5.7 Descriptors

29.3343GPPIMS Application Level Gateway (IMS-ALG) - IMS Access Gateway (IMS-AGW)Iq InterfaceRelease 17Stage 3TS

5.7.1 TerminationState Descriptor

Table 5.7.1.1: ServiceState property

ServiceState property used:

Yes (InService/OutofService) NOTE 1, NOTE 2

NOTE 1: This is restricted to the ROOT termination (for MGW audit).

NOTE 2: Ephemeral H.248 Terminations have a ServiceState property according to ITU-T Recommendation H.248.1 [10], but explicit usage of the TerminationState Descriptor ServiceState property is not required by this Profile. ServiceState changes can still occur, however, and can be indicated in ServiceChange Commands (i.e. this means that the value of the ServiceState property may be implicitly changed by ServiceChange procedures).

Table 5.7.1.2: EventBufferControl property

EventBufferControl property used:

No

Table 5.7.1.3: Group semantics property

Group semantics property used:

Yes

NOTE: This is restricted to ephemeral H.248 Terminations used for WebRTC service support. The property is used in conjunction with the media grouping package, see clause 5.14.3.23.

Table 5.7.1.4: SDPCapNeg Extensions property

SDPCapNeg Extensions property used:

Yes

NOTE: The property is used in conjunction with the Enhanced Revised Offer/Answer SDP Support package, see clause 5.14.3.x1.

5.7.2 Stream Descriptor

5.7.2.0 General

Table 5.7.2.1: Stream descriptors

Maximum number of streams per termination type

IP

Unspecified (NOTE 1, NOTE 2)

NOTE 1: At least one stream for each media component (e.g. video+audio = 2 streams). If only one stream is applicable, then the IMS-ALG may omit the Stream Descriptor and the IMS-AGW shall assume that StreamID = 1.

NOTE 2: An IP termination for WebRTC may carry additional H.248 (de-)aggregation streams besides the legacy H.248 component streams.

Table 5.7.2.2: Stream configuration

Stream configuration:

ALL configurations are allowed.

IP terminations for WebRTC may apply H.248 stream grouping principles, which leads to relationships of associated H.248 streams within such stream group configurations.

5.7.2.1 LocalControl Descriptor

Table 5.7.2.1.1: LocalControl Descriptor and Reserve properties

Termination Type

Stream Type

ReserveGroup used:

No

NA

NA

ReserveValue used:

Yes

IP

Audio, Video (NOTE 1, NOTE 2)

NOTE 1: The value of the H.248 Stream Type is given here by the SDP "m=" line element media type (in contrast to the SDP "m=" line element transport protocol in Table 5.7.2.1.2). Usage of ReserveValue implies thus media type aware Local and Remote Descriptors.

NOTE 2: Not used (at this profile version (see clause 5.1 for the version number)) for TCP transport (IETF RFC 793 [51]) and media types:
a) "Message" (for MSRP (IETF RFC 4975 [18]) and
b) "Application" (for BFCP (IETF RFC 4582 [52]) and ROI FECC (IETF RFC 4573 [62]))
because the application control will not use them in context ReserveValue.

Table 5.7.2.1.2: Allowed Stream Modes

Termination Type

Stream Type

Allowed StreamMode Values

IP

RTP/AVP

SendOnly, RecvOnly, SendRecv, Inactive

RTP/SAVP

SendOnly, RecvOnly, SendRecv, Inactive

RTP/AVPF

SendOnly, RecvOnly, SendRecv, Inactive

RTP/SAVPF

SendOnly, RecvOnly, SendRecv, Inactive

TCP (NOTE 1)

SendRecv, Inactive

TCP/MSRP (NOTE 1)

SendRecv, Inactive

TCP/TLS (NOTE 1)

SendOnly, RecvOnly, SendRecv, Inactive

TCP/TLS/MSRP (NOTE 1, NOTE 2)

SendOnly, RecvOnly, SendRecv, Inactive

UDPTL

SendRecv, Inactive

UDP

SendOnly, RecvOnly, SendRecv, Inactive

UDP/DTLS

SendOnly, RecvOnly, SendRecv, Inactive

UDP/DTLS/SCTP (NOTE 3)

SendOnly, RecvOnly, SendRecv, Inactive

NOTE 1: The H.248 StreamMode does not affect protocol control information at the bearer interface. See clause 7.1.7.1.1 in ITU-T Recommendation H.248.1 [10] and:
a) TCP: ITU-T Recommendation H.248.89 [47], clause 8.6.4.1, Table "Impact of StreamMode on TCP bearer traffic at external MG interface"
b) TLS: ITU-T Recommendation H.248.90 [48], clause 8.6.4.1, Table "Impact of StreamMode on TLS bearer traffic at external MG interface".

