4_제너 VoIP Protocol Introduction(MGCP)

8/13/2019 4_ VoIP Protocol Introduction(MGCP)

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VoIP Protocol Introduction(MGCP)

PKT-SP-EC-MGCP-I10-040402


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CONTENTS

1 SCOPE2 INTROUDUCTION

3 MGCI

4 MGCP


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SCOPE

Describe Media Gateway Control Protocol(MGCP) for Packet Cable Embedded Client

Refer to as the Packet Cable NCS( Network-Based Call S ignaling) Protocol Describe MGCI(Media Gateway Control Interface) and MGCP Based on the MGCP

MGCP 0.1(Draft)

MGCP 1.0(RFC 2705)IETF

MEGACO(MGCP 2.0)

ITU-T H.GCP

MGCP 1.0 bis(draft)

PacketCable

NCS MGCP 1.0


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INTRODUCTION

Describe an abstract application programming interface (MGCI) and a corresponding protocol(MGCP) for controlling media gateways from external call control elements called media gateway

controllers or Call Agents

Call Control ArchitectureCall Agent : Call Control ElementGateway : Conversion audio signals and data packets

Connection ModelBasic constructs are endpoints and connections

Endpoints : A Terminal, Gateway, MCU

Connection : Point-To-Point(the one is the originator, the other is the terminator)

Point-To-Multipoint


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MGCI

MGCI Functions Connection Control

Endpoint ControlAuditingStatus ReportingUse Same System Model and Same Naming Conventions

Model and Naming Conventions

Endpoint Names- local-endpoint-name@domain-name

Call Names- Call ID- Created by Call Agent

Connection names

- Connection ID- Created by Gateway

MGCI-Model and Naming Conventions


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MGCI

Model and Naming Conventions Digit Maps

The Formal syntax of Digit MapDigit ::= 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 Timer ::= T | t -- matches the detection of timerLetter ::= Digit | Timer | # | * | A | a | B | b | C | c | D | d Range ::= X | x -- matches any digit

| [ Letters ] -- matches any of the specified lettersLetters ::= Subrange | Subrange LettersSubrange ::= Letter -- matches the specified letter

| Digit - Digit -- matches any digit between first and last

Position ::= Letter | RangeStringElement ::= Position -- matches an occurrence of the position| Position . -- matches an arbitrary number of occurrence

-- of the position, including 0String ::= StringElement | StringElement StringStringList ::= String | String | StringList DigitMap ::= String | ( StringList )

Above Dial Plan can be described in the following Digit Map(0T | 00T | [1-7]xxx | 8xxxxxxx | #xxxxxxx | *xx | 91xxxxxxxxxxxxx | 9011x.T)

Possible Dialing Numbers(Dial Plan)0 Local operator *xx Star services00 Long Distance Operator 91xxxxxxxxx Long Distance Numberxxxx Local Exchange Number 9011 + up to 15 digits International number8xxxxxxx Shortcut to local number at other corporate sites



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Model and Naming Conventions Events and Signals

SDP USEProvide the gateways with the description of connection parameters(IP Address, UDP Port, RTP Profiles..)

CallAgent

EmbeddedClient

Notify Events(L/hd)

Request Signals(L/dl)

L/hd : hook-off in line package for an analog access lineL/dl : dial-tone in line package for an analog access line


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MGCI-Gateway Control Functions

Gateway Control FunctionsDescribe the commands of the MGCP

Notification Request(RQNT)Used to request the gateway to send a notification upon the occurrence ofSpecified events in an endpoint

NotificationRequest(EndpointId[, NotifiedEntity][, RequestedEvents], RequestIdentifier[, DigitMap][, SignalRequests][, QuarantineHandling][, DetectEvents])

ex) RequestedEvents(R) : L/hu, L/ft, D/[0- 9*#] RequestIdentifier(X) : Used to correlate this requestDigitMap(D) : X.TSignalRequests(S) : rt, rg, bz..QuarantineHandling(Q) : Optional ParameterDetectEvents(T) : Optional Parameter


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Notifications(NTFY)

Send NTFY CMD by the gateway When an Observed event is to be notified

Notify(EndpointId [, NotifiedEntity], RequestIdentifier, ObservedEvents)

ex) ObservedEvents(O) : Events that were requested in the RequestedEventsParameter, O:l/hu

Create Connection(CRCX)Used to a create connection

CreateConnection(CallId, EndpointId[, NotifiedEntity][, LocalConnectionOptions], Mode[, RemoteConnectionDescriptor]

ex) Call ID(C) : Identify the call (or session) to which this connection belongs.LocalConnectionOptons(L) : Encoding Method, Packetization Period,

Echo Cancel, Silence Suppression..L:nt:IN, a:PCMA, e:on, s:off

RemoteConnectionDescriptor:SDP



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ModifyConnection(MDCX)

Used to modify the connection

ModifyConnection(CallId , EndpointId, ConnectionId[, NotifiedEntity][, LocalConnectionOptions][, Mode][, RemoteConnectionDescriptor][, RequestedEvents][, RequestIdentifier][, DigitMap][, SignalRequests]

ex) Mode(M) : Indicates the mode of operation for this side of the connectionRecvOlny, Send/recv..



