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

QoS is a key to service assurance because it enables differentiated treatment of specific traffic flows. 
Differentiated treatment ensures that critical traffic is provided sufficient bandwidth to meet throughput 
requirements during congestion or failure conditions.

 illustrates the different traffic flow types defined in previous VMDC releases. These traffic 

types are organized in infrastructure, tenant, and storage traffic categories.

Infrastructure traffic comprises management and control traffic, including VMware service console 
and vMotion communication. This is typically set to the highest priority to maintain administrative 
communication during periods of instability or high CPU utilization.

Tenant traffic can be differentiated into front end and backend traffic, with service levels to 
accommodate various traffic requirements in each category.

The VMDC design incorporates Fibre Channel and IP-attached storage. As shown in 

, 

storage requires two subcategories, because these traffic types are treated differently throughout the 
network. Fibre Channel traffic, by definition, requires a “no drop” policy, while Network File 
System (NFS) data store traffic is sensitive to delay and loss.