Last April I posted some information about the z/VSE Linux Fast Path (LFP) function. I also pointed you to a related article. The blog entry is here.
With LFP a TCP/IP application on z/VSE can communicate with a small program (LFP daemon) running on Linux on z Systems. The daemon communicates through the Linux TCP/IP stack with the network. LFP may communicate between LPARs or z/VM guests. A Linux instance (distribution) is required. LFP does not require a TCP/IP stack on z/VSE, however.
The z114, z196, zBC12, zEC12 and z13 processors also provide a feature called z/VSE z/VM IP Assist (VIA), that can be exploited by LFP. With VIA the processor provides the functionality to communicate to the network without having a Linux distribution installed.
If you are interested in VIA or want to use VIA. This function is described in the z/VSE TCP/IP Support book. You can find that book here.
There is a technical article about VIA too. It is here.