Editing Leased line (section)

===Site to site data connectivity===
Terminating a leased line with two routers can extend network capabilities across sites. Leased lines were first used in the 1970s by enterprise with proprietary protocols such as IBM [[System Network Architecture]] and Digital Equipment DECnet, and with [[TCP/IP]] in University and Research networks before the Internet became widely available. Note that other [[Network Layer|Layer 3]] protocols were used such as Novell IPX on enterprise networks until TCP/IP became ubiquitous in the 2000s. Today, point to point data circuits are typically provisioned as either [[Time-Division Multiplexing|TDM]], Ethernet, or Layer 3 MPLS.