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VoIP Protocol Introduction(MGCP) PKT-SP-EC-MGCP-I10-040402

VoIP Protocol Introduction(MGCP) PKT-SP-EC-MGCP-I10-040402. CONTENTS. 1 SCOPE 2 INTROUDUCTION 3 MGCI 4 MGCP. SCOPE. Describe Media Gateway Control Protocol(MGCP) for Packet Cable Embedded Client Refer to as the Packet Cable NCS( N etwork-Based C all S ignaling) Protocol

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VoIP Protocol Introduction(MGCP) PKT-SP-EC-MGCP-I10-040402

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  1. VoIP Protocol Introduction(MGCP) PKT-SP-EC-MGCP-I10-040402

  2. CONTENTS 1 SCOPE 2 INTROUDUCTION 3 MGCI 4 MGCP

  3. SCOPE Describe Media Gateway Control Protocol(MGCP) for Packet Cable Embedded Client Refer to as the Packet Cable NCS(Network-Based Call Signaling) Protocol Describe MGCI(Media Gateway Control Interface) and MGCP Based on the MGCP ITU-T H.GCP IETF MGCP 0.1 (Draft) MGCP 1.0 (RFC 2705) MEGACO (MGCP 2.0) MGCP 1.0 bis (draft) Packet Cable NCS MGCP 1.0

  4. 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 Architecture Call Agent : Call Control Element Gateway : Conversion audio signals and data packets • Connection Model Basic 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

  5. MGCI MGCI-Model and Naming Conventions • MGCI Functions… Connection Control Endpoint Control Auditing Status Reporting Use 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

  6. MGCI MGCI-Model and Naming Conventions • Model and Naming Conventions • Digit Maps Possible Dialing Numbers(Dial Plan) 0 Local operator *xx Star services 00 Long Distance Operator 91xxxxxxxxx Long Distance Number xxxx Local Exchange Number 9011 + up to 15 digits International number 8xxxxxxx Shortcut to local number at other corporate sites Above Dial Plan can be described in the following Digit Map (0T | 00T | [1-7]xxx | 8xxxxxxx | #xxxxxxx | *xx | 91xxxxxxxxxxxxx | 9011x.T) The Formal syntax of Digit Map Digit ::= “0” | “1” | “2” | “3” | “4” | “5” | “6” | “7” | “8” | “9” Timer ::= “T” | “t” -- matches the detection of timer Letter ::= Digit | Timer | “#” | “*” | “A” | “a” | “B” | “b” | “C” | “c” | “D” | “d” Range ::= “X” | “x” -- matches any digit | “[“ Letters “]” -- matches any of the specified letters Letters ::= Subrange | Subrange Letters Subrange ::= Letter -- matches the specified letter | Digit “-” Digit -- matches any digit between first and last Position ::= Letter | Range StringElement ::= Position -- matches an occurrence of the position | Position “.” -- matches an arbitrary number of occurrence -- of the position, including 0 String ::= StringElement | StringElement String StringList ::= String | String “|” StringList DigitMap ::= String | “(“ StringList “)”

  7. MGCI-Model and Naming Conventions • Model and Naming Conventions • Events and Signals • SDP USE Provide the gateways with the description of connection parameters (IP Address, UDP Port, RTP Profiles..) Notify Events(L/hd) Call Agent Embedded Client Request Signals(L/dl) L/hd : hook-off in line package for an analog access line L/dl : dial-tone in line package for an analog access line

  8. MGCI-Gateway Control Functions • Gateway Control Functions Describe the commands of the MGCP • Notification Request(RQNT) Used to request the gateway to send a notification upon the occurrence of Specified 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 request DigitMap(D) : X.T SignalRequests(S) : rt, rg, bz.. QuarantineHandling(Q) : Optional Parameter DetectEvents(T) : Optional Parameter

  9. MGCI-Gateway Control Functions • 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 RequestedEvents Parameter, 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

  10. MGCI-Gateway Control Functions • 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 connection RecvOlny, Send/recv..

  11. MGCI-Gateway Control Functions • 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 OK P:PS=2, OS=0, PR=306, OR=7344, PL=0, JI=5, LA=0

  12. MGCI-Gateway Control Functions • Auditing(AUEP, AUCX) AuditEndPoint(AUEP): Used by the Call Agent to determine the status of an endpoint AuditConnection(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 EndpointId F: ES, A, I ※ ES : Event Status A : Capabilities 200 TID OK I : Connection ID ES:I/hu A: a:PCMU;G723;G729, s:off

  13. MGCI-Gateway Control Functions • Restart in Progress(RSIP) Used by the gateway to signal that an endpoint, or a group of endpoints, is taken 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 abruptly Restart : 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

  14. MGCI-Return Codes and Error Codes All MGCP commands receive a response. The response carries a return code that 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 Definitions 100 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.

