WO2018130299A1

WO2018130299A1 - Deleting duplicate messages

Info

Publication number: WO2018130299A1
Application number: PCT/EP2017/050689
Authority: WO
Inventors: Christopher Lowe
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2017-01-13
Filing date: 2017-01-13
Publication date: 2018-07-19

Abstract

A network device for relaying messages from a sender entity to a recipient entity, the network device being configured to: receive a message from the sender entity; analyse the message to determine whether the message is a duplicate of any of multiple messages already received from the sender entity for relaying to the recipient entity; and if the message is determined to be a duplicate of any of the multiple messages, supress it from being relayed to the recipient entity.

Description

DELETING DUPLICATE MESSAGES

BACKGROUND This invention relates to a method of deduplicating messages sent to an entity such as a terminal or user equipment device to reduce network and/or device load.

In many signalling applications, messages may be sent from a source such as an application server via a network to a user equipment ("UE") device. The protocol being used may provide for acknowledgement by the recipient. An example of such a protocol is Constrained Application Protocol (CoAP). When an acknowledgement is not received, for example if the UE device is asleep and the message cannot be delivered, it is possible that the source will re-send messages to the device. This results in the problem that there may be a set of duplicate messages waiting to be sent to the device. These messages can be queued at an intermediate entity such as a base station or a core network. When the UE device wakes up, unnecessary network load may be used in delivering the duplicate messages.

Some user equipment devices may deduplicate messages after they have been received. However, this means that the device battery and network resource are depleted in receiving the message multiple times. It would be desirable to reduce network load in handling messages to devices that may be unavailable for periods of time.

SUMMARY OF THE INVENTION According to one aspect of the invention there is provided a network device for relaying messages from a sender entity to a recipient entity, the network device being configured to: receive a message from the sender entity; analyse the message to determine whether the message is a duplicate of any of multiple messages already received from the sender entity for relaying to the recipient entity; and if the message is determined to be a duplicate of any of the multiple messages, supress it from being relayed to the recipient entity.

According to a second aspect of the invention there is provided a method for deduplicating messages sent from a sender entity to a recipient entity at a network device, wherein the network device is configured to: receive a message from the sender entity; analyse the message to determine whether the message is a duplicate of any of multiple messages already received from the sender entity for relaying to the recipient entity; and if the message is determined to be a duplicate of any of the multiple messages, supress it from being relayed to the recipient entity.

The network device may be a wireless base station. Performing the above-mentioned actions at a wireless base station can be a convenient way to reduce load on a wireless link between such a base station and a UE device.

The network device may be a core network entity. Performing the above-mentioned actions at a core network can be a convenient way to reduce load on a wireless link between such a core network and a UE device.

Messages from the sender entity may be sent according to a protocol that provides for acknowledgement by the recipient entity. That may allow one or more entities in the system to understand when a message has been received, and otherwise to retransmit the message. One example of a suitable protocol is Constrained Application Protocol (CoAP), including any protocol derived therefrom.

The device may be configured to perform the said analysis by: forming a first digest of at least a portion of a first message received from the sender entity; storing the first digest; forming a second digest of at least a portion of a second message received from the sender entity subsequently to the first message; and determining the second message to be a duplicate of the first message if the second digest is equal to the first digest. This can avoid the need to compare entire messages. Each message may comprise a payload and the step of analysing the message may comprise determining a message to be a duplicate if a portion of the message including the payload of the message is identical to the corresponding portion of a previously received message from the sender entity to the recipient entity. This can allow a message to be treated as a duplicate when its traffic data but potentially not some or all of its other data matches corresponding data of a previous message. Each message may include a sequence number field indicating the sequence number of the respective message, and the said portion of the message excludes the sequence number field. Each message may include a sender identity field indicating the identity of a sender of the respective message, and the said portion of the message includes the sender identity field. Each message may include a recipient identity field indicating the identity of a recipient of the respective message, and the said portion of the message includes the recipient identity field. The device may be configured to: store a queue of messages received from the sender entity for relaying to the recipient entity; and delete messages from the queue once they have been relayed to the recipient entity; the said multiple messages being those messages currently stored in the queue. In this way, duplicates of already-delivered messages can be redelivered.

BRIEF DESCRIPTION OF THE FIGURES

The present invention will now be described by way of example with reference to the accompanying drawings.

