A predominant ('base') scheme currently used in many circuit-switched
LAN-WAN gateway applications is based on device-driver LAN redirection
s. Various functional and performance deficiencies associated with the
LAN redirection (base) scheme and an RPC programming interface are de
scribed. This RPC definition supports the base scheme, as well as anot
her ('enhanced') scheme. The enhanced scheme overcomes the various out
lined functional deficiencies associated with the cited implementation
s of the base scheme. Implementations of these two client-server appli
cation schemes on top of the IEEE portable operating-system interface
and the Open Software Foundation RPC are described for both schemes. P
erformances of these two schemes are compared, both based on a simplif
ied Markov chain model and on actual implemtations and long-duration e
xperiments. Some of the similarities between the predictive simple-mod
el behaviors and the actual experienced results for the applications a
re encouraging. This experience shows that the described RPC programmi
ng interface is a reasonable candidate for immediate practical impleme
ntations on heterogeneous systems.