The Nuage Virtual Services Platform (VSP) supports a service chaining function that ensures traffic traverses a number of services (also known as Service Functions) between application hosts (FW, LB, NAT, IPS/IDS, and so on.) if the operator needs to do so. In the DC, tenants want the ability to specify these functions and their sequence, so that services can be added or removed without requiring changes to the underlying application.
This service chaining function is built based on a series of policy based routing/forwarding redirecting rules that are automatically coordinated and abstracted by the Nuage Virtual Services Directory (VSD). From a networking perspective, the packets are hop-by-hop redirected based on the location of the corresponding SF (Service Function) in the DC fabric. The location of the SF is specified by its VTEP and VNI and is advertised by BGP-EVPN along with an Ethernet Segment Identifier that is uniquely associated with the SF.
For more information about the Nuage Service Chaining solution, see the Nuage VSP documentation .
The 7750 SR, 7450 ESS, or 7950 XRS can be integrated as the first hop in the chain in a Nuage DC. This service chaining integration is intended to be used as described in the following three use cases.