Network Design Advice

TheBishop, a few questions for you - other contributions appreciated too

the usual approach is to have a 'core' of one or more switches with connections out to 'distribution' switches out on the floors.

In my case, I have a core switch that is uplinked to switches on the different floors. Is it good practise to uplink switches on the floors together then to the core switche(s)?

i.e. switch_on_floor1 <-uplink-> switch_on_floor2 <-uplink-> switch_on_floor3 <-uplink-> core_switch

OR

Uplink each switch directly to the core switch without going through any switch

switch_on_floor1 <-uplink-> core_switch
switch_on_floor2 <-uplink-> core_switch (same core switch)
switch_on_floor3 <-uplink-> core_switch (same core switch)

Would interconnecting switches e.g. switch1<->switch2<->switch3 to coreswitch/router etc affect performance/speed of traffic flow? Also, does it matter which floor the core switch is installed on i.e. top most floor/ground floor

Make sure your core device(s) are capable of handling the throughput that will be generated by all your users and whatever servers/internet connections you wil have. Remembe that each distribution switch only carries the traffic from that floor, but the core needs to be capable of handling the lot.
Similarly you want core-to-distribution uplinks that are big enough for the aggregated bandwidth of a floor full of users.

By this I think you mean using a "high-end" switch at the core and then low-end one's at the distribution/access? In my case I have used a Cisco 2950 at the Core and basic non-cisco switches on each floor. What do you think? I would have preferred having the Cisco 2950 on all floor but unfortunately constrained by the cost. Clearly a fan of Cisco gears.

I hope my question makes sense.

Your other comments make sense to me.

thanks

It makes much more sense to connect each distribution switch directly to the core on its own link. If you cascade the distribution switches then you are reducing your resilience (failure of a distribution switch also cuts off the link to the other distribution switches downstream) and you are also placing an additional load on the distribution switches nearest the core as they have to handle traffic for the other floors and not just their own.
You have understood the second point correctly; the core would be a "high-end" device compared to the distribution switches. It's fine to put Cisco in the core and non-Cisco on the floors, just make sure that things like spanning tree and trunks/etherchannels will inter-operate correctly between the different vendor's kit - I'd set it up as a test rig on a bench first to prove the point. Most reasonable vendors will let you test it first.

Going on design makes you think about a couple of things:

-Redundancy (try to elimante spofs as much as possible)
-Oversubscription (Allowing all computers 1000mbit will demand much more of your uplinks then 100mbit ofcourse)
-IP Plan (pretty simple in this one. /24's for a floor would do.
-Availability (kinda the same as redundancy, difference is that endpoints are usually connected by only 1 UTP. No Etherchannels used for users ).

probably I am forgetting a couple of points.. but, I would say:

Every floor could consist of 2*48 port switches or 3*24 port switches.
Choice in this one could be availability. What if 1 switch would die, loose power.. whatever. With 3 switches, with a loss of 1 switch you have a maximum of 24 ports lost.
With the 2 switches 48 ports.

Redundancy. You probably want to connect your floor-switches as L2 switches (Cisco 2960's could do fine). Within the 2960 you can use SFPs for upload towards your core. In your core you have SVIs configured and there you can route between the floors.

Besides users, I suppose there are also servers. Are those in conditioned areas? Thats probably the area where your core (2x3750 would do. Why 2x? Redundancy.)
Ofcourse you could go for 2x 6500's with VSS.. but thats a bit overkill hehe .

So, that would be 2/3 switches per floor as L2 (access-layer) switches. And 2x 3750 (l3) switch as your core. 3750's are pretty powerfull switches and can handle this without any problem. I believe they have a backplane of 68Gbps... would be more then enough to support this.

I think the biggest concern... are the coins .
Also things as security can come into place. Do the floors have to be connected or seperated. Access restricted or freely allowed? How do they connect towards the internet? a lot more of question...but I think those are not the question here.

Hope it helps ya a bit.