9.3 Off-network SDS

24.2823GPPMission Critical Data (MCData) signalling controlProtocol specificationRelease 18TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

9.3.1 General

9.3.1.1 Message transport to a MCData Client

In order to transmit an off-network SDS message or SDS notification to an MCData user, the MCData client:

1) shall send the MONP MCData message transported in a MONP MCDATA MESSAGE CARRIER message, specified in 3GPP TS 24.379 [10], as a UDP message to the local IP address of the MCData user, on UDP port 8809 (as specified in TS 24.379 [10]), with an IP time-to-live set to 255; and

2) shall treat UDP messages received on the port 8809 as received MONP MCDATA MESSAGE CARRIER messages.

NOTE: An MCData client that supports IPv6 shall listen to the IPv6 addresses.

9.3.1.2 Message transport to a MCData Group

In order to transmit an off-network SDS message, an SDS notification or any one of the emergency alert messages mentioned in clause 16.3 to an MCData group, the MCData client:

1) shall send the MONP MCData message transported in a MONP MCDATA MESSAGE CARRIER message, specified in 3GPP TS 24.379 [10], as a UDP message to the multicast IP address of the MCData group, on UDP port 8809, with an IP time-to-live set to 255; and

2) shall treat UDP messages received on the multicast IP address of the MCData group and on port 8809 as received MONP MCDATA MESSAGE CARRIER messages, with the IP address treated as mentioned in "/<x>/<x>/OffNetwork/MCPTTGroupParameter/<x>/IPMulticastAddress" leaf node within the group configuration specified in 3GPP TS 24.483 [42].

The MONP MCDATA MESSAGE CARRIER message is the entire payload of the UDP message.

9.3.2 Standalone SDS using signalling control plane

9.3.2.1 General

9.3.2.2 Sending SDS message

Upon receiving an indication to send an SDS message, the MCData client:

1) if the request to send the SDS message is for a MCData group, shall check if the value of "/<x>/<x>/Common/MCData/AllowedSDS" leaf node, present in the group configuration as specified in 3GPP TS 24.483 [42], is set to "false". It the value is set to "false", shall reject the request to send the SDS message and not continue with the remaining procedures in this clause;

2) if:

a) a one-to-one SDS message is to be sent then, shall store the MCData user ID of the intended recipient as the target MCData user ID; or

b) a group SDS message is to be sent then, shall store the MCData group ID as the target MCData group ID;

3) may set the stored SDS disposition request type as:

a) "DELIVERY", if only delivery disposition is requested;

b) "READ", if only read disposition is requested; or

c) "DELIVERY AND READ", if both delivery and read dispositions are requested;

4) if an existing conversation is indicated then, shall store the conversation identifier of the indicated conversation as SDS conversation ID. Otherwise, shall generate an UUID as described in IETF RFC 4122 [14] and store SDS conversation ID;

5) shall generate an UUID as described in IETF RFC 4122 [14] and store as the SDS message ID;

6) if indicated that the SDS message is in reply to another SDS message then, shall store the message identifier of the indicated message as SDS reply ID;

7) if indicated that the target recipient of the SDS message is an application then, shall store the application ID of the indicated application as the SDS application ID or as the SDS extended application ID;

8) shall store the received payload as the SDS payload;

9) shall store the received payload type as the SDS payload type;

10) shall store the current UTC time as the SDS transmission time;

11) shall generate a SDS OFF-NETWORK MESSAGE message as specified in clause 15.1.7. In the SDS OFF-NETWORK MESSAGE message, the MCData client:

a) shall set the Sender MCData user ID IE to its own MCData user ID;

b) if:

i) a one-to-one SDS message is to be sent then shall set the Recipient MCData user ID IE to the stored target MCData user ID as specified in clause 15.2.15; or

ii) a group SDS message is to be sent then, shall set the MCData group ID IE to the stored target MCData group ID as specified in clause 15.2.14;

c) may set the SDS disposition request type IE to the stored the SDS disposition request type as specified in clause 15.2.3;

d) shall set the Conversation ID IE to the stored conversation ID as specified in clause 15.2.9;

e) shall set the Message ID IE to the stored SDS message ID as specified in clause 15.2.10;

f) shall set the Date and time IE to the stored SDS transmission time as specified in clause 15.2.8;

g) may include the InReplyTo message ID IE set to the stored SDS reply ID as specified in clause 15.2.11;

h) may include:

i) the Application ID IE set to the stored SDS application ID as specified in clause 15.2.7; or

ii) the Extended application ID IE set to the stored SDS extended application ID as specified in clause 15.2.24;

i) if end-to-end security is required for a one-to-one communication and the security context does not exist or if the existing security context has expired, shall include the Security parameters and Payload IE with security parameters as described in 3GPP TS 33.180 [26];

j) if

i) end-to-end security is not required for a one-to-one communication, or

ii) sending the SDS OFF-NETWORK MESSAGE message to a MCData group;

may include the Payload IE as specified in clause 15.2.13 with:

i) the Payload content type to the stored SDS payload type; and

ii) the Payload data set to the stored SDS payload;

12) if:

a) a one-to-one SDS message is to be sent then, shall send the SDS OFF-NETWORK MESSAGE message as specified in clause 9.3.1.1; or

b) a group SDS message is to be sent then, shall send the SDS OFF-NETWORK MESSAGE message as specified in clause 9.3.1.2;

13) shall initialise the counter CFS1 (SDS retransmission) with the value set to 1; and

14) shall start timer TFS1 (SDS retransmission).

