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How to choose a distribution switch?

ausarian1
Level 1
Level 1

Good day guys!

I have a question in mind and every input would be greatly appreciated.

My boss told me to create a sample data network design for 300 users. I need to choose which access and distribution layer switch to use(there will be no core switch).
My problem is, I dont know how to choose the correct distribution switch.

Please someone tell me what are the things to consider in when choosing your distribution layer switch. 

e.g.

Lets assume that I will use these 3 switches on each floor
2x WS-C2960X-48TS-L
1x WS-C2960X-24TS-L

Those three access switches should be sufficient for 100 users and the desktops will be using 100mbps LAN cards. 

The data sheet says the Forwarding bandwidth is 108 Gbps for the LAN base version. Since I will be using 100mbps desktop lan cards, My forwarding bandwidth should be (please correct me if im wrong especially with the term I used)
48 port switch:
48ports*100mbps+4000gbps SFP*2full duplex = 17600mbps or 17.6Gbps forwarding bandwidth (please tell me the correct term for this or the correct calculation)

24 port switch:
24ports*100mbps+4000gbps SFP*2full duplex = 12800mbps or 12.8Gbps forwarding bandwidth (please tell me the correct term for this or the correct calculation)

Assuming we will use the wirespeed then the total bandwidth that will pass through the trunk link from the access layer to the distribution layer will be:
17.6+17.6+12.8 = 48gbps per floor

My questions are:
1. What distribution switch do I need to use?
2. What are the factors do I need to consider when choosing a distribution switch. Please tell me in steps about which should I compare and look for 1st. I mean based on our calculations we will have 48gbps total of forwarding bandwidth from the access switch to the distribution. How will I know if the port of the distribution switch or the distribution switch itself can handle it?
3. What is a switch forwarding rate and how can I use it when choosing my distribution switch?

Thank you so much in advance for the inputs! 

2 Replies 2

Leo Laohoo
Hall of Fame
Hall of Fame

There is no such thing as a "FastEthernet version" of a 2960X.  

 

Your computation is flawed.  You're going to tell me you've got users which can push 100 Mbps/1 Gbps of traffic 24-hours a day?   

 

Will the (theoretical) switches be located in the same floor data cabinet or spread all over.  

What are the factors do I need to consider when choosing a distribution switch.

Your budget plays a significant part.  What's your budget like?

michael.wing
Level 1
Level 1

Hi ausarian1,

The first things I would conciser when looking for a distribution switch would be as follows.

  1. What feature set will it need to perform?
  2. What type of traffic will the distribution switch need to work with?
  3. Are you going to be implementing redundancy within the distribution layer?
  4. Where are you going to be installing the switch? In the office or in a secure room?
  5. Other than access switches and servers what else will the switch be providing connectivity for?

When you conciser all of the above you will have a better idea of the feature set of the switch you need, how many ports/what type of ports are required and possibly passive cooling (switches can be very noisy).

The following link should give you a good idea of the current offering from Cisco with data sheets;

http://www.cisco.com/c/en/us/products/switches/index.html

If you have a really tight budget for this project, then it might be worth while looking on somewhere like eBay for an end of life product.

Michael

ps. Don't get so hung up on bandwidth throughput, you will never achieve the advertised bandwidth of a link, as you will always have over heads and you will never be utilizing the full capacity of every link on your network all the time. Instead think about the jobs of the people that will be using this network, are they Salesmen? Accountants? Graphic designers? Programmers? this will give you an idea of what type of traffic to expect on the network and the typical file sizes you should expect to see transferred.

It would also be worth while approaching a couple of preferred Cisco re-sellers in your area(IntecMicro/Computer2000/Azlan/Insight ect) these companies typically have Cisco account managers, if you send them over the details of your research they will be able to provide you with their suggestions. Always a good idea of have as many options on the table as possible.

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