Automated PBR and Route Health Injection with RISE

RISE is an innovative architecture that logically integrates an external service appliance such as Citrix NetScaler or the Cisco Prime NAM so that it appears & operates as a service module within the Nexus 7000 Series switches.

RISE integration with the Citrix NetScaler provides features like Route Health Injection (RHI) and Automated PBR (APBR) which allow easy configuration to redirect client and server traffic to the load balancer.

Automated Policy Based Routing (APBR)

Existing solutions to have server traffic return to the load balancer are Source NAT and PBR. Using Source NAT causes applications (server) to lose the visibility to client IP, burning IP address pool for Source NAT configuration and manual configuration. Policy Based Routing (PBR) requires complex initial configuration from the user (susceptible to human errors), configuration updates when a server is added or removed which can be cumbersome as the number of network devices and servers/VIPs grow.

Auto PBR eliminates the need for Source-NAT or manual PBR configuration in an one-arm mode design of load balancers
Preserves client IP visibility for applications/servers without the need for manual PBR
APBR feature allows the NetScaler to program policies on the N7K server-facing interfaces to redirect return traffic to the NetScaler appliance set up in one-arm mode
NetScaler passes information about real servers to N7K via the RISE channel and a policy is applied on the N7K interface through which the real server can be best reached
Since it is desirable to change the SRC IP to VIP for the return traffic, the APBR policies redirect traffic to the NetScaler IP without modifying the packet
The NS appliance will then direct the packet to the client by changing the source IP to VIP