3Com 3C13636 Configuration Manual page 1207

3Com Router 3000 Ethernet Family
Configuration Guide
III. Classified by networking model
1) VLL
Virtual Leased Line (VLL) is emulation to traditional leased line services. By emulating
leased line over IP networks, it provides asymmetric and low cost "DDN" service. From
the view of end users of VLL, it is similar to traditional leased lines.
2) VPDN
Virtual Private Dial Network (VPDN) means implementing virtual private network by
employing the dial-up function of public networks (e.g. ISDN and PSTN) and access
networks, to provide access service for enterprises,
businesspersons.
3) VPLS service
Virtual Private LAN Segment (VPLS) interconnects LANs via virtual private network
segments in virtue of IP public networks. It is an extension of LANs on IP public
networks.
4) VPRN
Virtual Private Routing Network (VPRN) interconnects headquarters, branches and
remote offices via network management virtual router in virtue of IP public networks.
There are two kinds of VPRN services: VPRN implemented using traditional VPN
protocol (IPSec, GRE, etc.) and VPRN by means of MPLS.
IV. Classified by working layer
1) L3VPN: including BGP/MPLS VPN, IPSec VPN, GRE VPN, etc.
2) L2VPN: including MPLS L2VPN in Martini mode, MPLS L2VPN in Kompalla mode,
MPLS L2VPN in SVC mode, VPLS and static CCC configuration.
3) VPDN: including L2TP, PPTP, etc.
3Com Corporation
1-6
Chapter 1 VPN Overview
small ISPs, and mobile