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Media Gateway Control Protocol. Introduction Media gateway Control Interface Entity Naming (Endpoint, Call, Connection, CA) Digit Maps Events Commands Protocol Description Call Flow for RGW to TGW Usage of Commands. Introduction. Components. SS7 Network. Internet. Signaling (SS7)

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Media gateway control protocol
Media Gateway Control Protocol

  • Introduction

  • Media gateway Control Interface

    • Entity Naming (Endpoint, Call, Connection, CA)

    • Digit Maps

    • Events

    • Commands

  • Protocol Description

  • Call Flow for RGW to TGW

  • Usage of Commands


Introduction
Introduction

  • Components

SS7 Network

Internet

Signaling

(SS7)

Gateway

SCP

Call

Agent

SIGTRAN

STP

MGCP

MGCP

Residential

Gateway

Trunking

Gateway

Residential

Gateway

Trunking

Gateway

CO

Switch

Residential

Gateway

Trunking

Gateway

RTP


Introduction1
Introduction

  • Types of Media Gateway

    • Trunking Gateway to CO/Switches

    • Residential Gateway to PSTN Phones

    • Access Gateway

    • Business Gateway

  • Concept of Call Agent

    • call control intelligent outside gateways

    • master/slave

    • undefined CA to CA: maybe H.323, SIP+


Introduction2
Introduction

  • Relation with H.323 Standards

Internet

Signaling

(SS7)

Gateway

SS7/ISUP

SIGTRAN

Gatekeeper

Call

Agent

CO

Switch

H.225/RAS

H.225/Q.931

H.245

Terminal

or

Gateway

MGCP

Trunking

Gateway

RTP


H323 sip mgcp
H323, SIP & MGCP

  • H.323 , SIP

    • peer-to-peer

    • internet oriented

    • intelligent endpoint

      • optional GK

    • decentralized

  • Problems

    • maintenance

      • cost & scalability of large systems

    • signaling & media control are coupled

    • interoperability with SS7

  • MGCP

    • client-server

    • traditional telephony

    • intelligent server

      • “dumb” terminal

    • centralized

  • Concept

    • gateway decomposed

      • separate call control from media ports

      • CA, MG, SG

    • interoperability with PSTN


Media gateway control interface
Media gateway Control Interface

  • Endpoints

    • Types

      • Digital Channel

      • Analog line

      • IVR endpoint

    • Naming: GW’s Domain Name + Local Name

      • Local Name

        • physical interface name / circuit number

        • e.g., galant.ccl.itri.org.tw/X35V3+A4/15

      • Wild-carded

        • e.g., galant.ccl.itri.org.tw/X35V3+A4/*

        • e.g., galant.ccl.itri.org.tw/X35V3+A4/$

DS0 endpoint

(Channel)

Analog endpoint

(Connections)

(Line)

IVR endpoint


Media gateway control interface1
Media gateway Control Interface

  • Calls & Connections & Call Agents

    • Call Identifier (Call ID)

      • Created by CA

      • Unique in the Whole System

    • Connection ID

      • Created by GW

      • Unique under Its GW

        • Usage of a Connection ID on the same EP

        • Waiting Period at least 3 minutes

    • CA Identifier (its domain name)

      • Redundant CAs : reliability

      • CA & GW keep “time-to-live” record they read from DNS


Media gateway control interface2
Media gateway Control Interface

  • Digit Map

    • CA ask GW to collect user dialed digits

      • Created by CA

      • Sent to Gateways

    • Usage

      • Gateways detect digits, letters, or timer

        • e.g., (11x|080xxxxxx|03xxxxxxx|002x.T)

      • Match accumulated digits

        • under-qualified, do nothing further

        • matched, send the collected digits to CA

        • over-qualified, send the digits to CA

Inter-digit Timer


Media gateway control interface3
Media gateway Control Interface

  • Events

    • package name(o) / event name

    • package:

      • Generic Media (G)

      • DTMF (D)

      • MF (M)

      • Trunk (T)

      • Line (L)

      • Handset (H)

