Design Advice - Please Help!

[pmajumder]

Hi All,

I am looking for any design advice, ideas, for an upcoming project as follows:

There will be 2 6509 switches for core (Collapsed Backbone)

These 2 core switches will connect to 2 more 6509’s for use as server distribution switches

The core switches will also connect to 7 4506’s in the wiring closet.

The main question I am struggling with is what is the best way to achieve VLAN load balancing & redundancy to the wiring closet, and the server distribution layer (We will have about 20+ VLAN's)?

Secondly, should I connect our firewalls & Mainframe (via OSA’s) to the Core or to the server distribution layer? Pros/Cons of one vs the other

I have read numerous Cisco Technical documents including those that pertain to design, but I still feel that I need some detailed feedback from those that have implemented a similar design in a Data Center.

Any help would be very much appreciated.

Regards

Pradeep

[lgijssel]

Hello Pradeep,

Interesting case. I would say that there is one fundamental flaw in the proposed design: The aggregated bandwidth of the servers will certainly be a lot bigger than the total link capacity between the 6500's. This will limit network performance under heavy load.

Therefore, a collapsed backbone may not be the best solution. You may achieve better performance with a conventional switch-block according to the hierarchical model. This will allow you to make better use of the bandwidth of your switch-backplanes. There will be less blocking in this type of design. You can also achieve the redundancy level that is characteristic for the hierarchical model. This redundancy is achieved by the combined use of HSRP and spanning tree.

Regards,

Leo