Nexus design question

[Zeeshan Siddiqui]

Hi All,

Can you pls help with my question below

IF we look at the drawing below / attached the 6509 below the dotted lines are the Layer 3 engines with odd vlan as root bridge on one and even vlans as root bridge on the second one on those switch all port will be in forwarding.

If we jump to the middle section we have two 6509 running as L2 switch only providing server connectivity and will have ports blocked as explained in the drawing below

The third section is a pair of NExus 5548 (Which is my question) as we can see there is VPC connectivity to the 6509s and to my knowledge one of the VPC will go in blocking as shown in red and one will be in forwarding to avoid any loops is this a valid design from a nexus prospective ?  we can not connect the nexus to the L3 devices directly because of the distance / no spare Fibre connectivity to those devices.

Your assitance is much appreciated

Kind Regards,

Zee

[Zeeshan Siddiqui]

All can one of the experts assist pls I have done few test in our lab and results look postive wanted to see if there are any design issues   (IF any ?)  thanks the diagram attached has the details

[Adnan Fakruddin]

It appears from your diag. that the two 6509 (L2 switches) are independent switches.

If you run VSS on these switches, VPC 50 would no longer be blocked, this would prove to be a better design as well as you're utilizing both L2 switches and meeting high availablity requirements at same time.

Similarly at L3, what is the config for the two switches? What is the logic for having different roots for odd and even VLANs?

[Zeeshan Siddiqui]

Many Thanks for your reply

Correct the 6509-L2 are independent switches.

The 6509 we run do not Support VSS.

The network was in place when I joined, the way its configured One L3-6509 is HSRP primary for odd vlan and is root bridge for those vlans the other is HSRP primary for even vlans and root for those vlans, the reason was to utilize both 6509 as we have more then 500 vlans running and the cpu utilization was an concern.

Pls confirm the existing Network diagram is a valid design or is it not recommended to have VPC in blocking as we have in Diagram attached

my question is with regards to VPC and nexus switching

agree as one VPC will be in blocking it will reduce our through out.