In general-purpose parallel and distributed systems,
performance of the protected and virtualized 
user-level communications/synchronizations is the most crucial issue
to realize efficient execution environments.
We proposed a novel high-speed user-level communications/synchronizations
scheme ``Memory-Based Communication Facilities (MBCF)'' 
suitable for the general-purpose system
with off-the-shelf communication-hardware. 
This paper describes packet formats of the MBCF with 100baseTX 
communication interfaces. Next, the paper shows basic performance of
the MBCF/100baseTX using test programs and a logic analyzer which 
measures wave forms of 100baseTX interface.
Finally, we develop another MBCF interface on UDP/IP in conventional
operating systems and compare the performance of our original MBCF
with that of the MBCF/UDP.