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DeleteConnection(DLCX)

Used to terminate a connection

DeleteConnection(CallId , EndpointId, ConnectionId[, NotifiedEntity][, RequestedEvents][, RequestIdentifier][, DigitMap][, SignalRequests][, QuarantineHandling][, DetectEvents])

The gateway returns a list of parameters that describe the status of the connection.ex) Connection Parameters(P)

250 TransactionID OKP:PS=2, OS=0, PR=306, OR=7344, PL=0, JI=5, LA=0



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Auditing(AUEP, AUCX)

AuditEndPoint(AUEP): Used by the Call Agent to determine the status of an endpointAuditConnection(AUCX): Used by the Call Agent to obtain information about a connection

AuditEndPoint(EndpointId[, RequestedInfo] |{ [, SpecificEndPointID][, MaxEndPointIDs] })

AuditConnection(EndpointId , ConnectionId[, RequestedInfo])

ex) RequestedInfo(F) :AUEP TID EndpointIdF: ES, A, I ES : Event Status

A : Capabilities200 TID OK I : Connection IDES:I/huA: a:PCMU;G723;G729, s:off



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Restart in Progress(RSIP)

Used by the gateway to signal that an endpoint, or a group of endpoints, istaken out of service or is being placed back in service.

RestartInProgress(EndpointId , RestartMethod[, RestartDelay][, ReasonCode])

ex) Restart Method(RM) :Graceful : That the specified endpoint(s) will be taken out of service after

The specified restart delay(RD) Cancel-graceful : Indicates that a gateway is canceling a previously issued

"graceful restart method for the same endpoints Forced : Indicates that the specified endpoints are taken out of service abruptlyRestart : Indicates that service will be restored on the endpoints after the

Specified restart delay Disconnected : Indicates that the endpoint has become disconnected

Established connections are not affected



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All MGCP commands receive a response. The response carries a return codethat indicates the status of the command.

. value 000 indicates a response acknowledgement24,

. values between 100 and 199 indicate a provisional response,

. values between 200 and 299 indicate a successful completion,

. values between 400 and 499 indicate a transient error,

. values between 500 and 599 indicate a permanent error.

Return Code Definitions100 The transaction is currently being executed. An actual completion message

will follow later.200 The requested transaction was executed normally.~401 The phone is already off hook.~500 The transaction could not be executed because the endpoint is unknown.501 The transaction could not be executed because the endpoint is not ready .~521 Endpoint redirected to another Call Agent.534 Codec negotiation failure.

MGCI-Return Codes and Error Codes


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MGCI-Use of Local Connection Options and connection Descriptors

CRCX(Local Connection Option)

200 OKSDP:Local Connection Descriptor


CRCX(Local Connection Option)SDP:Remote Connection Descriptor


MDCX(Local Connection Option)

SDP:Remote Connection Descriptor

Codec andpacketization period selection

CRCX(L: a:G723)RCD(m=4 18 0 8)

200 OKLCD(m=4)

EX)


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MGCP- General Description

General Description Command

Ex)CRCX 2005 aaln/[email protected] MGCP 1.0 NCS 1.0

C: 0L: p:20, a:PCMU;PCMA;G.723.1-5.3;G.723;G.729A, s:on, e:onM: recvonlyX: 3R: huS: rt

TID Transaction ID) : Value between 1 and 999999999Correlate commands and responses

Head Body

cmd tid Endpoint Name version parameters SDPs


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MGCP- General Description

General Description Response

EX)200 2005 OK

I: 686B

v=0o=- 26731 2005 IN IP4 218.232.96.222s=-c=IN IP4 218.232.96.222t=0 0m=audio 3456 RTP/AVP 0 8 4 18a=recvonlya=ptime:20

Head Body

tid comment parameters SDPsReCode


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Command Direction Description

AUCX (MGC MG) Retrieve the parameters attached to the connection

AUEP (MGC MG) Find out the status of a given endpoint

EPCF (MGC MG) Specify the encoding of signals that will be received bythe endpoint

CRCX (MGC MG) Create Connection between two endpoints

DLCX (MGC MG) Terminate connection

MDFY (MGC MG) Modify the characteristics of gateways view of aconnection

RQNT (MGC MG) Request the gateway to send NTFY upon occurrence ofspecified events in an endpoint

NTFY (MGC MG) Notification

RSIP (MGC MG) Signal to the MGC that an endpoint, or a group ofendpoint, is take in or out of service

MGCP- Command Header

Command Line


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Parameter Line RequestIdentifier(X)

Correlate a Notify command with the NotificationRequest that triggered it

Local Connection Options(L)Describe the operational parameters that the Call Agents instructs theGateway to use for a connection. These parameters are p, a, s, e etc.