NOTE 2: Conditional support, dependent on support of application-aware interworking.

NOTE 3: Conditional support, dependent on WebRTC service with data application(s).

NOTE 4: Conditional support, dependent on WebRTC service and DTLS-based SRTP key exchange for audio or video.

Table 5.7.2.1.3: LocalControl Descriptor and other properties

Termination Type

Stream Type

Stream Aggregation used:

No

NA

NA

Stream De-aggregation used:

Yes

IP for WebRTC

WebRTC Data (NOTE)

NOTE: Conditional, dependent on WebRTC calls with multiple data components.

5.7.3 Events descriptor

Table 5.7.3.1: Events Descriptor

Events settable on termination types and stream types:

Yes

If yes

EventID

Termination Type

Stream Type

Cause (g/cause, 0x0001/0x0001) – See clause 5.14.3.1

ALL except ROOT

ANY

Inactivity Timeout (it/ito,
0x0045/0x0001) – See clause 5.14.3.6

only ROOT

Not applicable

MG_Overload

(ocp/mg_overload, 0x0051/0x0001) – See clause 5.14.3.8

only ROOT

Not applicable

Termination Heartbeat (hangterm/thb, 0x0098/0x0001) – See clause 5.14.3.9

ALL except ROOT

ANY

MGCon (chp/mgcon, 0x0029/0x0001) – See clause 5.14.3.10

only ROOT

Not Applicable

Available Realms Changed (ipra/arc, 0x00e0/0x0001) – See clause 5.14.3.11

only ROOT

Not Applicable

IP Flow Stop Detection (adid/ipstop, 0x009c/0x0001) – See clause 5.14.3.14

ALL except ROOT

Any

ECN Failure (ecnrous/fail, 0x010b/0x0001) see clause 5.14.3.15

IP

RTP based

ICE New Peer Reflexive Candidate (ostuncc/nprc, 0x00c3/0x0002) – see clause 5.14.3.17

IP

Any, only applicable for full ICE

ICE Connectivity Check Result (ostuncc/ccr, 0x00c3/0x0001) – see clause 5.14.3.17

IP

Any, only applicable for full ICE

TCP connection state change ("BNC change")
(tcpbcc/BNCChange, 0x0115/0x0001) see clause 5.14.3.18

IP

TCP based

TLS session state change ("BNC change")
(tlsbsc/BNCChange, 0x0117/0x0001) see clause 5.14.3.19

IP

TLS or DTLS based

STUN Consent Request Failure (stnconfres/constate,

0x0120/0x0002) see clause 5.14.3.22

IP

TLS or DTLS based, only applicable for full ICE

SCTP connection state change (sctpbcc /BNCChange, 0x0121/0x0001) see clause 5.14.3.24

IP

SCTP based

Detect outgoing SCTP stream reset
(sctpreset/detreset, 0x0122/0x0001) see clause 5.14.3.25

IP

SCTP based

Outgoing SCTP stream reset result
(sctpreset/result, 0x0122/0x0002) see clause 5.14.3.25

IP

SCTP based

Table 5.7.3.2: Event Buffer Control

EventBuffer Control used:

No

Table 5.7.3.3: Keep active

KeepActive used on events:

No

Table 5.7.3.4: Embedded events and signals

Embedded events in an Events Descriptor:

No

Embedded signals in an Events Descriptor:

No

Table 5.7.3.5: Regulated Embedded events

Regulated Embedded events are triggered on:

None

Table 5.7.3.6: ResetEventsDescriptor

ResetEventsDescriptor used with events:

None

Table 5.7.3.7: Notification Behaviour

NotifyImmediate:

ALL Events

NotifyRegulated:

None

NeverNotify:

None

5.7.4 EventBuffer descriptor

Table 5.7.4.1: Event Buffer Descriptor

EventBuffer Descriptor used:

No

If yes

EventIDs

–

5.7.5 Signals descriptor

Table 5.7.5.1: Signals Descriptor

The setting of signals is dependant on termination or streams types:

No

NOTE – "No" means that all signals can be played on any termination or stream. If "Yes", any signal not listed below may be played on any termination or stream, except Signals on ROOT termination shall not be supported.

