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15_VoIP3

Apr 05, 2018

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    Tandem/Toll Replacement

    SCPs

    800#LNP

    SS7/C7

    EO

    Toll

    TollTollEO

    EO

    Tan

    TollTan

    EO

    EO

    Packet

    GW GW

    Softswitch

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    PRI Offload for Internet Access

    SS7 IMTs

    TDM

    PRIs

    ISP 1

    ISP 3

    ISP 2RAS

    RAS

    RAS

    EO

    EO

    EO TanMUX

    ScalableSolution

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    PRI Offload for Internet Access

    SS7 IMTs

    PRIs

    ISP 1

    ISP 3

    ISP 2RAS

    RAS

    RAS

    EO

    EO

    EOTan

    Distributed

    Solution

    Packet

    High-SpeedPacket

    Interface

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    PBX Access

    IP

    PBX

    Packet

    GatewaySwitch

    Softswitch

    PBX PRI

    CAS

    SS7

    PBX

    PBX

    ILEC

    SS7 GatewayIMTs

    ILEC

    GatewaySwitch

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    Business Phone Feature Server

    GatewaySwitch

    IPPhones

    PSTN

    Analog/DigitalPhones

    Adapter

    Softswitch

    SS7

    SS7 Gateway

    FeatureServer

    PacketDSL/T1

    IP

    SIP

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    Comparing MGCP and MEGACO

    MGCP comes from the IETFInitial efforts at getting carrier signaling

    into/across IP networks

    RFC2705: MGCP 1.0, 10/1999

    But you cant get this to work without thebig boys (e.g., the Telcos), who meet viathe ITU

    MEGACO is a cooperative effort betweenthe IETF and the ITU

    Future efforts will be/are being focused here

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    More on MEGACO

    MEGACO (MEdia GAteway COntrol) is the IETFname

    In the ITU, its H.248

    RFC3015: MEGACO 1.0, 11/2000

    a little more recent

    MEGACO supports broader range of network types

    (including ATM)

    Good summary article:http://www.networkmagazine.com/article/NMG20001004S0013

    MEGACO Working Group Charter:http://www.ietf.org/html.charters/megaco-charter.html

    http://www.networkmagazine.com/article/NMG20001004S0013http://www.ietf.org/html.charters/megaco-charter.htmlhttp://www.ietf.org/html.charters/megaco-charter.htmlhttp://www.ietf.org/html.charters/megaco-charter.htmlhttp://www.ietf.org/html.charters/megaco-charter.htmlhttp://www.networkmagazine.com/article/NMG20001004S0013

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    The MGCP Model

    Controllers (call agents) control mediagateways

    Gateway does what Call Agent says; master-slave

    E.g., Call Agent tells Gateway to make aconnection from a PSTN connection to an RTPport

    MGCP doesnt address gateway-to-gatewaycommunications

    Generally assumes SIP will do this

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    The MGCP Model (2)

    Two major components in the MGCParchitecture:

    Endpoints: Sources/sinks of traffic within agateway

    e.g., an interface to the PSTNa single call, or acollection of calls (a trunk)

    many different types of endpoints exist (see pp. 241-242)

    Connections: The IP resources allocated to anendpoint to allow communication between theIP and PSTN networks

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    MGCP Connection Establishment

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    MGCP Call Establishmentdetails

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    MGCP Gateway Interaction

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    MGCP with SIP

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    MEGACO Concepts

    Very similar to MGCP Constructs

    Terminationlike an MGCP Endpoint

    Contextlike an MGCP Connection, but morethan that

    more than two Contexts can be associated

    Transactionscommands and responses

    Dual text/binary encodingbinary to accommodate the bellheads

    MEGACO is more peer-to-peer than MGCP

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    MEGACO Call Setup Details

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    Sigtran

    Sigtran is an IETF working group that addresses: signaling performance in IP networks

    interworking signaling between the PSTN and VoIP

    protocols

    IETF Working Group:http://www.ietf.org/html.charters/sigtran-charter.html

    Recent work:

