Networking layer extension

Abstract

A device, for example a ZigBee device, includes an 802.15.4 MAC layer 4 and a ZigBee networking layer 2. A switch layer 10 is provided, having an interface 12 imitating a MAC layer interface and a database 18. The switch layer 10 is able to parse commands from the ZigBee networking layer 2 and route them if appropriate to an alternative lower layer 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, embodiments will now be described, purely by way of example, with reference to the accompanying drawings, in which:

FIG. 1 illustrates a prior art ZigBee networking system;

FIG. 2 illustrates a system according to a first embodiment of the invention; and

FIG. 3 illustrates a further embodiment of the invention; and

FIG. 4 illustrates an application of the embodiment of FIG. 2.

Claims

1. A device including a multiplicity of logical layers, for networking to a plurality of destinations, comprising: a networking layer;a medium access control layer including a networking interface for interfacing with the networking layer; and an 802.15.4 interface for connecting to an 802.15.4 physical layer;characterised in that the medium access control layer further includes:at least one alternate interface for connecting to a respective alternate physical layer;a switch layer between the networking interface, the 802.15.4 interface and the at least one further lower interface capable of switching instructions and data received from and sent to the networking interface (i) through the 802.15.4 interface to the 802.15.4 physical layer (ii) through an alternate interface to the respective alternate physical layer, or (iii) through all of the alternate interfaces and the 802.15.4 interface;wherein the switch layer includes a database storing information about which lower layer connects to which destination; andthe switch layer is arranged to process a message received from the networking layer requiring transmission of a message to a specific destination, by:checking the database to determine whether the database contains information as to which interface connects to the specific destination and if the database contains the information as to which interface connects to the specific destination, by passing the command to the corresponding interface, and if the database does not contain information as to which interface connects the specific destination, by passing the command to all interfaces.

2. A device according to claim 1, wherein the switch layer is arranged, when passing a message received from a destination through one of the interfaces to the networking layer, to record in the database the address of the destination and a handle indicating which one of the interfaces was in communication with that destination.

3. A device according to claim 1, wherein the switch layer is arranged, when passing a message received from a destination through one of the interfaces to the networking layer, to record in the database the address of the destination, a handle indicating which one of the interfaces was in communication with that destination, and the time.

4. A device according to claim 1 wherein the device is a ZigBee device and the networking layer is a ZigBee networking layer.

5. A device according to claim 1 wherein at least one alternate interface is arranged to package 802.15.4 messages to the destination in a suitable message format for the corresponding physical layer so that they can be transmitted to the destination through the corresponding physical layer and unpackaged to be acted on as 802.15.4 messages at the destination.

6. A device according to claim 1 wherein at least one alternate interface is arranged to convert 802.15.4 messages to the destination to a suitable protocol for the corresponding physical layer.

7. A device according to claim 1 wherein the switch layer is arranged to process commands by: if the command received from the networking layer requires listening for a message, the switch layer passes the command to all lower layers, and when the switch layer receives a message from a particular destination from a particular lower layer, the switch layer updates the database to indicate that the particular destination is connected through that lower layer.

8. A method of operating a switch layer for serving a networking layer with communications links to a plurality of destinations linked by a plurality of physical layers including an 802.15.4 layer and at least one alternate layer through respective 802.15.4 and alternate interfaces, the switch layer including a database, the method including: maintaining communication with a networking layer;receiving messages from the networking layer;parsing the messages and determining which destination should receive the command; andpassing the command to the determined destination;wherein:if the command received from the networking layer requires transmission of a message to a specific destination, the switch layer checks the database to determine whether the database contains information as to which physical layer connects to the specific destination and if so passes the command to the corresponding lower layer, and if the database does not contain information as to which lower layer connects the specific destination the switch layer passes the command to all lower layers.

9. A method according to claim 8 further comprising, when passing a message received from a destination through one of the interfaces to the networking layer, recording in the database the address of the destination and a handle indicating which one of the interfaces was in communication with that destination.

10. A method according to claim 8 further comprising, when passing a message received from a destination through one of the interfaces to the networking layer, recording in the database the address of the destination, a handle indicating which one of the interfaces was in communication with that destination, and the time.

11. A method according to claim 8 wherein the networking layer is a ZigBee networking layer.

12. A method according to claim 8 further including packaging in an alternate interface 802.15.4 messages to a destination in a suitable message format for the corresponding physical layer so that they can be transmitted to the destination through the corresponding physical layer and unpackaged to be acted on as 802.15.4 messages at the destination.

13. A method according to claim 8 wherein if the command received from the networking layer requires listening for a message, the switch layer passes the command to all layers, and when the switch layer receives a message from a particular destination from a particular layer, the switch layer updates the database to indicate that the particular destination is connected through that layer.

14. A network comprising: at least one Zigbee device includinga networking layer;a medium access control layer including a networking interface for interfacing with the networking layer; and an 802.15.4 interface for connecting to an 802.15.4 physical layer;characterised in that the medium access control layer further includes:at least one alternate interface for connecting to a respective alternate physical layer;a switch layer between the networking interface, the 802.15.4 interface and the at least one further lower interface capable of switching instructions and data received from and sent to the networking interface (i) through the 802.15.4 interface to the 802.15.4 physical layer (ii) through an alternate interface to the respective alternate physical layer, or (iii) through all of the alternate interfaces and the 802.15.4 interface;wherein the switch layer includes a database storing information about which lower layer connects to which destination; andthe switch layer is arranged to process messages by:if a message received from the networking layer requires transmission of a message to a specific destination, checking the database to determine whether the database contains information as to which interface connects to the specific destination and if so passes the command to the corresponding interface, and if the database does not contain information as to which interface connects the specific destination the switch layer passes the command to all interfaces;the network further comprising at least one additional device connected through the alternate physical layer, the switching layer routing messages to and from the additional device so that the or each additional device appears to the network layer as a device on the ZigBee network.