Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital data error correction
Reexamination Certificate
2000-05-26
2004-05-04
Ton, David (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital data error correction
C714S776000
Reexamination Certificate
active
06732314
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of telecommunications and more specifically to a method and apparatus for providing Layer Two Tunneling Protocol (L
2
TP) forward error correction.
2. Description of Related Art
Layer Two Tunneling Protocol (L
2
TP) is a mechanism that enables automatic tunneling between a dialup user and a private network. L
2
TP may also be used to establish a Virtual Private Network (VPN) between two distinct IP networks connected by a third public network, such as the Internet. Unlike IP-in-IP tunneling, L
2
TP offers a number of advantages. For example, L
2
TP can encapsulate an entire PPP session within an X/IP/UDP session, where X is a data-link protocol. L
2
TP also allows for negotiation of session parameters via a virtual control channel and provides sequence numbers and retransmission mechanisms for reliability, flow control, and congestion control. L
2
TP is also extensible via user-defined extension headers.
A current L
2
TP protocol is discussed and detailed in the document entitled “Layer Two Tunneling Protocol “L
2
TP””, Network Working Group, Request for Comments: 2661, August 1999 which is herein entirely incorporated by reference and to which the reader is directed to for further information.
Although there are advantages to using L
2
TP for tunneling between a remote user and a private network, L
2
TP has certain drawbacks. For example, L
2
TP does not allow for the use of error correction. For example, the current L
2
TP protocol does not allow for an established tunnel to include forward error correction. The protocol, therefore, does not allow either the remote user and/or the local network to enable forward error correction for an established tunnel. In addition, in instances where forward error correction is not required for the entire tunnel, the L
2
TP protocol does not allow for an established call or a plurality of calls within a tunnel to utilize forward error correction. Moreover, the L
2
TP protocol does not allow a routing device of a first private network, such as an Local Area Concentrator (LAC) router or Remote Access Concentrator (RAC), to establish forward error correction within an entire tunnel or just for a specific “session” or call. There is, therefore, a need for forward error correction where L
2
TP is used.
SUMMARY OF THE INVENTION
The present invention relates to a method of establishing an L
2
TP tunnel between a first IP network and a first private IP network. A routing device of the first IP network is coupled to a public network and a routing device of the first private IP network is coupled to the public network. An L
2
TP tunnel is initiated from either the routing device of the first IP network or the routing device of the private IP network. An IP address from an address space of the first private IP network is provided and the L
2
TP tunnel is maintained between the routing device of the first IP network and the routing device of the second private IP network. Data traffic is tunneled between the first and the second IP network over the public network via the L
2
TP tunnel. A control mechanism is utilized for providing L
2
TP tunnel traffic error correction.
In another aspect of the invention, an L
2
TP call is established between a first IP network and a first private IP network. A routing device of the first IP network and a routing device of the first private IP network is coupled to the public network. An L
2
TP call is initiated between the routing device of the first IP network and the routing device of the private IP network. The first IP network is provided with an IP address of the first private IP network. The L
2
TP call is maintained between the routing device of the first IP network and the routing device of the second private IP network. The L
2
TP call traffic is tunneled between the first and the second IP network over the public network. A control mechanism is utilized for providing L
2
TP call traffic error correction.
REFERENCES:
patent: 6081508 (2000-06-01), West et al.
patent: 6434149 (2002-08-01), Jackson et al.
patent: 6452915 (2002-09-01), Jorgensen
patent: 6473793 (2002-10-01), Dillon et al.
patent: 6480748 (2002-11-01), Gerszberg et al.
patent: 6484210 (2002-11-01), Adriano et al.
patent: 6519651 (2003-02-01), Dillon
Borella Michael S.
Mahler Jerry
Schuster Guido
Sidhu Ikhlaq S.
3Com Corporation
McDonnell & Boehnen Hulbert & Berghoff
Ton David
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