    Security considerations draft, 10/2002

    RFC3331: SS7 MTP2 User Adaptation Layer, 9/2002

    RFC3332: SS7 MTP3 User Adaptation Layer, 9/2002

    http://www.ietf.org/html.charters/sigtran-charter.htmlhttp://www.ietf.org/html.charters/sigtran-charter.htmlhttp://www.ietf.org/html.charters/sigtran-charter.htmlhttp://www.ietf.org/html.charters/sigtran-charter.html

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    Interworking: SIP/MGCP/ISUP

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    Interworking via Sigtran

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    Fully compatible at system level

    Realquestion is whats more appropriate for what application

    Thick vs Thin tradeoff

    Peer (SIP or H.323) end user devices:

    Thick client, functional/peer control model Higher complexity client Feature poor (generic SIP or H.323 relative to current systems) Appropriate for high-end & special purpose devices, soft clients

    Megaco end user devices: Thin client (stimulus-like) control model, low complexity client Shortest path to feature rich system Highly appropriate for mass deployment devices, horizontal features Excellent fit to i2000 goals

    SIP/H.323 vs Megaco Summary

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    Miscellaneous References

    http://www.networkmagazine.com/article/NMG20001004S0013

    http://www.vovida.org/pipermail/mgcp/

    ftp://ftp.rfc-editor.org/in-notes/rfc2705.txt

    ftp://ftp.rfc-editor.org/in-notes/rfc2897.txt

    http://www.ietf.org/html.charters/megaco-

    charter.html

    ftp://ftp.rfc-editor.org/in-notes/rfc3015.txt

    ftp://ftp.rfc-editor.org/in-notes/rfc3054.txt

    http://www.protocols.com/pbook/ss7.htm

    http://www.networkmagazine.com/article/NMG20001004S0013http://www.networkmagazine.com/article/NMG20001004S0013http://www.vovida.org/pipermail/mgcp/ftp://ftp.rfc-editor.org/in-notes/rfc2705.txtftp://ftp.rfc-editor.org/in-notes/rfc2897.txthttp://www.ietf.org/html.charters/megaco-charter.htmlhttp://www.ietf.org/html.charters/megaco-charter.htmlftp://ftp.rfc-editor.org/in-notes/rfc3015.txtftp://ftp.rfc-editor.org/in-notes/rfc3054.txthttp://www.protocols.com/pbook/ss7.htmhttp://www.protocols.com/pbook/ss7.htmftp://ftp.rfc-editor.org/in-notes/rfc3054.txtftp://ftp.rfc-editor.org/in-notes/rfc3054.txtftp://ftp.rfc-editor.org/in-notes/rfc3054.txtftp://ftp.rfc-editor.org/in-notes/rfc3054.txtftp://ftp.rfc-editor.org/in-notes/rfc3054.txtftp://ftp.rfc-editor.org/in-notes/rfc3015.txtftp://ftp.rfc-editor.org/in-notes/rfc3015.txtftp://ftp.rfc-editor.org/in-notes/rfc3015.txtftp://ftp.rfc-editor.org/in-notes/rfc3015.txtftp://ftp.rfc-editor.org/in-notes/rfc3015.txthttp://www.ietf.org/html.charters/megaco-charter.htmlhttp://www.ietf.org/html.charters/megaco-charter.htmlhttp://www.ietf.org/html.charters/megaco-charter.htmlftp://ftp.rfc-editor.org/in-notes/rfc2897.txtftp://ftp.rfc-editor.org/in-notes/rfc2897.txtftp://ftp.rfc-editor.org/in-notes/rfc2897.txtftp://ftp.rfc-editor.org/in-notes/rfc2897.txtftp://ftp.rfc-editor.org/in-notes/rfc2897.txtftp://ftp.rfc-editor.org/in-notes/rfc2705.txtftp://ftp.rfc-editor.org/in-notes/rfc2705.txtftp://ftp.rfc-editor.org/in-notes/rfc2705.txtftp://ftp.rfc-editor.org/in-notes/rfc2705.txtftp://ftp.rfc-editor.org/in-notes/rfc2705.txthttp://www.vovida.org/pipermail/mgcp/http://www.networkmagazine.com/article/NMG20001004S0013http://www.networkmagazine.com/article/NMG20001004S0013