RequestedEvents(R)Provides the list of events that have been requestedR: hu(N), hf(N) Notify on-hook, notify hook-flash.R: hu(N), [0-9#T](D) Notify on-hook, accumulate digits according to

Digitmap SignalRequests(S)

Provides the name of the signals that have been requestedS: ci(10/14/17/26, 555 1212, CableLabs) S : rgS : rt


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Parameter Line ObservedEvents(O)

Provide the list of events that have been observedO: 8,2,9,5,5,5,5,T 0:hf

RequestInfo(F)Contain a comma separated list of parameter codesF: ES,I,A

CallId(C) ,DigitMap(D)EX)CRCX 1120660 isup/1/1/[email protected] MGCP 1.0C: 22002a4L: nt:IN, a:G723, fx:t38, e:on, s:off

M: sendrecvD: ([0-9*#])X: 22002a4R: fxr/t38, D/[0-9*#](D)


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MGCP- Response Header Formats

Create ConnectionThe Response line is followed by a Connection-Id parameter witha successful

response(code 200). A LocalConnectionDescriptor is furthermore transmittedwith a positive response

Ex)200 1204 OKI: FDE234C8

v=0o=- 25678 753849 IN IP4 128.96.41.1s=-c=IN IP4 128.96.41.1t=0 0

m=audio 3456 RTP/AVP 96 97 0a=rtpmap:96 G726-32/8000a=rtpmap:97 telephone-event/8000a=mptime: 10 - 10


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ModifyConnectionThe response line is followed by a LocalConnectionDescriptor

Ex)200 1207 OKv=0o=- 25678 753849 IN IP4 128.96.41.1s=-

c=IN IP4 128.96.41.1m=audio 3456 RTP/AVP 0a=mptime: 20

DeleteConnectionThe response line may be followed by a Connection Parameters parameter line

Ex)250 1210 OKP: PS=1245, OS=62345, PR=780, OR=45123, PL=10, JI=27, LA=48


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NotificationRequest/NotifyNot include any additional response parameters

AuditEndpointThe response line may be followed by information for each of the parametersRequested each parameter will appear on a separate line.

Ex)

200 1200 OKA: a:PCMU; p:10, e:on, s:off, t:1, v:L,

AuditConnectionThe Response may be followed by information for each of the parameters requested

Ex)200 1203 OKC: A3C47F21456789F0P: PS=622, OS=31172, PR=390, OR=22561, PL=5, JI=29, LA=50,


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RestartInProgressThe response to a RestartInProgress may include the name of another Call Agent to

Contact, for Instance when the Call Agent redirects the endpoint to another CallAgent as in:

521 1204 RedirectN: [email protected]


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MGCP- Session Description Encoding

SDP Avdio Service UseProtocol Version(V=)

Origin(o=)Session Name(s=)Connection Data(c=)Media Announcements(m=)Attributes(a=)

Ex)v=0c=IN IP4 218.232.19.236m=audio 24830 RTP/AVP 4a=ptime:30a=cdsc : 1 image udpt I t38


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MGCP- Piggy-Backing

Separated by a line of text that contains a single dot

200 2005 OK.DLCX 1244 aaln/[email protected] MGCP 1.0 NCS 1.0C: A3C47F21456789F0I: FDE234C8

Used to guarantee in-order delivery of messagesUsed to Fate-Sharing of message delivery

k


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MGCP- Event Packages

Line PackagePackage Name : L

Used to identify events and signals for the line package for analog Access Line bz Busy Tone, dl Dial Tone, ft Fax Tone, hd Off Hook, hu On Hook,hf Flash Hook, ot Off Hook Warning Tone, rg Ringing, rt Ring Back Tone,sl Stutter Dial Tone, wt Call Waiting Tone

MGCP R id i l G R


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MGCP- Residential Gateway Restart

rsip 1001 *@TEST.0000 MGCP 1.0

RM:restartRD:0

200 1001 OK

AUEP 216 aaln/[email protected] MGCP 1.0F: ES,A,I

200 216 OKES:l/huA: a:PCMU;G726-32;G723; gc:0, s:off

RQNT 217 aaln/[email protected] MGCP 1.0S:X: 210000eQ: discardR: L/hd

200 217 OK

RMG Call Agent

Q ti ?


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Questions ?

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4_제너 VoIP Protocol Introduction(MGCP)