On the establishment of an access VPN in broadband access networks

Many corporate networks use the Internet as a cost-effective substitute for expensive leased lines and long-distance telephone calls, for allowing their users to have on-demand connectivity into their intranets through ad hoc tunnels, a concept known as access VPN. Establishing an access VPN in a broadband access network is very often a difficult networking challenge that requires several tunnels to be established between the various involved entities. This is especially the case in an open broadband access network where the association between a host and its ISP is not known to the network in advance. This article discusses several schemes for establishing an access VPN in a broadband access network, and explains the need for the various tunnels in each scheme.