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Help with switch selection

I will preface this by saying I am a Mechanical Designer, our Electrical Designer is no longer with the company.

I have a situation that involves selecting the entire system for GigEthernet, equipment to equipment. I have no knowledge about switches, routers or the like. I am looking for help as to what parameters are needed in order to select the proper equipment.


Three story school building

50um backbone cable

Cat5e to the Work Areas

Need 10/100 to the desktops

Need T1 connection to incoming applications

There will be no fiber run longer than 500m

There will be no UTP run longer than 90m

Any and all help will be greatly appreciated. Thanks in advance.


Re: Help with switch selection

More info...

How many network connections per floor?

Are you looking for redundancy or a just get it to work?

Are you looking at VLANs?

Where are the servers and networking equipment located?

Is the Cat5e cable terminated at each floor?

Where is the fiber ran to and from?


Matt Bettis

Rising star

Re: Help with switch selection

Some of the questions that must be answered, in order to narrow the switching and routing equipment choices down to what's best for your situation:

>>>Three story school building

* How many wiring closets/distribution frames per floor?

* What kind of electrical power, space, and cooling/ventilation is available per closet?

* Is there one wiring closet/distribution frame that seems ideally suited to being the main one?

* Where is the telecommunications demarcation point (demarc) for the building?

* Is there a designated server room, with adequate space, climate control, and physical security (e.g. restricted access, with cipher lock or electronic card key access control)?

* Will the servers need Gigabit Ethernet connections? Over copper (Cat5 or greater) or fiber cable? How many?

* Will this be a data-only network, or will there be voice and/or video traffic running over it as well? (Determines whether you need uninterruptible power supplies, and how much capacity and run-time? Also influences some equipment choices, with respect to redundant components.)

>>>50um backbone cable

>>>There will be no fiber run longer than 500m

* Is this pre-existing 50/125-micron multimode fiber, or new installation? (Existing multimode is generally good to 220-275m using less expensive Gigabit SX optics; this distance can be extended to 550m using more expensive Gigabit LX/LH optics and mode conditioning launch/patch cables. Newer multimode may be able to take Gigabit even further, using only SX optics.)

* How many strands terminate in each wiring closet? And where do they go to?

* What kinds of connectors are used on the ends of the fiber? (ST, SC, LC, or MT-RJ are the most common).

>>>Cat5e to the Work Areas

>>>Need 10/100 to the desktops

>>>There will be no UTP run longer than 90m

* Does the Cat5e cable run back to the nearest wiring closet/distribution frame on the same floor?

* How many runs/drops total from the desktop locations back to each closet/frame? How many do you expect to be actively used, per closet/frame? (This determines 10/100 switch port count requirements.)

>>>Need T1 connection to incoming applications

* Is this the Internet connection, or a private leased line/wide area network link?

* Would a higher speed than 1.5 megabits per second be needed?

Hope this helps.

Not applicable

Re: Help with switch selection

Thanks for the help, here are the answers to the questions:

On the first floor, there is a MDF that connects to the IDF of the 2nd and 3rd floors. As well as, there are 3 closets on each floor.

This is a new build, so the space is up to us.

The demarc point will be in the MDF on the main floor.

Server farm will be on the main floor in the MDF

The spec if for 10/100, but migrating to Gig eventually. The client is requesting copper and fiber data ports. Around 900 copper and 300 fiber drops are located in the building.

Only a data network.

This will be new 50um, and the distance will not be a problem.

Strands terminating, I would imagine, should depend on the switches? No?

ST connectors into the media outlets, but there will be PP to connect btw switch.

The Cat5e, I hope, would only run from nearest closet to media outlet.

There are a maximum of 140 copper drops coming from the switch at the closets. We are estimating that 75% will be used.

The T1 is the internet connection from an outside source.

I am over budgeting the estimated usage at 2meg/s.

Thank you for your insight and help.

Not applicable

Re: Help with switch selection

My other question is about routers. How would I know when/where to insert them into the network?

Thanks again for the help.


Re: Help with switch selection


Router is the connecting point to your LAN and to Outside world. You want to have only one T1 connection on leaseline. for the backup for this part, you can go for ISDN Line. For this config, you can go abt to One Cisco 1750 Series Router with one WAN card and one ISDN Bri card. If lease line fails, now ISND will take care of the connectivity. For the redundancy part on Link the above is enough. But if you want to have hardware (If one Router or wan card fails) redundancy, then have two cisco 1750 series Router with same config, and we can run HSRP ( Hot standby Routing Protocol) between them.SO that your network will be up and live for all the time, even your LL fails or your card fails or your Router fails. Keeping both the Routers in different UPS supply, will add more redundent on it.

Thankx for giving an oppurtunity to help you.

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