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Scenario

I am working in a company where the building with 3 floors (ground + 2 floors) and the current network is running normal is mixed CAT 5 and 5E, 3Com 4200 series / HP 1910 series manager switches 10/100/1000 Mbps twisted pair with about 160 devices (130 employees workstations and 30 servers, equipment) with available space for another 50 employees workstations, complete 210 max (average of 70 per floor).

Beside this building, wall to wall, a new buildingis being constructed, the same level of height 3 floors and with a maximum capacity of 300 (100 per floor). Unfortunately, the budget is low, I'm alone with only with the help of an intern and electrician for physical installation of conduit passage of cables cables, RJ-45 sockets mounted the walls I will. I do not know CAT6 and fiber and in my region has few suppliers.

Questions:

  1. Do I really need to use CAT6 or fiber, 10 Gbps Switch?
  2. I think about installing a powerful Switch between the two buildings to interconnect them, its correct?
Grant
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rodsup
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    I don't have an answer for you, but as a tip, if your question gets closed because of asking for product recommendations or for other reasons, try asking it on Spiceworks. – sa289 Jul 16 '15 at 01:13
  • I have removed your last question because product recommendations are offtopic here. But the rest of your questions are good. – Grant Jul 17 '15 at 04:41
  • Just a quick comment, if you already know how to crimp or install cat5e then doing cat6 won't be much harder. I found it a little more finicky but once you do a few you get the hang of it quickly. Personally I think fibre is overkill however it does come down to how far away the building are as mentioned below – dakka Jul 17 '15 at 07:07
  • Another quick tip - dont use cat6. Make sure you get cat6a. – Grant Jul 17 '15 at 12:21

2 Answers2

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The big reason for using fibre for your buildings will probably be distance, not speed. If the cable runs will be under 100m, CAT5E will work fine for 1gbit, or CAT6a for 10gbit.

Fibre can go for kilometers, if you are willing to pay the premium. It also has the advantage of being more likely to be upgradable without running new cable, just replacing the optics at both ends.

The other reason for fibre is electrically isolating the two buildings. If the buildings have different ground potentials, you can have issues with ethernet. Lightning can also be a concern running cable outdoors. If the buildings are right beside each other, this probably wont be an issue, but it could be.

For where you need switches, and what speeds they need to be, you need to consider the traffic flow between sections. This depends a lot on what people are doing. If a lot of traffic stays local to a floor/department, keeping them all on the same switches means needing less uplink bandwidth.

When you run the cables, dont just run one, at least for relatively cheap ethernet cable. Between the buildings run at least 4 if possible - so you use trunking to combine them for faster speeds between switches, and so you have spares if one breaks. If possible, run the cables in conduit and add pull string to make it easy to add more/upgrade later.

Grant
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  • Even if you're blowing fiber instead of pulling copper it's better to blow more than you need at first, since blowing more later will definitely cost more. If owning phyiscal connections between the buildings is out of budget, it definitely works to use a VPN over the internet or MPLS to connect them. Seems a little galling when they are right next to each other but is definitely an easier financial hit to take up-front. – Todd Wilcox Jul 16 '15 at 13:10
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If you are adding a significant amount of users so your total devices exceeds 254 devices you will need to make sure you adjust your subnet if you currently have a 24 bit mask.

I agree with fiber suggestions. You can run 3 or 4 cat5e or cat6 cables and bond them together (4 cables would give you 4gb but would take up 4 ports on each building). Even 2 would probably work depending on your user activity.

Another alternative is wireless point to point links which you can get very high speeds. Installation may be difficult depending on roof access / mounting.

Vpn would work well but bandwidth will be inconsistent and a fraction of what you get by running cables or doing wireless point to point.

Did you plan on sharing Internet connections?

Are you using a voip based phone system?

In terms of switches, get one 12 or 16 or 24 which can bond cables. And then make it your core for other switches and servers.

David
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    Where do you get the total devices over 253? Even in an old IPV4 network that's not true. – Jim B Jul 16 '15 at 22:31
  • 254 devices if he has 24 bit mask. If he needs more he can supernet. – David Jul 16 '15 at 23:11
  • Just making sure he considers maxing out his subnet and making the needed changes before adding devices beyond the available ips on his subnet – David Jul 16 '15 at 23:13
  • A. I suggest looking into getting a book on IPv4, and IPv6. As a very old example a /8 formerly the largest block available give you 16777216 addresses per network. Everything new should be dual stacked. – Jim B Jul 17 '15 at 03:42
  • Not sure if you are understanding me. If he has 24 bit mask on his network he has a limit of 254 unless he changes his mask to something less. If he changes it /8 he has the 16m limit. I understand that. If he has /24 and he will have more than 254 devices he has to change his subnet mask throughout his network. That was what i was pointing out to op. He said 160 devices and was going to add room for 200 more. He was considering just connecting via switch. So one big network with 360 devices. It wont work on 24 bit if that is what he has. Not arguing the tech, just making sure op considered – David Jul 17 '15 at 03:59
  • I updated the post to be clearer. Hopefully. – David Jul 17 '15 at 04:03