Yes, on the 2nd computer I use a Tascaam US1800 to process the VSTi's and return the audio output to the 1st computer using the Steinberg UR824. rtpMidi does only transmit the midi and it does require additional audio cards to be on those computers it sends to. The ultimate solution will be moving towards the Vienna Pro setup as it does not require the sound cards and contains current support for both windows or a mac version setup.
At this point I have tested and run successfully about 50 channels of midi being sent via my wifi router through rtpmidi. I have all my midi keyboards and controllers plugged into the first computer, and the 2nd receives from the first through rtpMidi.
To make it real simple, for me, the first computer I called the session was something like this: MasterSend1, and then on the 2nd computer I called the session Receive1, and then connected those two sessions via the rtpMidi. Each session I have found can broadcast up to the normal 16 channels of midi and be received on the 2nd computer by adjusting the appropriate session and midi channel to match it.
I did have a few problems with running rtpMidi on a Windows 7 I3 laptop, only about 4 yrs old, it dropped midi notes occasionally when using it to run Cubase 7 and send the midi through rtpMidi. I have access to a an older macbook pro, about 5 yrs old, and it worked perfect to run Cubase 7 and send the midi to the 2nd computer running windows 7 with a core I7 setup.
In discussing the original topic I have discovered the VST system link has it weak points as it requires additional digital audio cards that can transmit. The Vienna Pro will beat it all around as it can network without additional cards. Too bad Cubase has not changed their system as it could easily bring more people into their DAW setup.