BIG Question for a willing soul

Would you be willing to review a small network design I am doing for a networking class and tell me where or what I might need to change or do differently. I really like this networking but this is my first class so I'm a novice with more desire than knowledge at this point. The only catch is the assignment is due tomorrow midday. I'm not asking you to do it for me I would just like you to make sure I'm doing what would work, and make suggestions. I have some areas highlighted but that does not mean the rest is not without errors or questionable decisions. I will try to make it easy so it does not take much of your time as I know you probably have better things to do, but this might be fun and interesting for you. Can you remember back when you were learning this.

It has one location in Colorado with a main office (110 computers) and a plant ( 20 computers). Another office in Missouri having (50 computers). The Company is a class B organization and it seems the instructor wants us to do some subnetting. I am to design the entire network from the core, distribution, access and even to the WAN. Here is what I have.

Colorado Office Location (110 computers in service)
Core Layer:
Architecture: Routed backbone (bus) using layer 2 router ??? should I use layer 3 here instead?
Recommended speed: 1000Mps/1gbps
Cable type: 1 GbE fiber over Ethernet (10GbE?) //should I go with the 10GbE and a different device
Device recommendations: Ethernet 1000Base-F, 4 port router

Distribution Layer:
Architecture: Switched (star) using layer 3 switches
Recommended speed: 1000Mps/1gbps
Cable type: 1GbE on fiber from the core to the switches, Cat6 from the switches to computers.
Device recommendations: Layer 3 Ethernet switches 10/100/1000Base-T, 1-48 port, 2-24 port, 1-16 port.

Access Layer:
Architecture: Switched (star) using layer 2 switches
Recommended speed: 1000Mps/1gbps
Cable type: Cat6, several patch cables
Device recommendations: the 100 computers

Colorado Plant Building (20 computers in service)
Not sure what to do here as far as connecting the two buildings, I’m assuming the plant is a short distance from the main office bldg. It won’t need the core layer will it?
The router can be either located in the main office or plant I suppose; the same for the switch possibly, not sure.

Core Layer:
Architecture: Switched (star) using layer 3 switches //this is not right, I can’t mix this with the Cat6
Recommended speed: 1000Mps/1gbps //cable and patch panels. Something’s not right
Cable type: Cat6 //with this setup I think. HELP!!
Device recommendations: Cat6 cable, 20 Cat6 patch cords, Cat6 patch panel 24 port
Assumptions: Using Cat6 due to the fact it is good for noise or environments more prone to interference

Distribution Layer:
Architecture: Switched (star) using layer 3 switches
Recommended speed: 1000Mps/1gbps
Cable type: Cat6
Device recommendations: ??

Access Layer:
Architecture: Switched (star) using layer 2 switches
Recommended speed: 1000Mps/1gbps
Cable type: Cat6
Device recommendations:

Missouri Office Location (50 computers in service)
Core Layer
I will assume this can be set up the same as the Colorado office

I have no idea of the WAN connection between Colorado and Missouri or where to do the subnetting. I have a router located between the core and distribution, one from the main office to the plant (this may not be needed I'm not sure). My understanding is only the routers can be subnetted, the switches kind of do this by themselves.

I hope you will be willing to help out, I would like to find an internship in this field next semester, with hope of working on the CCENT certification soon after.

Thank you in advance for willing to help.
3 answers Last reply Best Answer
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  1. Looks like you are making it overly complex.

    Why would you make multiple switch layers for such tiny offices. You just buy a 48 port switch and you are done. Even the main office this is not enough machines to even worry about it. Run a couple of stacked switches or a larger switch with multiple 48 port boards. You really only need multiple layers of switches when you have a environment where you cannot have all the cables terminate in one location. Even if you had servers you would just chop off another vlan on the switch not worth the hassle of putting in separate switches.

    This also avoids all the questions of link speeds between the layers. You run everything across the back plane of the switch.

    How you hook up the WAN I have no clue. The common way is to call up your favorite telco and buy a managed MPLS network. They install the routers ask you for your subnets and it all routes you do nothing. It tends to be no more costly than buying and managing the circuits yourself.

    Are you sure they even wanted you to worry about switch layers, or did they just want you to chop a /24 into blocks that would work. You need all kinds of small networks if you route between your switch layers.
  2. I have a tendency to over complicate things and I thought I was because the more I worked on it the more confused I was getting. Nothing was given as far as the topology, architecture or anything except to design the IP Subnet Structure for a class B organization. The address was up to me, I had chosen then I was suppose to determine the subnet mask which I have as The the other requirement is to determine how many subnets I would need.

    I'm assuming both office locations can be set up the same, not sure how to do the plant though. It is very small and either attached or next door; I have to make an assumption on everything and document why.

    So are you saying one router each at the two office buildings? And for the main location with 110 computers use a couple 48 port switches. What about the cable I had would this be good then and what about the speeds for the backbone/core, distribution and access layers. I'm not picturing what this will look like.

    Thank you for you helpfulness and input
  3. Best answer
    Since this is fake and there is no data I will just make the common assumption.

    The 2 location in colorado are in the same business part and you can get a fiber connection between the buildings.
    The remote office is something like a sales office and uses very little bandwidth. You purchase a manged t1 (1.5m) circuit to this office. The company you buy it from provides the router that drive run the circuit and hand it to you on 100m ethernet. If you feel it needs more bandwidth you have the vendor deliver it in multiples of 1.5 t1 circuits. This is also why you buy these manged it is the vendor that needs to solve how exactly they deliver this. They have the staff to monitor 24x7 and fix it.
    ...and if they say its not a sales office then they have to tell how much bandwidth per user they expect between the home office and the remote...

    Your central office you have a choice. Buy a single large switch that has say 150 ports or buy 3 48 stackable switches. Stackable switches use special interconnect cables to make they appear as a single switch. You would need at least one port with fiber to use to connect to the remote building.

    The office that is nearby you use a 24 port switch with fiber and connect it back to your main office.

    The 50 person office sucks because switches comes 48 port or 24 never 50. You could again just buy a big switch that has lots of ports. Or you could buy a 48 and a 24 port stackable switch to get 72 ports. In either case the appear as a single switch.

    I would use all layer 3 switches. There is no concept of core/distribution/access. You have a single switch at each location(or what looks like a single switch) and you don't worry about capacity the backplanes of these switches have more than enough capacity to handle a couple hundred users.

    For subnets that I will leave to you. You can easy chop a single /24 up for all three location. Be aware you need a 3 point to point subnets 1 over the fiber and 1 at each location to connect to the vendor router.

    The only people that think all sites need core/distribution/access are companies that want to sell you lots of equipment. I generally only use that design where I have very large buildings with many floors..generally over 1000 users.
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