Solved: two Campus design

anitachoi3 · ‎03-13-2010

Hi,

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

rdgs

Leo Laohoo · ‎03-14-2010

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.

View solution in original post

Giuseppe Larosa · ‎03-14-2010

Hello Anita,

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.

http://www.cisco.com/en/US/prod/collateral/modules/ps2797/ps9294/product_data_sheet0900aecd806df543_ps4324_Products_Data_Sheet.html

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

Giuseppe

View solution in original post

Reza Sharifi · ‎03-13-2010

anitachoi3 wrote:

Hi,

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

rdgs

Hi Anita,

Assuming 3750s are layer-2 only and 4500s are layer-3

I would keep the routing separate per floor. On 15th and 22 floor since the 3750s are stacked connect one 10Gig from 3750-A to one 4500 and one from 3750-B to the other 4500 or Etherchannel sine you have 2 10Gig on each 3750. This way you do not need to connect the 3750 together.

HTH

Reza

anitachoi3 · ‎03-13-2010

Dear Reza,

Attached please find the design 3 you propose from preceding message. Please correct me if you find the design 3 not to match your idea.

There are four questions and I would like to seek for your advice.

1. Is it the design 3 the best among three network design solution? there is layer 2 Ethernet loop in each floor until the inter fibre cables between two core switches (4506) are in block mode. Is it correct?

2. If the inter floor fibre cable between 15/F and 22/F is removed from both design 1 and design 2, what is the best from the three designs?

3. If the inter floor fibre cable between 15/F and 22/F is kept, does it cause the network unstable? and why?

4. How many alternative paths in block mode would be suggested to be followed or guardian? and why?

rdgs

Giuseppe Larosa · ‎03-14-2010

Hello Anita,

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.

http://www.cisco.com/en/US/prod/collateral/modules/ps2797/ps9294/product_data_sheet0900aecd806df543_ps4324_Products_Data_Sheet.html

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

Giuseppe

Leo Laohoo · ‎03-14-2010

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.