why disable pva for layer2/3 npath v/s

PVA acceleration is disabled only for L3 nPath virtuals.

 

This is required for the GRE or IP-IP tunnel - the traffic cannot be handled at the switch, but must traverse TMM to be encapsulated for routing to the server.

 

K13403: Configuring L3 nPath load balancing and monitoring

 

Description

 

L3 nPath routing allows traffic to be load balanced over a routed topology. In this deployment, the server sends its responses directly back to the client instead of the BIG-IP system, even when the servers and any intermediate routers are on different networks. This load balancing method uses IP encapsulation to create a uni-directional outbound tunnel from the server pool to the server. The origin web server unencapsulates the original client IP information, which is then used to route the return traffic directly to the client.

 

The available encapsulation protocols are GRE and IPIP. The protocol you choose for building the encapsulation tunnel may depend on the requirements of your environment.