In the drawings:

Figure 1 shows a communication network for sending messages from a server to a user equipment device.

Figure 2 illustrates the deduplication of messages sent from a server to a user equipment device.

Figure 3 illustrates the architecture of a system in which messages can be deduplicated.

DETAILED DESCRIPTION OF THE INVENTION

The system to be described below may be used in a communications network, as illustrated in Figure 1.

A server 1 is connected, via a network 2 such as the internet, to a core network 3. The core network is wirelessly connected to a base station 4, which comprises a wireless transceiver 5, a processor 6 and a memory 7, with two parts for storing code and messages. A wireless transceiver 8 in the base station communicates with a user equipment device 9 via wireless transceiver 10. The user equipment device also comprises a processor 1 1 , a memory 12 with two parts for storing code and messages, and a user interface 13 for presenting information or for sensing environmental data. The user interface 13 may comprise a mechanism for communicating or interacting with the device's environment or user, for example a display, touch screen, or one or more transducers.

The server 1 sends a message to the core network 3 via the network 2. The message includes a destination address. Based on that destination address, which is the address of the UE to which the message is intended to be delivered, the core network routes the message to a suitable base station 4. At the base station, the message is sent on to the user equipment device 9. The message is sent over a wireless link from wireless transceiver 8 in the base station to a wireless transceiver 10 in the device. If the UE device 9 is awake, it receives and processes the message and sends an acknowledgement message back to the base station indicating that the message has been received by the device. The base station and the core network can then forward that message to the server. The server may then treat the message as having been successfully delivered. Alternatively, if an acknowledgement is not received at the server within a predetermined time of the original message having been sent by the server, the server may treat the message as undelivered and may attempt to resend the message to the UE device 9. As indicated above, if the reason for the non-acknowledgement is that the base station is unable to communicate with the UE device, this can result in duplicate messages being queues at the base station for sending to the UE device. In the description below, deduplication will be described as being performed at the base station. Alternatively, the analogous steps may be performed elsewhere, for example in a core network.

In the present system, the base station performs an analysis of messages it receives for forwarding to UE devices that are attached to it. The analysis is intended to determine whether each received message is a duplicate of a set of some or all messages previously sent to the user equipment device. If the message is determined to be a duplicate, the duplicate message is not sent to the user equipment device. In one example, the analysis may be intended to determine whether the message is a duplicate of all messages that (a) either (i) have been sent by the base station to the UE device or (ii) are queued for sending by the base station to the UE device and (b) the base station has not received acknowledgement for from the UE device.

As shown in Figure 2, a first message is sent at 14 from the server 1 to the base station 4 via the network 2 and core network 3 at time t1 . At 15 the base station checks whether the message is a duplicate (as will be described further below). Assuming it is not a duplicate the base station stores a record of the message in its local memory and then forwards at 16 the first message to the user equipment device 9 at time t2. At time t2, the user device is asleep, therefore no acknowledgement is sent back to the base station. Having been stored at 15 the first message remains queued at the base station with no acknowledgement having been received. Since no acknowledgement of the first message will be received at the server, in due course the first message is resent by the server at 17 at time t3. When the resent message reaches the base station, the base station checks whether this message is a duplicate at step 18. In this case the resent message is a duplicate of the first message. Therefore, the base station does not send this message on to the user equipment device. The original first message remains queued at the base station.

Suppose the server then sends at 19 a second, different message at time t4. The base station analyses the second message at step 20 and determines that this message is not a duplicate and so stores a record of it and then in step 21 sends the second message on to the user equipment device at time t5. The device is still asleep at time t5.

The base station may attempt to page the UE and retransmit when a link is available. This paging activity is not shown in Figure 2. In due course, at time t6, the UE device 9 wakes up and receives the retransmitted first and second messages which have been queued at the base station. Acknowledgements of the first and second messages are then sent to the base station at 22 and 23 respectively. Once these acknowledgements are received, the first and second messages may be deleted from the queue at the base station at 24 and acknowledgements for the first and second messages are sent to the server at 25 and 26 respectively. Duplicate messages received from the server and intended for delivery to a UE may be deleted at the base station, or not queued at the base station, once it is determined that they are a duplicate.

