Module codec 

NGAP (3GPP TS 38.413) PDU structure, the IEs of the procedures NetGet speaks, and message builders — shared by the AMF (server) and the gNB (client).

What is decoded and what is skipped

An NGAP PDU is a CHOICE of initiating / successful / unsuccessful message, each carrying a procedure code, a criticality and an open type holding a ProtocolIE-Container: a list of (id, criticality, open type) fields. decode_pdu walks that outer structure for every procedure, so any NGAP message can be framed, named and have its IE ids reported. The IE values are decoded only for the procedures listed in procedure_name’s implemented set: NG Setup, Initial UE Message, Downlink/Uplink NAS Transport, Error Indication, NG Reset and UE Context Release. An IE NetGet does not decode stays as its raw octets and is surfaced by id — the open-type framing is exactly what lets a receiver do that honestly.

Every value is checked against its ASN.1 constraint on the way in and on the way out, so an action cannot put a 33-bit gNB ID or an eleven-digit MCC on the wire.

Bounds

MAX_PDU_LEN bounds the PDU, MAX_IES the IE count per container, MAX_NAS_PDU_LEN the NAS-PDU, and every SEQUENCE OF is bounded by its own 38.413 constraint and by MAX_LIST_ITEMS in total per decode, so the structure handed to the model is bounded however the peer nests its lists. No decoder here recurses.

Re-exports

pub use aper::AperError as WireError;

Structs

Budget

Counts list elements across one PDU so nested lists cannot multiply into an unbounded event.

Cause

An NGAP Cause: a group and an index in that group’s root (or, when extended, its extension list).

EncodeError

An encode refusal: what the action asked for cannot be put on the wire.

Ie

One ProtocolIE-Field, its value still an encoded open type.

InitialUe

The UE-associated fields of an Initial UE Message.

NasTransport

The fields of a Downlink or Uplink NAS Transport.

Pdu

One NGAP PDU with its IEs framed but not interpreted.

Plmn

A PLMN identity, three TBCD octets (TS 38.413 section 9.3.3.5, TS 24.008 figure 10.5.13).

ProtocolError

A PDU NetGet refuses, with the NGAP Cause that tells the peer why. The detail is for the log only; nothing in it is put on the wire.

Enums

CauseGroup

Criticality

PduKind

Constants

CHOICE_EXTENSIONS

Marker for the choice-Extensions index of a CHOICE with alternatives alternatives.

IE_AMF_NAME

IE_AMF_SET_ID

IE_AMF_UE_NGAP_ID

IE_CAUSE

IE_CRITICALITY_DIAGNOSTICS

IE_DEFAULT_PAGING_DRX

IE_FIVE_G_S_TMSI

IE_GLOBAL_RAN_NODE_ID

IE_NAS_PDU

IE_PLMN_SUPPORT_LIST

IE_RAN_NODE_NAME

IE_RAN_UE_NGAP_ID

IE_RELATIVE_AMF_CAPACITY

IE_RESET_TYPE

IE_RRC_ESTABLISHMENT_CAUSE

IE_SERVED_GUAMI_LIST

IE_SUPPORTED_TA_LIST

IE_TIME_TO_WAIT

IE_UE_ASSOCIATED_LOGICAL_NG_CONNECTION_LIST

IE_UE_CONTEXT_REQUEST

IE_UE_NGAP_IDS

IE_USER_LOCATION_INFORMATION

MAX_AMF_UE_NGAP_ID

MAX_IES

IEs accepted in one ProtocolIE-Container. The constraint allows 65535; the largest message in NetGet’s subset carries about ten.

MAX_LIST_ITEMS

SEQUENCE OF elements decoded per PDU, summed across every list in it.

MAX_NAS_PDU_LEN

Largest NAS-PDU accepted or written. A 5GMM message NetGet handles is under a hundred octets; 8 KiB leaves room for any capability container a UE might add without approaching the APER fragmentation threshold.

MAX_PDU_LEN

Largest NGAP PDU accepted or written. NGAP itself has no length field; this is the bound on one SCTP message (or one lab-transport frame).

MAX_RAN_UE_NGAP_ID

MISC_CONTROL_PROCESSING_OVERLOAD

MISC_HARDWARE_FAILURE

MISC_OM_INTERVENTION

MISC_UNKNOWN_PLMN

MISC_UNSPECIFIED

NAS_NORMAL_RELEASE

NAS_UNSPECIFIED

PPID

SCTP Payload Protocol Identifier for NGAP (TS 38.412 section 7).

