure.

You don't mention bend radius rules, or fiber optic cable, or wiring run rules for wiegand/rs485 cable.

(do not mash the cables.  there's actually a "bend radius" rule, probably in a BICSI spec.  And while cat 5 for data wants to be neat and parallel, wiegand and rs485 do better (some say) by being run back and forth diagonally in cable trays.)

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I likely won't ever be involved in any type of enterprise level work, but this is still extremely nice-to-know information.  Thanks!

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I think it's important to note as well the door.  It can be either glass or metal.  Metal doors are usually meshed thus offering better ventilation.  But glass doors are more convenient when troubleshooting, all device statuses/cabling is easily visible without opening the door.

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We have ran into Rack Units advertised as "server sized", where the depth came in an inch or two short of the DVR, Switch, and keyboard trays. It is always frustrating having to renovate and update the structure of the rack units in last-minute attempts to make the enclosures work.

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