We are going to be using a pair of Cisco Nexus 7010s to act as both our data center aggregation layer and the core layer. We will accomplish this via two VDCs, one for the core layer and one for the aggregation layer.
I know that if we are doing VPCs between the access and aggregation layers that we need a VPC Per Link (and peer keep alive link) between the two aggregation layer contexts, but if the connection between the aggregation and the core is purely layer 3 (OSPF), then I don't think we need a VPC peer link between the two core VDCs, Am I correct?
Is there any chance that a VPC Peer Link is requiredbetween core VDCs even without VPCs between core and aggregation (strictly layer 3) just to keep the Active/Active and Primary/Secondary (not STP, VDC "synchronization") processes funtioning properly?
I'm also doing with a VDC-core/VDC-agg model on the same chassis with 2 Redundant Cisco Nexus 7010 and a pair of Cisco 6509 used as a Service Chassis without VSS. Each VDC Core have redundant link to 2 PE based on Cisco 7606. But after reading many design document of Cisco, I'm asking what is the need of a Core Layer in a Data Center especially if it is small or medium size with only 1 aggregation layer? What was your driven for this core?