.PS
.ps 20
## figure 3
B1:	box shaded
B2:	box invis with .s at (B1.n.x, B1.n.y+lineht) "SERVICE" "OFFERED"
B3:	box invis with .n at (B1.s.x, B1.s.y-lineht) "SERVICE" "USED"
##
B4:	box dashed with .w at (B1.e.x+5*linewid, B1.e.y) "PEER"
B5:	box invis with .s at (B4.n.x, B4.n.y+lineht)
B6:	box invis with .n at (B4.s.x, B4.s.y-lineht)
##
	arrow from B1.n to B2.s
	arrow from B3.n to B1.s
	line <- -> dashed from B1.e to B4.w "PROTOCOL" ""
	arrow dashed from B4.n to B5.s
	arrow dashed from B6.n to B4.s
##
.PE