Multi-path wireless communication

Patent metadata

Field	Value
Publication number	US-2019149455-A1
Application number	US-201716097996-A
Country	US
Kind code	A1
Filing date	May 5, 2017
Priority date	May 9, 2016
Publication date	May 16, 2019
Grant date	—

Abstract

A client and a server communicate over multiple wireless access paths each using a different wireless network. A method performed at the server comprises receiving at the server a signal from the client via one of multiple wireless access paths, the signal comprising a transport layer portion including a transport layer identifier, the transport layer identifier providing an indication of a wireless access path, a network layer portion, and a data portion, determining from the transport layer identifier, a destination of at least a subset of the signals from the wireless access path indicated by the transport layer identifier, and routing the signal to the destination. If a flow is diverted to travel via a different route, then there must be some mechanism to ensure that the signal arrives at its intended destination. Preferably, a Multi-path Transport Control Protocol (MPTCP) is used as the transport layer protocol. MPTCP binds one or multiple TCP subflows into one logical connection between a content data server and a user client application. In the client device, a network policy module specifies what physical paths can be accessed and whether they are used symmetrically for ACK delivery (marker [a]). Signals that are diverted such that they are sent between these devices on a different access path to that originally envisaged, need to be rerouted within the receiving device such that they arrive at the correct “socket” and can be processed by the appropriate receiver. To implement the “WiFi uplink over LTE uplink” policy, a client pre-routing function (marker [b]) modifies the source/destination IP addresses of the uplink TCP packets prior to passing them to the network so that the network can then transparently carry out the desired traffic routing. On the server side, a server pre-routing function (marker [c]) modifies the destination IP addresses of all TCP ACKs such that the IP layer subsequently ensures delivery to the correct TCP state machines of the server. The server establishes the “TCP ACK-to-TCP socket” mapping during TCP connection setup and maintains its state by monitoring TCP traffic (marker [d]).

First claim

1 . A method performed at a server of routing a signal received from a client, said client and server being configured to communicate over multiple wireless access paths each using a different wireless network, the method comprising:
receiving at said server a signal from said client via one of said wireless access paths, said signal comprising a transport layer portion including a transport layer identifier, said transport layer identifier providing an indication of an originally envisaged wireless access path prior to any re-routing, a network layer portion providing an indication of a wireless access path taken, and a data portion; determining a destination of at least a subset of said signals from said wireless access path indicated by said transport layer identifier; and routing said signal to said destination.

2 . A method according to claim 1 , comprising analysing at least a subset of said signals and where said transport layer identifier indicates a different wireless access path to said network layer portion, amending said network layer parameters to correspond to said wireless access path indicated by said transport layer identifier.

3 . A method according to claim 1 , wherein said data portion comprises response data generated by said client in response to receipt of a data signal transmitted by said server, said transport layer identifier associated with said response signal identifying said wireless access path that said corresponding data signal was transmitted on.

4 . A method according to claim 1 , comprising an initial step of analysing signals transmitted when establishing a session connection between said client and said server and determining a wireless access path used for said session connection and a transport layer identifier associated with said wireless access path.

5 . A method according to claim 4 , comprising monitoring evolution of said transport layer identifier associated with said session connection.

6 . A method according to claim 1 , comprising receiving a network policy indicating particular types of signals that may be re-routed via other wireless access paths, said subset of signals being said signals of said indicated type.

7 . A method according to claim 1 , wherein said determining step comprises determining whether said transport layer portion of said signal has an expected size and where a size of said portions is larger than said expected size, discarding a first part of said transport layer portion and analysing a remaining part.

8 . A method according to claim 1 , wherein said determining is performed at a processor arranged either before or after said network layer.

9 . A method performed at a client of routing a signal to a server via one of multiple wireless access paths, each using a different access network, the method comprising: generating a signal comprising a transport layer portion including a transport layer identifier, a network layer portion, and a data portion;
said transport layer identifier and said network layer portion providing an indication of a wireless access path; determining whether said signal is to be transmitted via a wireless access path that is different to that indicated by said network layer portion and said transport layer identifier; and when so, amending said network layer portion to indicate said new wireless access path and maintaining said transport layer identifier such that said original wireless access path is derivable therefrom.

10 . A method according to claim 9 , comprising on establishing a session connection between said client and said server, providing said session connection with a transport layer identifier that uniquely identifies said session connection, associating said transport layer identifier with signals transmitted over said session connection.

11 . A method according to claim 10 , wherein said providing a unique transport layer identifier comprises generating a transport layer identifier and providing said transport layer identifier with an offset.

12 . A method according to claim 9 , comprising receiving a network policy indicative of signals to be re-routed over a wireless access path that is different to that indicated by a network layer associated with said signals, said step of determining being performed in dependence upon said received network policy.

13 . A method according to claim 9 , comprising amending said transport layer portion by appending said generated transport layer portion to a spoof
transport layer portion suitable for an analogous signal transmitted over said new wireless access path.

14 . A computer program which when executed by a processor is operable to control said processor to perform a method according to claim 1 .

15 . A routing device for routing a signal received at a server from a client via one of multiple wireless access paths, each using a different access network;
said signal comprising a transport layer portion including a transport layer identifier, said transport layer identifier providing an indication of an originally envisaged wireless access path prior to any re-routing, a network layer portion providing an indication of a wireless access path taken, and a data portion; said routing device comprising an analyser configured to determine a destination of at least a subset of said signals from said wireless access path indicated by said transport layer identifier and routing circuitry configured to route said signal to said destination.

Assignees

• Kucera Stepan
• Buddhikot Milind
• Alcatel Lucent

Inventors

• Kucera Stepan
• Buddhikot Milind

Classifications

• H04W40/02

  Communication route or path selection, e.g. power-based or shortest path routing · CPC title

• H04L45/24 Primary

  Multipath · CPC title

• H04L69/163

  In-band adaptation of TCP data exchange; In-band control procedures · CPC title

• H04L67/141

  Setup of application sessions (admission control or resource allocation in data switching networks H04L47/70) · CPC title

• H04W80/06

  Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless {(transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16)} · CPC title