Download pdf - 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

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    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

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    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)

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    Functions of Gateways andGateway Controllers

    MG SignalingHandlingFunction

    MediaGatewayFunction

    GatewayControl

    Function

    Voice -Information(TDM)

    Signaling(e.g. SS7)

    Voice-Information(VoIP)

    MGCP or MEGACO

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    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

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    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

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    MEGACO or MGCP

    Media Gateway

    SignallingGateway

    SignallingGateway

    Media GatewayController

    SS7/ISUP SIP, H.323

    trunk RTP/UDP

    MEGACOor

    MGCP

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    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

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    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

    - - -

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    MGCP Connection Set Up

    MediaGatewayController

    VoIP MediaGatewayA - Side

    VoIP MediaGatewayB - Side

    2.Evaluates the dialedtelephone number

    MG MG

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    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


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