Networking Layout Question


I have a few questions for all of you networking experts out there. I understand the fundamental concepts of networking in a home/office environment. I wanted to take the time to get some BASIC questions out of the way and would appreciate any feedback/responses. The questions are as follows:

1) Using a simple scenario, an office building has two floors with 100 computers on each floor. The first floor handles all accounting and financial data for the company and connects to a data backup server or file server. The second floor handles all research and development for the company and it too has its own dedicated data backup server or file server. This company uses a standard T3 connection to get out to the internet. I am assuming it would be wise to assign two subnets to the network (1 for each floor) to help avoid any traffic congestion and improve data flow/reliability?

2) In conjunction with question 1, using two subnets (1 for each floor), how would they need to be physically connected? For example, 1 router per floor, depending on how many ports the router has?

3) Being two separate sub-networks, how would they physically be connected to be able to get out to the internet and communicate with each other or each floor? In a basic scenario, using a basic router, you would have your cable/dsl modem plugged into the router, and the router would have DCHP enabled to assign local IP addresses. I understand you cannot have two routers both using DHCP due to address assignment conflicts (using 1 internet connection). Keep in mind, I want both subnetworks or floors to be able to communicate with each other and be able to access the internet. How would these routers be configured? I would like details on how the cable configuration or layout would be and any router settings that would make this possible.

Since two subnets would be used, each router would have to be configured using the appropriate subnet mask. Also, being each router needs to know its primary gateway to be able to access the internet, and we only have 1 internet connection, how would these two routers be configured? Moving back to a basic setup, if you connect an additional router to a network that uses 1 internet connection, DHCP would need to be disabled, making it a problem for managing this sized network of at least 200 hosts. Granted, I'm sure there is a workaround using this scenario and not comparing this to a home/office setup. But I'm trying to keep it basic.


So moving along, I'm just looking for a basic answer on how this would be done physically and logically. Keep in mind, one T3 internet connection, 2 floors with 100 hosts per floor with each floor using its own dedicated server. All hosts and equipment must be able to access the internet and communicate locally with each other. What's the cable setup and all router/network settings to accomplish this? Granted, I realize this is a broad scenario and many, many factors could come into play.

Your assistance would be appreciated and if I've repeated myself a few time, I'm sorry. I'm looking forward to your responses.
4 answers Last reply
More about networking layout question
  1. I'm not going to answer your questions in as much depth as you would like - on purpose - as basically I will not spoon feed other people with answers - you'll need to do some learning on your own - as unless you do, you will never really understand networking (if you have others provide you with answers all of the time).

    1) You do NOT need to use 2 separate sub-nets in this scenario, but depending on the number of additional devices on the network using TCP/IP (on top of the user PCs), then using 2 sub-nets is probably best for long term growth - depending on the numbers regarding how many IP devices in total and how those numbers will change over time.

    If the network is designed properly, there is no real need to use multiple sub-nets for traffic flow and limiting broad-casts etc - there's lots of other options that can be used for that - eg: VLAN configurations on your network switches.

    2) Why not just use a single multi-port router with a stack of network switches for each floor? The router will sit in between the 2 switch stacks and the internet gateway.

    3) You're complicating your thinking by comparing it to a home user scenario.

    You either split the single subnet into portions and configure DHCP servers to handle portions of the scope, or if you're using multiple sub-nets, have a DHCP server configured for each floor. You could probably use the router for this role, but if we're talking about a Windows network using Active Directory, then my advice is to install the DHCP server onto a Domain Controller and then integrate it with DNS for a dynamic DNS setup.

    A simple explanation of your scenario:

    3x 48 port network switches, per floor, chained in a stack, using either a dedicated stacking cable (like a 3Com Matrix cable) or trunked ports, or an etherchannel - with the first switch in each stack cabled to a port on the router, which has a 3rd port connected to your internet gateway.

    I haven't mentioned anything security related, but you would need to make sure the router is properly hardened and configured and I would be looking for at least 1, if not 2 firewalls to sit on the external side of your router between you and the internet.

    I'm pointing your in the right direction - but you're on your own from here as this could end up being a very long conversation and quite frankly I do enough technical consulting in my day job.

    My honest advice to you is you either need to do some serious learning of some kind or hand this job to someone who knows what they are doing (no offense intended).
  2. I appreciate you taking your time to advise me on this. You are absolutely right. I need to do some learning on my own. I currently have my A+ certification, which I've had for 6+ years. I'm currently reading up on Net+, which I'll be getting next. I know quite a lot about home/office networking, which is very basic. But obviously there is much more to it in different situations. With all I've learned thus far, I haven't been able to understand the correct setup of scenarios such as the one I listed. I'm probably getting way too ahead of myself, but such is curiosity. I'll be attending my local community college in a few months to tackle an Associates Degree in Networking, in which I'll be going over all this kind of stuff. But it's the curiosity that drives me into posting on forums, looking for answers. I do appreciate the response, and thank you for your time.

  3. I think muz_j might be talking about a layout kind of like the one I'm showing.
  4. Wow, this is an awesome layout picture. Thanks for posting this! :pt1cable:
Ask a new question

Read More

Routers Networking