Cisco Cisco Prime Virtual Network Analysis Module (vNAM) 6.0 White Paper

FabricPath can be implemented in a variety of network designs, from full-mesh to ring topologies. In 
VMDC 3.0.X design and validation, the following DC design options, based on FabricPath, were 
considered:

Typical Data Center Design—This model represents a starting point for FabricPath migration, 
where FabricPath is simply replaces older layer 2 resilience and loop avoidance technologies, such 
as virtual port channel (vPC) and STP. This design assumes that the existing hierarchical topology, 
featuring pairs of core, aggregation, and access switching nodes, remains in place and that 
FabricPath provides L2 multipathing.

Switched Fabric Data Center Design—This model represents horizontal infrastructure expansion 
of the infrastructure to leverage improved resilience and bandwidth, characterized by a Clos 
architectural model.

Extended Switched Fabric Data Center Design—This model assumes further expansion of the 
data center infrastructure fabric for inter-PoD or inter-building communication.

These are discussed in detail in VMDC 3.0 documentation. The 

 is publicly available, 

while the Implementation Guide is available to partners, and to Cisco customers under NDA.

While the logical containers discussed in VMDC VSA 1.0 may be implemented over a traditional 
classical Ethernet or FabricPath fabric, to constrain scope this release is based solely on the Typical Data 
Center FabricPath design option previously validated in VMDC 3.0/3.0.1.

A Typical Data Center design is a two-tier FabricPath design as shown in

 VMDC 

architectures are built around modular building blocks called PoDs. Each PoD uses a localized Services 
attachment model. In a classical Ethernet PoD, vPCs handle L2 switching, providing an active-active 
environment that does not depend on STP, but converges quickly after failures occur. In contrast, 

 shows a VMDC PoD with FabricPath as a vPC replacement.