The network 2 may be a wide or narrow band network. It may be an internet of things network. User equipment device 9 may be configured to enter a low power (sleep) mode in which it is inhibited from receiving some or all messages from the base station.

The messages may be sent from the base station to the UE according to Constrained Application Protocol (CoAP) or a similar protocol. The protocol may incorporate a mechanism to retransmit datagrams (messages) when no acknowledgement has been received for them when a predetermined time has elapsed after sending.

In order to determine whether a newly received message is to be considered as a duplicate of a previous message, and therefore not forwarded, the base station compares some or all of the content of the newly received message with the corresponding content of some or all previous messages from the same source to the same destination. The comparison may be made directly on a bit-by-bit basis. Alternatively, the comparison may be made by comparing a digest (e.g. a hash) of the newly received message with digests of the previously received messages. Those digests can be stored at the base station. At the base station, a first hash or digest of at least a portion of the first message received from the sender entity may be taken and stored. A second hash or digest of at least a portion of the second message received from the sender entity subsequently to the first message may be taken. The second message may be determined to be a duplicate of the first message if the second hash is equal to the first hash. The portions of the messages over which a bit-by-bit comparison or a digest-based comparison are performed may, for example, be any of: (i) the entire messages, (ii) only the payloads of the messages, (iii) the payloads plus a portion of any control information (headers) in the messages. For example, the comparison may exclude certain control information such as sequence numbers, but may include other control information such as source and/or destination addresses. The set of messages against which the comparison of a newly received message is performed may (i) include all messages previously received by the base station or (ii) exclude message for which the base station has already received an acknowledgement from the recipient. The comparison process may be restricted to downlink messages.

The deduplication process may involve some knowledge of the underlying protocols. This may enable the base station to better establish whether a message is a duplicate.

The deduplication of messages at the base station, before transmission to the user equipment device, can result in reduced message transmission and therefore increased cell capacity and longer battery life on the user equipment device. It may also mean that simpler user equipment devices may be used.

Messages in a queue at the base station which have not been acknowledged by the user equipment device will be analysed to determine whether they are duplicates of messages already sent to the user equipment device. They may also be analysed to determine whether they are duplicates of other messages being held in the queue.

The retransmission period for a message, if not acknowledged, may be less than the time taken for the device to respond, i.e. the round-trip latency on the link between the base station and the UE. A potential benefit of deduplicating messages in the base station is that the base station can spot immediate retransmissions because the base station will know whether the latency for message delivery and acknowledgement is longer than retransmission period. For example, if the retransmission period is shorter than the latency of the user equipment device, a retransmission may be caused by the user equipment device being slow to respond, not because the message sent to the device was lost and therefore does not buffer for long periods of time.

Alternatively, instead of deduplication occurring at the base station, the deduplication may take place at the core network, before the messages are sent to the base station.

A potential benefit of deduplicating in the core network is that it may be more suitable for long- term queued messages. This may be more efficient for storage and communication between the core network and base station.

The core network or the base station may determine that messages are retransmissions using deep packet inspection.

The messages may comprise a payload. Some messages may contain sequence numbers. Although the totality of a pair of messages may differ due to their having different sequence numbers, the messages may still be considered to be a duplicates of each other on the basis of a match between some or all of the remainder of the messages. Therefore, the analysis of the messages to identify duplicates may exclude the sequence numbers of messages.

Some messages may also contain sender or receiver identity fields as part of the payload. These identity fields will typically be required to be the same if the message is to be treated as a duplicate message.

Where messages are determined to be duplicates by taking a hash of the message and analysing the resulting hashes, the hash of the messages may exclude the sequence number.

If a portion of the message including the payload of the message is identical to the corresponding portion of a previously received message from the sender entity to the recipient entity, it may be considered to be a duplicate.

The entity performing deduplication stores a queue of messages received from the sender entity for relaying to the recipient entity. The device deletes messages from the queue once they have been relayed to the recipient entity; the said multiple messages being those messages currently stored in the queue. Optionally, and depending on the protocol being deduplicated, only the most recent message may be stored; previous versions of the message may be deleted. In this manner, acknowledgements from the UE may be for the most recent message only. The invention is described above for message sent according to the CoAP protocol. The protocol by which the messages are sent according to could be a different protocol.