PROC_AMF_CONFIGURATION_UPDATE

PROC_DOWNLINK_NAS_TRANSPORT

PROC_ERROR_INDICATION

PROC_INITIAL_UE_MESSAGE

PROC_NG_RESET

PROC_NG_SETUP

PROC_RAN_CONFIGURATION_UPDATE

PROC_UE_CONTEXT_RELEASE

PROC_UPLINK_NAS_TRANSPORT

PROTOCOL_ABSTRACT_SYNTAX_ERROR_REJECT

PROTOCOL_MESSAGE_NOT_COMPATIBLE_WITH_RECEIVER_STATE

PROTOCOL_SEMANTIC_ERROR

PROTOCOL_TRANSFER_SYNTAX_ERROR

PROTOCOL_UNSPECIFIED

RADIO_INCONSISTENT_REMOTE_UE_NGAP_ID

RADIO_UNKNOWN_LOCAL_UE_NGAP_ID

SCTP_PORT

SCTP port the AMF listens on (TS 38.412 section 7, IANA).

Functions

amf_ue_ngap_id_ie

cause_ie

connection_list_ie

decode_amf_ue_ngap_id

decode_cause

decode_connection_list_ie

decode_global_ran_node_id

GlobalRANNodeID — gNB form decoded; ng-eNB and N3IWF forms named only.

decode_name

decode_nas_pdu

decode_pdu

Decode the outer structure of one NGAP PDU.

decode_plmn_support_list

decode_ran_ue_ngap_id

decode_relative_amf_capacity

decode_reset_type

ResetType: None is reset-all, Some(items) the partial form.

decode_served_guami_list

decode_supported_ta_list

decode_time_to_wait

decode_ue_ngap_ids

UE-NGAP-IDs: (amf_ue_ngap_id, Some(ran_ue_ngap_id)) for the pair form.

decode_user_location

UserLocationInformation: NR decoded fully, E-UTRA decoded, N3IWF named.

downlink_nas_transport

encode_pdu

Encode one NGAP PDU.

error_indication

global_gnb_id_ie

ie_name

Name of an IE id NetGet decodes, for events. Others are reported by number.

initial_ue_message

is_ue_associated

True when the PDU is UE-associated signalling — it carries an AMF or RAN UE NGAP ID — which TS 38.412 section 7 sends on a non-zero SCTP stream. Non-UE-associated signalling (NG Setup, NG Reset, a UE-less Error Indication) uses stream 0.

json_opt_u64

json_u64

name_ie

nas_pdu_ie

ng_reset

ng_reset_acknowledge

NG Reset Acknowledge; for a partial reset the list of connections reset is echoed (38.413 section 8.7.4.2.1).

ng_setup_failure

ng_setup_request

ng_setup_response

NG Setup Response from the model’s fields.

paging_drx_ie

parse_cause_message

NG Setup Failure, or any message carrying an optional Cause and Time to Wait.

parse_initial_ue_message

Initial UE Message (TS 38.413 section 9.2.5.1).

parse_nas_transport

Downlink (9.2.5.2) or Uplink (9.2.5.3) NAS Transport.

parse_ng_setup_request

NG Setup Request, decoded for the model (TS 38.413 section 9.2.6.1).

parse_ng_setup_response

NG Setup Response, decoded for the gNB’s model (TS 38.413 section 9.2.6.2).

peek

The procedure code and kind of an encoded PDU, read without decoding the rest.

plmn_support_list_ie

[{"plmn": {...}, "slices": [{"sst": 1, "sd": "010203"}]}]

procedure_name

Name of a procedure code, for logs and events. None for a code NetGet has no name for.

ran_ue_ngap_id_ie

relative_amf_capacity_ie

reset_type_ie

served_guami_list_ie

[{"plmn": {...}, "amf_region_id": 2, "amf_set_id": 1, "amf_pointer": 0}]

summarize

Every IE id of an encoded PDU, for logs; None when it does not decode.

supported_ta_list_ie

[{"tac": 1, "broadcast_plmns": [{"plmn": {...}, "slices": [{"sst": 1}]}]}]

time_to_wait_ie

ue_context_release_command

ue_context_release_complete

ue_ngap_ids_ie

uplink_nas_transport

user_location_nr_ie

NR user location: {"cgi": {"plmn", "cell_id"}, "tai": {"plmn", "tac"}}.

Type Aliases

CodecResult

ConnectionItem

One UE-associatedLogicalNG-connectionItem: either id may be absent.

EncodeResult