Network-based micro mobility in cellular networks using extended virtual private LAN service

Abstract

A new architecture provides network-based mobility in cellular networks that is built on Internet Protocol (IP) / Multiprotocol Label Switching (MPLS) technologies, such as Virtual Private Local Area Network (LAN) Service (VPLS), the Border Gateway Protocol (BGP) and BGP MPLS Layer 3 Virtual Private Networks (VPNs). The architecture consists of several building blocks that provide functionality for different aspects of cellular network mobility. One building block is network-based macro mobility in IP / MPLS networks. The macro mobility techniques described herein are built on extensions to a routing protocol such as BGP. Another building block relates to transferring subscriber context between network devices while preserving the IP address of the subscriber. The techniques described herein provide a subscriber context transfer mechanism for mobile subscriber management that is built on extensions to a routing protocol such as BGP. Another building block of the mobility architecture is network-based micro mobility based on VPLS.

Description

[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 143,993, filed Jan. 12, 2009, the entire content of which is incorporated by reference herein.TECHNICAL FIELD[0002]The invention relates to networks and, more particularly, to cellular networks.BACKGROUND[0003]A cellular network is a collection of cells that each includes at least one base station capable of transmitting and relaying signals to subscriber's mobile devices. A “cell” generally denotes a distinct area of a cellular network that utilizes a particular frequency or range of frequencies for transmission of data. A typical base station is a tower to which are affixed a number of antennas that transmit and receive the data over the particular frequency. Mobile devices, such as cellular or mobile phones, smart phones, camera phones, personal digital assistants (PDAs) and laptop computers, may initiate or otherwise transmit a signal at the designated frequency to the base station in order to initi...

AI Technical Summary

Benefits of technology

[0010]The Mobile MPLS architecture described herein consists of several building blocks that provide functionality for different aspects of cellular network mobility. One building block is network-based macro mobility in IP / MPLS networks. The macro mobility solution described herein is built on extensions to a routing protocol and VPNs. The techniques allow a routing protocol, such as the Border Gateway Protocol (BGP), to be extended in a manner that allows mobile subscriber VPN routes to be communicated between routing devices for providing network-based macro mobility. For example, BGP can be extended in a manner that allows reachability to a mobile subscriber to be announced along with a MPLS mobile VPN label. In this manner, the techniques allow for the advertisement of per-subscriber routing state and enable each member of the mobile VPN that imports this route to route traffic directly to the IP gateway device to which the mobile subscriber is connected, thereby bypassing the current anchor device of the mobile subscriber and avoiding triangular routing.

[0012]One of the challenges in building a macro mobility solution is the tradeoff between optimal routing and mobile subscriber state. Efficient routing of packets destined to and from mobile subscribers typically requires per subscriber routing state in the network. Solutions such as Mobile IPv4 or Proxy Mobile IP may reduce this state at the cost of inefficient routing (triangular routing). The solution described herein allows the service provider (SP) to select between a triangular routing mode and an optimal routing mode, giving the flexibility to provide either efficient routing (i.e., shortest path routing) or avoid per subscriber state. Moreover, the embodiments described herein that are provided by this solution allow an SP to make such a decision on a per subscriber basis.

[0018]The embodiments described herein can be integrated with various wireless access technologies, including WiMax and LTE. In addition, a subset of the embodiments can be integrated with 3G for IP data traffic. The embodiments described herein provide Micro Mobility in a WiMax network that uses IP / MPLS for mobile backhaul by re-using, with extensions as required, the IP / MPLS mechanisms. For example, micro mobility may be provided by using Virtual Private LAN Service (VPLS) in the backhaul network. This embodiment eliminates the need to run a new WiMax control protocol in the backhaul network for Micro Mobility. Moreover, the embodiment allows the same control plane mechanism to be used for wireline and mobile services. The embodiment also allows for the same control plane to be used for IPv4 and IPv6.

Problems solved by technology

As a result, routers and other network devices that do not support the extension may ignore the encoded mobile subscriber reachability information.

One of the challenges in building a macro mobility solution is the tradeoff between optimal routing and mobile subscriber state.

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