Vendors proposed a lot of designs on the data center setup. Attached please find the best two designs for the discussion (design 1 and design 2). Below is the description of Data center / DR site and offices floor for your reference:
7/F of Data center is meet me room for connecting the fibre cables and core switches
15/F and 22/F is the office floor to provide IT professional services (PC, printers etc)
5/F is DR site where is another building next to Data center
The bandwidth of all up links / cross links is 10G
Two 3750 are stack together with stacke cable
1. Which design is better? and why?
2. Some engineer suggest to remove the inter fibre cable (please find the "A" in blue color) between 15/F and 22/F . The network would be more stable. Is it correct? pls advise
I share Leo's doubts about the use of C4500 with multiple 10GE links: they are not right devices for this job in a data center because they don't give enough 10 GE port density and they are oversubscribed.
2,5: 1 oversubscription for the 6 Tengiga linecard.
each old linecard 6 Gbps per slot per direction.
new E series linecard provides 24 Gbps per slot so 6 ports means 60 Gbps / 24 = 2,5
the WS 6704 on C6500 provides you 1:1 = no oversubscription
for a campus would be fine but for a data center with expected high traffic volumes would be better to avoid oversubscription.
Hope to help
I'd go for #2 but I would like to remove the "A" link in between 15/F and 22/F. Why? Because it provides true redundancy in case the first switch should fail. If you want proper redundancy make sure the fibre optic link is from a different pipe or physical cable.
Regarding the use of 4500 with 10Gb, some would say the Sup6 is sufficient but I'd go for a pair of the 6500 with Sup720-VSS and 6704 10Gb blades. Then you can use the 4500 with Sup6 for the DR site.
I'd like to remove the "A" cable because you can cause an STP loop. You already have two links for the Etherchannel plus another one going to the DR site. Adding a fourth ain't going to speed the network.