Network Engineering Stack Exchange is a question and answer site for network engineers. It only takes a minute to sign up.
Sign up to join this community
I am in the process of designing the network for a new office space. To give a little bit of background...
There will only be one network closet to start with potential for an IDF in the future. This closet will have approximately 600 termination points. My question comes down to design. Is this too much for one rack? Should I split this into two racks? My only thought with why this should happen is strictly ease of cable management.
I would consider this too much for one rack. You always want to leave yourself at least some space for the future. I have seldom been in situations where less space is used in a rack over time, rather quite often the opposite (you end up needing more).
Figure it this way:
For 600 terminations, you will need about 39U worth of switches and patch panels, which doesn't leave much room, especially for things like UPSes or any other equipment.
If you decide you want any horizontal cable management, there isn't room unless integrated into the patch panels and then depending on brand/model, these may be 3U.
If you go with a chassis based switch solution (now or the future), this also wouldn't work as usually these are not as space efficient (while line cards take up only 1U, their power supplies will take up additional space).
If you need to add more cabling in the future, again you wouldn't have space.
Go for the second rack and give yourself some space.
Edit: Adding this to comment on some of the other answers. I left the actual rack layouts out of my answer originally as they are an issue for much discussion as there is no "correct" way to do it. While several good ideas are proposed, a rack design/layout has to address the concerns of your environment and what will provide your organization a reliable and manageable solution.
While there are some things that should be done for any proper installation (racks should be properly grounded, if you use two post racks a ladder rack or other means of securing/stabilizing the top should be installed, etc), many of them come down to personal preference.
For instance, some cabling companies will tell you that you should not put patch panels on the lower 1/3-1/2 of the rack, as it is harder to terminate and prone to more errors. Some will say you shouldn't do any sort of patch panel/switch/patch panel layout as getting access to the back of the patch panels (for additional cabling or repairs) can be restricted.
In earthquake prone areas, some people will tell you that you should mount your equipment in the bottom half of the rack (with heaviest items - UPSes - at the bottom) as this provides a more stable rack. The more weight at the top of the rack, the more the rack has a tendency to sway.
Ultimately, you should put thought into any rack design. Think through the tasks that you will be doing most often, the tasks that are prone to mistakes/errors or can affect other connections, the amount of space you have, your budget and any other considerations the job/site may have.
600 ports would be 25U of 24port panels, just for the RJ45s! Once switches, cable management, and power are added in, that's going to be a very full rack. And it's going to have poor air flow.
It can be done in one rack frame, but you lose some on cable management and future expandability. As this sounds like an "infrastructure wiring" situation, once those patches are terminated, you should never try to move them -- even with slack planned-in, there's a mess of 600 cables in the back of that rack.
I would recommend two racks, minimum. All the termination on one rack, with horizontal "feed-thru" cable managers -- the ones with fingers or a tray out the back to limit how much tangling can occur. And an equipment rack next to it for the switches, power, ups, etc. In this configuration, the cabling is left to be nearly static, while the switch and power infrastructure parts can be changed as necessary as needs and technologies change. (eg. you may only need 120 ports lit at the moment that could be done with 3-4 48port 1U individual or stacked switches, and then move to a larger chassis switch later.)
I usually trade off space for neatness.
My typical layout is:
1' patch cables from top patch panel to the top row of ports on the switch. 1' cables from the bottom patch panel to the bottom row of ports on the switch. These all go under the covers from the cable organizers hiding all cabling.
Repeat from top to bottom in the rack, 5 sets will fit in a 42U with the bottom 6U used for:
Then power supply 1 from the switches go into PDU 1. And power supply 2 from switches goes into PDU 2.
Very neat but uses more space than a lot of people would prefer. Easy to keep track of patch panel ports connecting to switch ports (top row is odd, bottom is even... depending on switch model). Limits you to 240 ports in a 42U rack.
600 Ports per rack would be possible provided you choose the right racks, cable management accessories and patching style.
I'd recommend a 2 Post rack with a pair of high density cable managers. I've personally used Panduit's WMPVHC45E cable managers for similar densities. Now If you use angled patch panels to terminate your copper cables, you can eliminate most of the horizontal cable mangers and save valuable rack space.
Patching can be done such that they are sequential within the left/right halves of the rack. For example for the left side,
And so on for every panel.
This way you'll keep your patch cables short, and within one side of the rack while still being manageable.
However remember such high densities aren't suitable for environments where patch cords are often removed and/or re-patched to a different port.
And remember you'll anyway have to plan for additional space, power and cooling in the network closet if you anticipate expansion in this closet as they aren't easy to add later on.
Without physical limitation, I would say 3 racks are ideal, but 2 racks are a minimum. The middle rack is for patch panels of all cable terminations. You don't want any equipment there. The other racks for equipment. 600 terminations with cable management would take up nearly a 42U rack.
With redundant equipment, I prefer to rack like devices in opposite racks. This avoids the issue of a single power pole affecting all of your redundancy -- imagine worse case even with dual power supplies going to different PDUs in the same rack with your amp draw on a single PDU > half of it's capacity. Now imagine one of the PDU fails, so all the equipment then pulls double the amps from the remaining PDUs, and since your over budget on your draw, you just tripped the breaker on your redundant PDU and all equipment in that rack goes offline. Having like equipment -- redundant routers, firewalls, agg switches, access switches, wireless LAN controllers, etc -- in different racks would mean a single rack can take it all out. You also avoid someone falling off a ladder or tripping and ripping cables out of your equipment and having a bigger impact than you would like.
I would consider spliting them into two racks. That way it will allow for future expansion of the network. At the moment you may feel that you won't need to expand any further.
Trust me, it makes life a lot easier if you allow some room for future expansion now, rather than try to expand further down the line.
