Cisco Virtual Service Data Path (vPath) is the service intelligence
embedded in the Cisco Nexus 1000V Series switch.
vPath provides the forwarding plane abstraction and programmability
required to implement the Layer 2 to Layer 7 network services such as
segmentation firewalls, edge firewalls, load balancers, WAN optimization, and
others. It is embedded in the Cisco Nexus 1000V Series switch Virtual Ethernet
Module (VEM). It intercepts the traffic whether external to the virtual machine
or between virtual machines and then redirects the traffic to the appropriate
virtual service node (VSN) such as Cisco Virtual Security Gateway (VSG), Cisco
ASA 1000V, Citrix NetScaler 1000V, or Cisco Virtual Wide Area Application
Services (vWAAS) for processing. vPath uses overlay tunnels to steer the
traffic to the virtual service node and the virtual service node can be either
Layer 2 or Layer 3 adjacent.
The basic functions of vPath include traffic redirection to a virtual
service node (VSN) and service chaining. Apart from the basic functions, vPath
also includes advanced functions such as traffic off load, acceleration and
vPath steers traffic, whether external to the virtual machine or from a
virtual machine to a virtual machine, to the virtual service node. Initial
packet processing occurs in the VSN for policy evaluation and enforcement. Once
the policy decision is made, the virtual service node may off-load the policy
enforcement of remaining packets to vPath.