9.3.2.3 Retransmitting SDS message

Upon expiry of timer TFS1 (SDS retransmission), the MCData client:

1) shall generate a SDS OFF-NETWORK MESSAGE message as specified in clause 15.1.7. In the SDS OFF-NETWORK MESSAGE message, the MCData client:

a) shall set the Sender MCData user ID IE to its own MCData user ID;

b) if:

i) a one-to-one SDS message is to be sent then, shall set the Recipient MCData user ID IE to the stored target MCData user ID; or

ii) a group SDS message is to be sent then, shall set the MCData group ID IE to the stored target MCData group ID;

c) may set the SDS disposition request type IE to the stored the SDS disposition request type as specified in clause 15.2.3;

d) shall set the Conversation ID IE to the stored conversation ID as specified in clause 15.2.9;

e) shall set the Message ID IE to the stored SDS message ID as specified in clause 15.2.10;

f) shall set the Date and time IE to the stored the SDS transmission time as specified in clause 15.2.8;

g) may include the InReplyTo message ID IE set to the stored SDS reply ID as specified in clause 15.2.11;

h) may include:

i) the Application ID IE set to the stored SDS application ID as specified in clause 15.2.7; or

ii) the Extended application ID IE set to the stored SDS extended application ID as specified in clause 15.2.24;

i) if end-to-end security is required for a one-to-one communication and the security context does not exist or if the existing security context has expired, shall include the Security parameters IE with security parameters as described in 3GPP TS 33.180 [26]; and

j) if:

i) end-to-end security is not required for a one-to-one communication, or

ii) sending the SDS OFF-NETWORK MESSAGE message to a MCData group;

may include the Payload IE as specified in clause 15.2.13 with:

i) the Payload content type to the stored SDS payload type; and

ii) the Payload data set to the stored SDS payload;

2) if:

a) a one-to-one SDS message was sent then, shall send the SDS OFF-NETWORK MESSAGE message as specified in clause 9.3.1.1; or

b) a group SDS message was sent then, shall send the SDS OFF-NETWORK MESSAGE message as specified in clause 9.3.1.2;

3) shall increment the counter CFS1(SDS retransmission) by 1; and

4) shall start timer TFS1 (SDS retransmission) if the associated counter CFS1 (SDS retransmission) has not reached its upper limit.

9.3.2.4 Receiving SDS message

Upon receiving an SDS OFF-NETWORK MESSAGE message with a SDS disposition request type IE, the MCData client:

1) shall store the value of Sender MCData user ID IE as the stored notification target MCData user ID;

2) shall store the value of Conversation ID IE as the stored conversation ID;

3) shall store the value of Message ID IE as the stored SDS message ID;

4) shall store the current UTC time as the stored SDS notification time;

5) if present, shall store the value of Application ID IE as the stored SDS application ID;

6) if present, shall store the value of the Extended application ID IE as the stored SDS extended application ID;

7) if present, shall store the value of MCData group ID IE to the stored target MCData group ID; and

8) if the SDS disposition request type IE is set to:

a) "DELIVERY" then, shall send a SDS OFF-NETWORK NOTIFICATION message as described in clause 12.3.2;

b) "READ" then, shall send a SDS OFF-NETWORK NOTIFICATION message as described in clause 12.3.3; or

c) "DELIVERY AND READ" then, shall start timer TFS3 (delivery and read).

NOTE: Duplicate messages (re-transmissions) that are received by the MCData client should not be processed again.

9.3.2.5 SDS Read while TFS3 (delivery and read) is running

Upon receiving a display indication before timer TFS3 (delivery and read) expires, the MCData client:

1) shall generate and send a SDS OFF-NETWORK NOTIFICATION message as described in clause 12.3.4.

9.3.2.6 Timer TFS3 (delivery and read) expires

Upon expiry of timer TFS3 (delivery and read), the MCData client:

1) shall generate and send a SDS OFF-NETWORK NOTIFICATION message as described in clause 12.3.2; and

2) upon receiving a display indication, shall generate and send a SDS OFF-NETWORK NOTIFICATION message as described in clause 12.3.3.