5 Functional entities

24.5453GPPLocation Management - Service Enabler Architecture Layer for Verticals (SEAL)Protocol specificationRelease 17TS

5.1 SEAL location management client (SLM-C)

The SLM-C functional entity acts as the application client for location management related transactions. To be compliant with the HTTP procedures in the present document the SLM-C:

shall support the role of XCAP client as specified in IETF RFC 4825 [9];

shall support the role of XDMC as specified in OMA OMA-TS-XDM_Core-V2_1 [12];

shall support the location management procedures in clause 6.2;

shall support the off-network location management procedure in clause 6.3; and

shall support HTTP client and HTTP server functionalities as specified in IETF RFC 7230 [20].

To be compliant with the CoAP procedures in the present document the SLM-C:

– shall support the role of CoAP client as specified in IETF RFC 7252 [21];

– shall support FETCH method of CoAP as specified in IETF RFC 8132 [24];

– shall support the capability to observe resources as specified in IETF RFC 7641 [23];

– shall support the block-wise transfer as specified in IETF RFC 7959 [22];

– may support the robust block transfer as specified in IETF draft draft-ietf-core-new-block-14 [27];

– should support CoAP over TCP and Websocket as specified in IETF RFC 8323 [25];

– shall support CBOR encoding as specified in IETF RFC 8949 [26]; and

– shall support the procedures in clause 6.2.

NOTE 1: The security mechanism to be supported for the CoAP procedures is described in 3GPP TS 24.547 [6].

NOTE 2: Support for TCP for the CoAP procedures is required if the client connects over the network which blocks or impedes the use of UDP, e.g. when NATs are present in the communication path.

NOTE 3: The CoAP protocol supports mechanism for reliable message exchange over UDP. Use of TCP can also be beneficial if reliable transport is required for other reasons, e.g. better observability of resources. Usage of CoAP over TCP is an implementation choice.

NOTE 4: Support for the robust block transfer mechanism for the CoAP procedures is beneficial in environments where packet loss is highly asymmetrical and where performance optimization of block transfers is required.

5.2 SEAL location management server (SLM-S)

The SLM-S is a functional entity used to provide location management supported within the vertical application layer. To be compliant with the HTTP procedures in the present document the SLM-S:

shall support the role of XCAP server as specified in IETF RFC 4825 [9];

shall support the role of XDMS as specified in OMA OMA-TS-XDM_Core-V2_1 [12];

shall support the location management procedures in clause 6.2; and

shall support HTTP client and HTTP server functionalities as specified in IETF RFC 7230 [20].

To be compliant with the CoAP procedures in the present document the SLM-C:

– shall support the role of CoAP server as specified in IETF RFC 7252 [21];

– shall support FETCH method of CoAP as specified in IETF RFC 8132 [24];

– shall support the capability to observer resources as specified in IETF RFC 7641 [23];

– shall support the block-wise transfer as specified in IETF RFC 7959 [22];

– shall support the robust block transfer as specified in IETF draft draft-ietf-core-new-block-14 [27];

– shall support CoAP over TCP and Websocket as specified in IETF RFC 8323 [25];

– shall support CBOR encoding as specified in IETF RFC 8949 [26]; and

– shall support the procedures in clause 6.2.

NOTE: The security mechanism to be supported for the CoAP procedures is described in 3GPP TS 24.547 [6].