If yes

SignalID

Termination Type

Stream Type / ID

Latching (ipnapt/latch, 0x0099/0x0001)

ALL except ROOT

Any

Send Additional Connectivity Check (ostuncc/sacc, 0x00c3/0x0002)

IP

Any, only applicable for full ICE

Send Connectivity Check (ostuncc/scc, 0x00c3/0x0001)

IP

Any, only applicable for full ICE

Establish BNC
(tcpbcc/EstBNC, 0x0115/0x0001) see clause 5.14.3.18

IP

TCP based

Release BNC
(tcpbcc/RelBNC, 0x0115/0x0002) see clause 5.14.3.18

IP

TCP based

Establish BNC
(tlsbsc/EstBNC, 0x0117/0x0001) see clause 5.14.3.19

IP

TLS or DTLS based

Release BNC
(tlsbsc/RelBNC, 0x0117/0x0002) see clause 5.14.3.19

IP

TLS or DTLS based

Consent Test (stnconfres/contst, 0x0120/0x0001) see clause 5.14.3.22

IP

TLS or DTLS based

Establish BNC (sctpbcc/EstBNC, 0x0121/0x0001) see clause 5.14.3.24

IP

SCTP based

Release BNC (sctpbcc/RelBNC, 0x0121/0x0002) see clause 5.14.3.24

IP

SCTP based

Initiate Outgoing SCTP Stream Reset (sctpreset/initreset, 0x0122/0x0001) see clause 5.14.3.25

IP

SCTP based

Outgoing SCTP Stream Reset Response
(sctpreset/resetresp, 0x0122/0x0002) see clause 5.14.3.25

IP

SCTP based

Table 5.7.5.2: Signal Lists

Signals Lists supported:

No

If yes

Termination Type Supporting Lists:

–

Stream Type Supporting lists:

–

Maximum number of signals to a signal list:

–

Intersignal delay parameter supported:

–

Table 5.7.5.3: Overriding Signal type and duration

Signal type and duration supported:

No

If yes

SignalID

Type or duration override

–

–

Table 5.7.5.4: Signal Direction

Signal Direction supported:

No

Table 5.7.5.5: Notify completion

NotifyCompletion supported:

No

If yes

SignalID

Type of completion supported

–

–

Table 5.7.5.6: RequestID Parameter

RequestID Parameter supported:

No

Table 5.7.5.7: Signals played simultaneously

Signals played simultaneously:

No

If yes

SignalIDs that can be played simultaneously:

Table 5.7.5.8: Keep active

KeepActive used on signals:

No

5.7.6 DigitMap descriptor

Table 5.7.6.1: DigitMap Descriptor

DigitMaps supported:

No

If yes

DigitMap Name

Structure

Timers

–

–

–

5.7.7 Statistics descriptor

Table 5.7.7.1: Statistics Descriptor support

Statistics supported on:

–

Table 5.7.7.2: Statistics Report on Subtract

Statistics reported on Subtract:

No

If yes

StatisticIDs reported:

–

5.7.8 ObservedEvents descriptor

Table 5.7.8.1: ObservedEvents Descriptor

Event detection time supported:

No

5.7.9 Topology descriptor

Table 5.7.9.1: Topology Descriptor

Allowed triples:

(T1, T2, isolate)

(T1, T2, bothway)

NOTE: The Topology Descriptor shall be supported by the MGW and MGC for handover only, when PS-to-CS access transfer is supported.

