7 Transport layer
36.4583GPPEvolved Universal Terrestrial Radio Access Network (E-UTRAN)Release 17SLm interface signalling transportTS
SCTP (IETF RFC 4960 [5]) shall be supported as the transport layer of SLmAP signalling bearer. The Payload Protocol Identifier assigned by IANA to be used by SCTP for the application layer protocol SLmAP is TBD.
SCTP refers to the Stream Control Transmission Protocol developed by the Sigtran working group of the IETF for the purpose of transporting various signalling protocols over IP network.
There shall be only one SCTP association established between one E-SMLC and LMU pair.
The LMU shall establish the SCTP association. The SCTP Destination Port number value assigned by IANA to be used for SLmAP is TBD.
Within the SCTP association established between one E-SMLC and LMU pair:
– a single pair of stream identifiers shall be reserved for the sole use of SLmAP elementary procedures that utilize non UE-associated signalling.
– At least one pair of stream identifiers shall be reserved for the sole use of SLmAP elementary procedures that utilize UE-associated signalling. However, a few pairs (i.e. more than one) should be reserved.
– A single UE-associated signalling shall use one SCTP stream and the stream should not be changed during the communication of the UE-associated signalling.
Transport network redundancy may be achieved by SCTP multi-homing between two end-points, of which one or both is assigned with multiple IP addresses. SCTP end-points shall support a multi-homed remote SCTP end-point. For SCTP endpoint redundancy an INIT may be sent from E-SMLC, at any time for an already established SCTP association, which shall be handled as defined in IETF RFC 4960 [5] in subclause 5.2.
The SCTP congestion control may, using an implementation specific mechanism, initiate higher layer protocols to reduce the signalling traffic at the source and prioritise certain messages.
Annex A (informative):
Change History
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Change history |
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Date |
TSG # |
TSG Doc. |
CR |
Rev |
Subject/Comment |
New |
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2012-12 |
58 |
RP-121768 |
Approved in RAN#58 and put under change control |
11.0.0 |
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2014-09 |
Update to Rel-12 version (MCC) |
12.0.0 |
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2015-12 |
Update to Rel-13 version (MCC) |
13.0.0 |
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Change history |
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Date |
Meeting |
TDoc |
CR |
Rev |
Cat |
Subject/Comment |
New version |
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2017-03 |
SA#75 |
Promotion to Release 14 without technical change |
14.0.0 |
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2018-06 |
SA#80 |
– |
– |
– |
– |
Promotion to Release 15 without technical change |
15.0.0 |
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2020-07 |
SA#88-e |
– |
– |
– |
– |
Update to Rel-16 version (MCC) |
16.0.0 |
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2022-03 |
SA#95-e |
Promotion to Release 17 without technical change |
17.0.0 |
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