  15. MGCI-Use of Local Connection Options and connection Descriptors CRCX(Local Connection Option) 200 OK SDP:Local Connection Descriptor CRCX(Local Connection Option) SDP:Remote Connection Descriptor 200 OK SDP:Local Connection Descriptor MDCX(Local Connection Option) SDP:Remote Connection Descriptor 200 OK SDP:Local Connection Descriptor Codec and packetization period selection EX) CRCX(L: a:G723) RCD(m=4 18 0 8) 200 OK LCD(m=4)

  16. MGCP- General Description • General Description • Command • Ex) CRCX 2005 aaln/1@mta2.icablesystem.com MGCP 1.0 NCS 1.0 C: 0 L: p:20, a:PCMU;PCMA;G.723.1-5.3;G.723;G.729A, s:on, e:on M: recvonly X: 3 R: hu S: rt • TID(Transaction ID) : Value between 1 and 999999999 Correlate commands and responses Head Body cmd tid Endpoint Name version parameters SDPs

  17. MGCP- General Description • General Description • Response • EX) 200 2005 OK I: 686B v=0 o=- 26731 2005 IN IP4 218.232.96.222 s=- c=IN IP4 218.232.96.222 t=0 0 m=audio 3456 RTP/AVP 0 8 4 18 a=recvonly a=ptime:20 Head Body ReCode tid comment parameters SDPs

  18. MGCP- Command Header Command Line

  19. MGCP- Command Header • 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 the Gateway to use for a connection. These parameters are p, a, s, e etc. • RequestedEvents(R) Provides the list of events that have been requested R: 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 requested S: ci(10/14/17/26, “555 1212”, CableLabs) S : rg S : rt

  20. MGCP- Command Header • Parameter Line • ObservedEvents(O) Provide the list of events that have been observed O: 8,2,9,5,5,5,5,T 0:hf • RequestInfo(F) Contain a comma separated list of parameter codes F: ES,I,A • CallId(C) ,DigitMap(D) EX) CRCX 1120660 isup/1/1/18@x-mg1.hanaro.com MGCP 1.0 C: 22002a4 L: nt:IN, a:G723, fx:t38, e:on, s:off M: sendrecv D: ([0-9*#]) X: 22002a4 R: fxr/t38, D/[0-9*#](D)

  21. MGCP- Response Header Formats • Create Connection The Response line is followed by a Connection-Id parameter witha successful response(code 200). A LocalConnectionDescriptor is furthermore transmitted with a positive response Ex) 200 1204 OK I: FDE234C8 v=0 o=- 25678 753849 IN IP4 128.96.41.1 s=- c=IN IP4 128.96.41.1 t=0 0 m=audio 3456 RTP/AVP 96 97 0 a=rtpmap:96 G726-32/8000 a=rtpmap:97 telephone-event/8000 a=mptime: 10 - 10

  22. MGCP- Response Header Formats • ModifyConnection The response line is followed by a LocalConnectionDescriptor Ex) 200 1207 OK v=0 o=- 25678 753849 IN IP4 128.96.41.1 s=- c=IN IP4 128.96.41.1 m=audio 3456 RTP/AVP 0 a=mptime: 20 • DeleteConnection The response line may be followed by a Connection Parameters parameter line Ex) 250 1210 OK P: PS=1245, OS=62345, PR=780, OR=45123, PL=10, JI=27, LA=48

  23. MGCP- Response Header Formats NotificationRequest/Notify Not include any additional response parameters AuditEndpoint The response line may be followed by information for each of the parameters Requested–each parameter will appear on a separate line. Ex) 200 1200 OK A: a:PCMU; p:10, e:on, s:off, t:1, v:L, AuditConnection The Response may be followed by information for each of the parameters requested Ex) 200 1203 OK C: A3C47F21456789F0 P: PS=622, OS=31172, PR=390, OR=22561, PL=5, JI=29, LA=50,

  24. MGCP- Response Header Formats RestartInProgress The 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 Call Agent as in: 521 1204 Redirect N: CA-1@ca.whatever.net

  25. MGCP- Session Description Encoding SDP Avdio Service Use Protocol Version(V=) Origin(o=) Session Name(s=) Connection Data(c=) Media Announcements(m=) Attributes(a=) Ex) v=0 c=IN IP4 218.232.19.236 m=audio 24830 RTP/AVP 4 a=ptime:30 a=cdsc : 1 image udpt I t38

  26. MGCP- Piggy-Backing Separated by a line of text that contains a single dot 200 2005 OK . DLCX 1244 aaln/2@rgw.whatever.net MGCP 1.0 NCS 1.0 C: A3C47F21456789F0 I: FDE234C8 Used to guarantee in-order delivery of messages Used to Fate-Sharing of message delivery

  27. MGCP- Event Packages Line Package Package 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

  28. MGCP- Residential Gateway Restart Call Agent RMG rsip 1001 *@TEST.0000 MGCP 1.0 RM:restart RD:0 200 1001 OK AUEP 216 aaln/1@test.0000 MGCP 1.0 F: ES,A,I 200 216 OK ES:l/hu A: a:PCMU;G726-32;G723; gc:0, s:off RQNT 217 aaln/1@test.0000 MGCP 1.0 S: X: 210000e Q: discard R: L/hd 200 217 OK

  29. Questions ?

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