5.7.10 Error descriptor

Table 5.7.10.1: Error Codes Sent by IMS-ALG

Supported H.248.8 Error Codes:

#400 "Syntax error in message"

#401 "Protocol Error"

#402 "Unauthorized"

#403 "Syntax Error in TransactionRequest"

#406 "Version Not Supported"

#410 "Incorrect identifier"

#411 "The transaction refers to an unknown ContextID"

#413 "Number of transactions in message exceeds maximum"

#421 "Unknown action or illegal combination of actions"

#422 "Syntax Error in Action"

#430 "Unknown TerminationID"

#431 "No TerminationID matched a wildcard"

#442 "Syntax Error in Command"

#443 "Unsupported or Unknown Command"

#444 "Unsupported or Unknown Descriptor"

#445 "Unsupported or Unknown property"

#446 "Unsupported or Unknown Parameter"

#447 "Descriptor not legal in this command"

#448 "Descriptor appears twice in a command"

#449 "Unsupported parameter or property value"

#450 "No such property in this package

#451 "No such event in this package"

#454 "No such parameter value in this package"

#455 "Property illegal in this Descriptor"

#456 "Property appears twice in this Descriptor"

#457 "Missing parameter in signal or event"

#458 "Unexpected Event/RequestID"

#501 "Not Implemented"

#502 "Not ready"

#505 "Transaction Request Received before a

ServiceChange Reply has been received"

#506 "Number of TransactionPendings Exceeded"

#533 "Response exceeds maximum transport PDU size"

Supported Error Codes defined in packages:

All error codes defined in supported packages are supported.

NOTE: The error codes listed need not be supplied by the IMS-ALG to differentiate each and every error described by them. The IMS-AGW shall be able to receive the error codes listed.

Table 5.7.10.2: Error Codes Sent by IMS-AGW:

Supported H.248.8 Error Codes:

#400 "Syntax error in message"

#401 "Protocol Error"

#402 "Unauthorized"

#403 "Syntax Error in TransactionRequest"

#406 "Version Not Supported"

#410 "Incorrect identifier"

#411 "The transaction refers to an unknown ContextID"

#412 "No ContextIDs available"

#413 "Number of transactions in message exceeds maximum"

#421 "Unknown action or illegal combination of actions"

#422 "Syntax Error in Action"

#430 "Unknown TerminationID"

#431 "No TerminationID matched a wildcard"

#432 "Out of TerminationIDs or No TerminationID available"

#433 "TerminationID is already in a Context"

#434 "Max number of Terminations in a Context exceeded"

#435 "Termination ID is not in specified Context"

#440 "Unsupported or unknown Package"

#441 "Missing Remote or Local Descriptor"

#442 "Syntax Error in Command"

#443 "Unsupported or Unknown Command"

#444 "Unsupported or Unknown Descriptor"

#445 "Unsupported or Unknown property"

#446 "Unsupported or Unknown Parameter"

#447 "Descriptor not legal in this command"

#448 "Descriptor appears twice in a command"

#449 "Unsupported parameter or property value"

#450 "No such property in this package

#451 "No such event in this package"

#452 "No such signal in this package"

#454 "No such parameter value in this package"

#455 "Property illegal in this Descriptor"

#456 "Property appears twice in this Descriptor"

#457 "Missing parameter in signal or event"

#471 "Implied Add for Multiplex failure"

#488 "Incorrect stream endpoint interlinkage"

#489 "Invalid aggregation and/or deaggregation"

#500 "Internal software Failure in MG or MGC"

#501 "Not Implemented"

#502 "Not ready"

#505 "Transaction Request Received before a

ServiceChange Reply has been received"

#506 "Number of TransactionPendings Exceeded"

#510 "Insufficient resources"

#511 "Temporarily Busy"

#512 "Media Gateway unequipped to detect requested Event"

#513 "Media Gateway unequipped to generate

requested Signals"

#515 "Unsupported Media Type"

#517 "Unsupported or invalid mode"

#522 "Functionality Requested in Topology Triple Not Supported"

#526 "Insufficient bandwidth"

#529 "Internal hardware failure in MG"

#530 "Temporary Network failure

#531 "Permanent Network failure"

#532 "Audited Property, Statistic, Event or Signal does

not exist"

#533 "Response exceeds maximum transport PDU size"

#534 "Illegal write of read only property"

#542 "Command is not allowed on this termination"

Supported Error Codes defined in packages:

All error codes defined in supported packages need to be supported.

NOTE: The error codes listed need not be supplied by the IMS-AGW to differentiate each and every error described by them. The IMS-ALG shall be able to receive the error codes listed.