... Denver-chicago Chicago-New York Denver-Salt Lake Denver-Dallas New York-Washington New York- Boston 1. 267 1. 023 807 537 794 235 19 4 $13 .535 $12 . 315 $11 .235 $6.285 $7.570 $4.775 $4.570 $1. 900 $1. 900 ... ny ti M - Nm 19 89, AT&T a dch v quc t IVPN l GSDN - Nm 19 90, MCI v Sprint a dch v VPN quc t VPN; Telstra ca ễ-xtrõy-li-a a dich v VPN rong nc u tiờn khu vc chõu Thỏi Bỡnh Dng - Nm 19 92, Vin ... tip khung (Frame relay) on Thanh Bỡnh, D01VT ỏn tt nghip i hc Chng Tng quan v VPN - Nm 19 95, ITU-T a khuyn ngh F -1 6 v dch v VPN ton cu (GVPNS) - Nm 19 96, Sprint v vin thụng c (Deustch Telecom),...