Virtual Leased Line
Virtual Leased Line (VLL) is a way to provide Ethernet-based point to point communication over IP/MPLS networks.
The term Virtual Leased Line is also used to describe a point to point bonded connection using the Broadband Bonding technology. This implementation is bonded in layer 4.
In the industry, the technology is also referred to as Virtual Private Wire Service (VPWS) or EoMPLS (Ethernet over MPLS).
VLL uses the pseudo-wire encapsulation for transporting Ethernet traffic over an MPLS tunnel across an IP/MPLS backbone.
Types of VLLs
There are 5 types of VLLs:
- Epipes: Emulates a point-to-point Ethernet service. VLAN (Virtual Local Area Network) tagged Ethernet frames are supported. Interworking with other Layer 2 technologies is also supported.
- Apipes: Emulates a point-to-point ATM (Asynchronous Transfer Mode) service. Several subtypes are provided to support different ATM service types.
- Fpipes: Emulates point-to-point Frame Relay circuit. Some features for interworking with ATM are also supported.
- Ipipes: Provides IP interworking capabilities between different Layer 2 technologies.
- Cpipes: Emulates a point-to-point time division multiplexing (TDM) circuit.