In our office, we have our router that is connected to the internet.
From there, we would like to lay an ethernet cable to 3 other rooms with about 30 computers.
We were considering the following setup:

Router --> Ethernet cable (10 meters) --> Switch in Room 1 -->
Ethernet cable (5 meters) --> Switch in Room 2 -->
Ethernet cable (30 meters) --> Switch in Room 3

Now my question: Will we have any performance issues due to the fact that all users will share this one single line?
What kind of ethernet cable would you recommend? Cat7?
Any other problems we might run into?

Internet connection is 50 Mbit down, 10 Mbit up.
The router is an AVM FRITZ!Box 3490 which supports QoS: http://www.amazon.de/dp/B00N80INBM
Switches and ethernet cables will be bought soon.
The computers will use the following services:
- Regular "surfing"
- SSH / FTP to external servers
- Accessing internal file server

  • Are you asking about efficiency of network topology for your purpose? If so, you will have no problems. Only problems that might arise come from bandwidth given by ISP and load generated by 30 users/computers at the same time. If you have good connection and QOS implemented - there will be no issues what so ever. Edit: I hope your router is not a home router like linksys etc. Those could show poor performance when so much traffic will come through them.
    – mnmnc
    Nov 30, 2015 at 11:35
  • 2
    1) It depends. 2) It depends. 3) It depends. -- You're not even telling us what kind of internet connection you have. Additionally, You're not telling us what kind of computers will be connected to which switch. Will these computers provide services for your LAN? For a WAN? For the web? What kind of work will be performed at the workstations? Call center with VoIP? Website data upload?
    – Run CMD
    Nov 30, 2015 at 11:38
  • 1
    "Is my pipe big enough?" Are you running "ethernet", "fast ethernet", "gigabit ethernet" (Which should be the minimum here) or 10gbe over copper? (Cat 7 is for the last. Cat 6 should handle gigabit fine). Can your router handle these connections? How much traffic does each user user?
    – Journeyman Geek
    Nov 30, 2015 at 11:55
  • 1
    What kind of switches? What kind of traffic? What kind of performance are you expecting? Nov 30, 2015 at 11:59
  • 1
    It's all going to come down to access to the file server. If your Internet connection is only 50Mbps in its fastest direction, even a single connection using ancient "fast Ethernet" is more than fast enough. Nov 30, 2015 at 12:21

2 Answers 2


I wouldn't set up a professional network with a Fritz!Box. It's a consumer grade device with bottlenecks as well as too few relevant features and settings. If you set up a network for 30 computers, you shouild at least have a professional SoHo device in place, with serious QoS settings, fully configurable local services, and capable of performing well.

If you really go with the Fritz!Box, neither use its switch nor its file serving features. Only use it for DSL and VoIP (optinally VPN).

Obviously, in this case, you could even buy a cheaper DSL gateway. You don't even need gigabit LAN to and from the router.

Placement of your internal server(s) and the throughput you expect there will be the key factors regarding your LAN.

  • Thanks for the info. Do you have any recommendation for such a router?
    – horen
    Nov 30, 2015 at 12:40
  • Product recommendations are actually considered off-topic here. But since you ask. If you want something carefully engineered in Europe, you can look into bintec elmeg (nowdays owned by Teldat) (I'm not affiliated). They have a reputation of excellent functionality and reliability, buf config can be tricky (lots of expert settings possible). If you want US/Asia products, your favourite search engine is your friend.
    – Run CMD
    Nov 30, 2015 at 12:45
  • Alternatively a Draytek would be a good option. Note that if your connection is VDSL2 you may need to ensure you support G.Vectoring in order to be compatible with your ISP.
    – Linef4ult
    Nov 30, 2015 at 13:49

It entirely depends on the amount of traffic you expect each client to generate, how much money you have to spend, how much you plan to 'futureproof' it and what kind of switches you're using in the other rooms. Also what will be happening on the network. For example, is it all in/out of network stuff, or is there also traffic between computers on the same network?

No you've given us something to work with, I'll answer.

There's no point going faster than Cat6/Gigabit because the router can only do gigabit. So a Cat6 connection from the router to the 3 switches will be fine. I would recommend using a switch in the router's place, and then connecting the router to the switch, as some routers have poor throughput.

Of course, if everyone is trying to use the internet at the same time, you will have performance issues, but these will be external, so nothing to do with the internal network. The only real bottleneck, unless you're doing a huge amount of file transfer on your file server, will be your internet connection, but otherwise, you'll probably be OK.

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