      • RTP (R)

      • Network Access Server (N)

      • Announcement Server (A)

      • Script

Gateway

Supported packages

Trunk GW (ISUP)

Trunk GW (MF)

Network Access Server

Combined NAS/VOIP GW

Access GW (VOIP)

Access GW (VOIP + NAS)

Residential GW

Announcement GW

G, D, T, R

G, M, D, T, R

G, M, T, N

G, M, D, T, N, R

G, M, D, R

G, M, D, N, R

G, D, L, R

A, R


Media gateway control interface4
Media Gateway Control Interface

  • Commands

    • 9 commands to handle Connection/Endpoints

      • EndpointConfiguration (coding charateristics)

      • NotificationRequest (requested events)

      • Notify (GW : detected events)

      • CreateConnection

      • ModifyConnection

      • DeleteConnection (GW also)

      • AuditEndpoint (query status)

      • AuditConnection (query status)

      • RestartInProgress (GW : taken in/out of service)

    • All commands are acknowledged.

EPCF

RQNT

NTFY

CRCX

MDCX

DLCX

AUEP

AUCX

RSIP


Protocol description
Protocol Description

  • Transactions (simple text format)

    • command

      • header

        • a command line (case insensitive)

        • Action + TransId + Endpoint + Version

          • RQNT 1201 endpoint/1@rgw.net MGCP 1.0

        • a set of parameter lines

        • parameter name (upper case): value

          • X: 0123456789B1 (RequestIdentifier)

          • R: hd (requestedEvent: hang down)

          • S: rg (signalRequest: ring tone)

      • session description


Protocol description1
Protocol Description

  • Transactions

    • response

      • header

        • a response line

        • Response code + TransId + Commentary

          • 200 1201 OK

        • a set of parameter lines (optional)

        • after CreateCX(/MDCX/DLCX/Audit/Restart)

          • I: A3C47F21456789F0 (ConnectionId)

      • session description

        • Session Description Protocol

        • separated from header by an empty line




Call flow for rgw to tgw2
Call Flow for RGW to TGW

  • RQNT(1) : NotificationRequest

    • RQNT 1201 hrd3/15@rgw.whatever.net MGCP 1.0

    • N: CA@ca.whatever.net:5678

    • X: 0123456789AC

    • R: hd(E(R(hu(N)),S(dl),D/(D)))

    • D: (11x|080xxxxxx|57xxxxx|002x.T)

  • ACK to RQNT(1)

    • 200 1201 OK

N: NotifyEntity

X: RequestIdentifier

R: RequestEvents

D: DigitMap

E: Embedded(enable) Request

R: Notification Request

N: Notify immediately

S: Signal Request

D: Digit Map


Call flow for rgw to tgw3
Call Flow for RGW to TGW

  • NTFY(2) : Notify from RGW

    • NTFY 2002 hrd3/15@rgw.whatever.net MGCP 1.0

    • N: CA@ca.whatever.net:5678

    • X: 0123456789AC

    • O: 5721043

  • ACK to NTFY(2)

    • 200 2002 OK

N: NotifyEntity

X: RequestIdentifier

O: ObservedEvent


Call flow for rgw to tgw4
Call Flow for RGW to TGW

  • CRCX(3) : CreateConnection

    • CRCX 1204 hrd3/15@rgw.whatever.net MGCP 1.0

    • C: A3C47F21456789F0

    • L: p:10, a: G.711; G.726-32

    • M: recvonly

    • X: 0123456789AD

    • R: hu

  • ACK to CRCX(3)

    • 200 1204 OK

    • I: FDE234C8

    • Session Description

  • C: CallId

  • L: LocalCXOptions

    • p: packetize period(ms)

    • a: Compression Algo.

