MGCP_ MEGACO

8/12/2019 MGCP_ MEGACO

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Gatekeeper/SIP-Server

Gateways use H.323 or SIP

VoIP-PC VoIP-PC

GK/SIP-Server

VoIP-PC

MG

CPE

GK/SIP-Server

VoIP-PC

DSS1

MG

Private Branch Exchange

GK/SIP-Server

VoIP-PC

DSS1

MGPBX

Local Exchange


2/13

MG

Media Gateway

Controller

VoIP MediaGateway MGCP

or

MEGACO

VoIP MediaGateway

Gateways

that support MGCP orMEGACO

MG

SS7 Signaling SS7 Signaling

PCM30trunk line

PCM30trunk line

hiG 1000 / 1200


3/13

Functions of Gatewayswith SIP or H.323

MG

SignalingHandlingFunction

MediaGatewayFunction

GatewayControl

Function

SignalingHandlingFunction

Voice Info(TDM)

Signaling(e.g. DSS1)

Signaling(e.g. SIP)

Voice Info(VoIP)


4/13

Functions of Gateways andGateway Controllers

MG SignalingHandlingFunction

MediaGatewayFunction

GatewayControl

Function

Voice -Information(TDM)

Signaling(e.g. SS7)

Voice-Information(VoIP)

MGCP or MEGACO


5/13

Advantages & Disadvantages ofthe Distributed Functionality

Advantages

standardised open architecture

not limited to IP

media gateway simplicity

ease of integration

scalable solution

Disadvantages

central point of failure

delay


6/13

MEGACO, Beispiel 1MEGACO, Beispiel 1

Media Gateway

Null Context

Media Gateway

Null Context

Idle phys.terminations

Context C1

RTP-Term.T1

TDM-Term.T2

TDM-Term.T2

Context = $ {Add = T2, Add = $}

phys. terminations (semi-permanent)

ephemeral terminations (only present during call)


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MEGACO Terminology

Termination: end-point of a media stream

Context: a relationship between terminations

Transaction: group of actions + TID

Command: e.g. Add, Subtract, Modify, Move, Notify

Descriptor: parameters used within a command


8/13

MEGACO or MGCP

Media Gateway

SignallingGateway

SignallingGateway

Media GatewayController

SS7/ISUP SIP, H.323

trunk RTP/UDP

MEGACOor

MGCP


9/13

MEGACO vs MGCP

MEGACO vs MGCP

Both serve the same purpose butMEGACO introduces some new names

and concepts

The new concepts optimise the protocolrather than introducing fundamentally

new features

MEGACO supports Multi-media

applications, MGCP does not

Similar number of messages &flows. Similar capabilities. MEGACO

is more complex.

MGCP is text encoded (BNF).MEGACO is text encoded (ABNF) and

in Binary Form (ASN1)

MGCP: 1 Transaction = 1 CommandMEGACO: 1 Transaction = n Actions

1 Action = n Commands


10/13

Command Sets

MEGACO MGCPAdd termination

Subtract termination

Modify termination

Service change

Notify

AuditValue

Move

Audit Capabilities

Create connection

Delete connection

Modify connection

Notification request

Endpoint confiuration

Restart in progress

Notify

AuditEndpoint

AuditConnectionMove

- - -


11/13

MGCP Connection Set Up

MediaGatewayController

VoIP MediaGatewayA - Side

VoIP MediaGatewayB - Side

2.Evaluates the dialedtelephone number

MG MG


12/13

MEGACO Connection Set Up

MediaGatewayController

VoIP MediaGatewayA - Side

VoIP MediaGatewayB - Side

2. Evaluates thedialed telephonenumber

MG MG

Termi-nationNo. 10 Term.

No. 11

Term.

No. 21

Term.No. 20


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MEGACO Connection Set Up Details

MG

4:Context = $Add= 10,Add = $

5:Reply Context = abcAdd = 10,Add = 11

{local parameter (SDP)}

8:Context = abcModify= 11

{remote param. (SDP)}

9:Reply Context = abcModify = 11

Create Transaction,Create RTP-Term.,

Choose localsession parameter

Add remotesession parameterto transaction data

MG

6: Context= $Add= 20,Add= $

{remote parameter (SDP)

7: Reply Context = xyzAdd = 20,Add = 21{local parameter (SDP)}

Create Transaction,Create RTP Term.,choose localsession parameter

Documents

MGCP_ MEGACO