[ANNOUNCE] New Layer7 switching project

[Alexandre Cassen]

Hi Jinhua,
> How do you think about the performance of the new L7 switching system?
> Traditionally, the load balancer establishs a "pipe" between the client
> and the selected real server. In other word, the load balancer acts as
> a proxy. In this way, one TCP connection corresponds to two TCP 
> connections.
> Why not try other new manners to ensure the low cost of L7 switch?
>
> Besides, how do you think about the parallel workmode among the multiple
> load balancers? That is, active & ative. I think it's meaningful to 
> improve
> the Scalability of L7 switch.
You need to bridge the traffic in order to perform accurate layer7 
switching decision especially for HTTP/1.1 where multiple requests are 
sent into the same persitent connection. So L7SW must be a proxy but a 
high speed proxy. I mean, with the current design, socket API is used in 
order to have a compatibility layer with current proxy software and 
proxy design, but as soon as the socket are spliced the socket context 
for each connection is released. tcp_splice module create a layer4 
forwarding rules, so packets are switched from on side to the other just 
with the same performance as layer4 switching system (IPVS). We just 
have context switching overhead induced by client GET request relaying 
from client to server. Parallel balancing can be handled by an upper 
layer4 balancing system (IPVS) to a pool of L7SW.

cya,
Alexandre