  • M: Mode

  • X: RequestIdentifier

  • R: RequestEvents

  • I: ConnectionId


Call flow for rgw to tgw5
Call Flow for RGW to TGW

  • CRCX(4) : CreateConnection

    • CRCX 1205 card6/5@tgw.whatever.net MGCP 1.0

    • C: A3C47F21456789F0

    • L: p:10, a: G.711; G.726-32

    • M: sendrecv

    • Session Description from ACK(3)

  • ACK to CRCX(4)

    • 200 1205 OK

    • I: 32F345E2

    • Session Description

C: CallId

M: Mode

I: ConnectionId


Call flow for rgw to tgw6
Call Flow for RGW to TGW

  • MDCX(5) : ModifyConnection

    • MDCX 1206 hrd3/15@rgw.whatever.net MGCP 1.0

    • C: A3C47F21456789F0

    • I: FDE234C8

    • M: recvonly

    • Session Description from ACK(4)

  • ACK to MDCX(5)

    • 200 1206 OK

C: CallId

I: ConnectionId

M: Mode


Call flow for rgw to tgw7
Call Flow for RGW to TGW

  • RQNT(6) : NotificationRequest

    • RQNT 1207 hrd3/15@rgw.whatever.net MGCP 1.0

    • N: CA@ca.whatever.net:5678

    • X: 012345789AE

    • R: hu

    • S: v (alerting)

  • ACK to RQNT(6)

    • 200 1207 OK

N: NotifyEntity

X: RequestIdentifier

R: RequestEvents

S: SignalRequests


Call flow for rgw to tgw8
Call Flow for RGW to TGW

  • MDCX(7) : ModifyConnection

    • MDCX 1209 hrd3/15@rgw.whatever.net MGCP 1.0

    • C: A3C47F21456789F0

    • I: FDE234C8

    • M: sendrecv

    • X: 012345789AF

    • R: hu

  • ACK to MDCX(7)

    • 200 1209 OK

C: CallId

I: ConnectionId

M: Mode


Call flow for rgw to tgw9
Call Flow for RGW to TGW

  • DLCX(8) : DeleteConnection

    • DLCX 1210 hrd3/15@rgw.whatever.net MGCP 1.0

    • C: A3C47F21456789F0

    • I: FDE234C8

  • ACK to DLCX(8)

    • 200 1210 OK

    • P: PS=1245, OS=62345, PR=780, OR=45123, PL=10, JI=27, LA=48

C: CallId

I: ConnectionId

PS: Packets sent

OS: Octets sent

PR: Packets received

OR: Octets received

PL: Packets lost

JI: Average Jitter (ms)

LA: Average Latency (ms)


Usage of commands
Usage of Commands

  • NotificationRequest()

    • EndpointId,

    • [NotifiedEntity,]

    • [RequestedEvents,]

    • RequestIdentifier,

    • [DigitMap,]

    • [SignalRequests,]

    • [QuarantineHandling,]

    • [DetectEvents,]

    • [encapsulated EndpointConfiguration]

Request

Notify

Request

Time

Quarantine Period

Q

T

Q: process/discard

step/loop (notify)

T: events to detect

during quarantine


Usage of commands1
Usage of Commands

  • CreateConnection()

    • CallId,

    • EndpointId,

    • [NotifiedEntity,]

    • [LocalConnectionOptiona,]

    • Mode,

    • [{RemoteConnectDescptr|SecondEndpointId}]

    • [EncapsulatedNotificationRequest,]

    • [encapsulated EndpointConfiguration]

Hairpin Connection


Usage of commands2
Usage of Commands

  • DeleteConnection()

    • Delete one connection from Call Agent

      • ConnectionId in the parameter line

      • GW : Connection parameters

    • Multiple connection from Call agent

      • only EndpontId (and CallId) in the parameter line

      • GW: No connection parameter

    • From gateway

      • Reason-Code & Connection-Parameters in Command


Mgcp applications 1

TGW

TGW

SGW

SGW

SS7

SS7

PSTN

Switch

IP Switch

IP PBX

PSTN

Switch

MGCP Applications (1)

  • IP Switch

IP Networks

Call Agent


Mgcp applications 2

TGW

TGW

SGW

SS7

PSTN

PBX

PSTN

PBX

IP PBX

MGCP Applications (2)

  • IP PBX

IP Networks

Call Agent