The invention is described above in the case of a wireless link between the base station and the UE device. This technique could also be implemented for a non-wireless network.

An example of an architecture of the system described above is shown in Figure 3. An application server 27 sends a message to network equipment 28 according to advanced message queueing protocol (AMQP). The network equipment sends this message on to the core network according to an internet protocol (IP). The core network comprises a serving gateway (S-GW) or packet data gateway (P-GW) 29 and a mobility management entity (MME) 30. The message is relayed between the S-GW/P-GW 29 and the MME 30, and from the MME 30 the message is relayed to the base station 31 . The message is sent from the base station to the UE module 32 according to a radio control link (RCL) protocol. The UE module decodes the message through a series of layers and presents it to an application 33 running on the module. As described above, the message can be deduplicated either at the base station or at the core network, as indicated at 34 and 35 respectively.

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

Claims

1 . A network device for relaying messages from a sender entity to a recipient entity, the network device being configured to:

receive a message from the sender entity;

analyse the message to determine whether the message is a duplicate of any of multiple messages already received from the sender entity for relaying to the recipient entity; and

if the message is determined to be a duplicate of any of the multiple messages, supress it from being relayed to the recipient entity.

2. The network device of claim 1 , wherein the network device is a wireless base station.

3. The network device of claim 1 , wherein the network device is a core network entity.

4. The network device of any preceding claim, wherein messages from the sender entity are sent according to a protocol that provides for acknowledgement by the recipient entity.

5. The network device of claim 4, wherein the protocol is Constrained Application Protocol (CoAP).

6. The network device of any preceding claim, wherein the device is configured to perform the said analysis by:

forming a first digest of at least a portion of a first message received from the sender entity;

storing the first digest;

forming a second digest of at least a portion of a second message received from the sender entity subsequently to the first message; and

determining the second message to be a duplicate of the first message if the second digest is equal to the first digest.

7. The network device of any preceding claim, wherein each message comprises a payload and the step of analysing the message comprises determining a message to be a duplicate if a portion of the message including the payload of the message is identical to the corresponding portion of a previously received message from the sender entity to the recipient entity.

8. The network device of claim 7, wherein each message includes a sequence number field indicating the sequence number of the respective message, and the said portion of the message excludes the sequence number field.

9. The network device of claim 7 or 8, wherein each message includes a sender identity field indicating the identity of a sender of the respective message, and the said portion of the message includes the sender identity field.

10. The network device of any of claims 7 to 9, wherein each message includes a recipient identity field indicating the identity of a recipient of the respective message, and the said portion of the message includes the recipient identity field.

1 1 . The network device of any preceding claim, wherein the device is configured to:

store a queue of messages received from the sender entity for relaying to the recipient entity; and

delete messages from the queue once they have been relayed to the recipient entity; the said multiple messages being those messages currently stored in the queue.

12. A method for deduplicating messages sent from a sender entity to a recipient entity at a network device, wherein the network device is configured to:

receive a message from the sender entity;

13. The method of claim 12, wherein the network device is a wireless base station.

14. The method of claim 12, wherein the network device is a core network entity.

15. The method of any of claims 12 to 14, wherein messages from the sender entity are sent according to a protocol that provides for acknowledgement by the recipient entity.

16. The method of claim 15, wherein the protocol is Constrained Application Protocol (CoAP).

17. The method of any of claims 12 to 16, wherein the device is configured to perform the said analysis by:

storing the first digest;

18. The method of any of claims 12 to 17, wherein each message comprises a payload and the step of analysing the message comprises determining a message to be a duplicate if a portion of the message including the payload of the message is identical to the corresponding portion of a previously received message from the sender entity to the recipient entity.

19. The method of claim 18, wherein each message includes a sequence number field indicating the sequence number of the respective message, and the said portion of the message excludes the sequence number field.

20. The method of claim 18 or 19, wherein each message includes a sender identity field indicating the identity of a sender of the respective message, and the said portion of the message includes the sender identity field.

21 . The method of any of claims 18 to 20, wherein each message includes a recipient identity field indicating the identity of a recipient of the respective message, and the said portion of the message includes the recipient identity field.

22. The method of any of claims 12 to 21 , wherein the network device is configured to: store a queue of messages received from the sender entity for relaying to the recipient entity; and