ag_sp01_e1_p1 h.248 protocol v1.1 51p

A10&DSL D&T GroupA10&DSL D&T Group

AG_SP01_E1_P1AG_SP01_E1_P1

H.248 ProtocolH.248 ProtocolV1.1V1.1

2ObjectivesObjectives

Upon the completion of this chapter, you will be able to:

Understand the concept of H.248 protocol

Understand the components of H.248 protocol

Describe the Call Flow Scenario (CFS)

3Course OutlineCourse Outline

Concept of H.248 Protocol Components of H.248 Protocol

Call Flow Scenario

4Background storyBackground story

First generation IP phone based on H.323 system

PSTN/ISDN

GW

GK

H323 TerminalMedia translation

Signaling switch

Call control

Limited Function extensibility

Limited system capacity extensibility

5Evolution of H.248Evolution of H.248

6Questions in mindQuestions in mind Who will use H.248 to communicate with each other?

What is the function of H.248

What is the characteristics of H.248

7H.248 ProtocolH.248 Protocol

Softswitch

SG MG

BICC/SIP-T

H.248

RTP/RTCP

SIGTRAN

ISUP/MTP TDM Trunk

Control

Edge

8H.248H.248MG

IAD

Answer of Q1.Answer of Q1.

9Answer of Q2.Answer of Q2. What is the function of H.248?

It is primarily used to separate the call control logic from themedia processing logic in a gateway.

10

Answer of Q3.Answer of Q3. Characteristics:

z ASN.1 and Text encode mode

z Open extensibility

z Better support on multi-media service and multi-meeting

11

Course OutlineCourse Outline

Concept of H.248 Protocol

Components of H.248 Protocol Call Flow Scenario

12

Context and TerminationContext and TerminationMedia GatewayMedia Gateway

ContextsContexts

TerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerm. XTerm. X

TerminationsTerminations

Context. XContext. X

13

Terminology InterpretationTerminology Interpretation Termination

z DefinitionSource and Destination of a media stream. z Semi-permanent termination: physical termination. For example:

ports in a IAD

z Ephemeral termination: a information stream. For example: a RTP voice media.

z Root termination: Device itself.

Contextz Definition: represents the relationship between a group of

terminations. (who hears/sees whom)

z Null context: empty context. Represents terminations that havent establish relationship with others.

14

Connect ModelConnect Model

CONTEXTCONTEXT

TerminationTermination

SCN Bearer SCN Bearer ChannelChannel



Media GatewayMedia Gateway

15

Null ContextNull Context

Null CONTEXTNull CONTEXT





Media GatewayMedia Gateway

16

Call waiting SampleCall waiting Sample

Media Gateway

CONTEXT C1

Term. T2

RTP Stream

Term. T1

SCN Bearer Channel

Term. T3SCN Bearer

Channel

CONTEXT C2

17

Call waiting SampleCall waiting SampleMedia Gateway

CONTEXT C1

Term. T2

RTP Stream

Term. T3SCN Bearer

Channel

CONTEXT C2

Term. T1

SCN Bearer Channel

18

ContextContext Context Characteristic

z ContextID: Identification of Context

z Topology: Direction of media stream flow

z Priority: Priority information related to context

z Emergency call id: identification of emergent call info. Call

19

TerminationTermination Termination ID

z Identification of termination, assigned by MG

Termination descriptorz Property: service status, media passage property

z Event: on_hook, off_hook etc.

z Signal: dialing tone, DTMFsignaling etc.

z Statistics: accumulate statistical data and report to MGC

20

DescriptorDescriptor Descriptor

z Definition: a syntax element (data structure), used

to describe the property of termination

H248 V1. defines 19 descriptors7 categoriesz Status: TerminationState, Modem;

z Media stream: Media_stream, local, remote, local control

multiplex;

z Event related: Event, digitmap, eventbuffer,

Observedevents; Signals;

21

PackagePackage Package

z Definition: systematic extensibility of defining characteristics that havent been defined in termination

Common Packagesz al (analog line management package)

z cg (call procedure management package)

z dd (DTMF detection package)

z au (audio unit package)

22

TransactionTransaction

Sender Receiver

TransactionRequest

TransactionReply/

TransactionPending

TransactionResponseAck

23

TransactionTransactionTransactionRequest(TransactionId {

ContextID {Command _ Command}, . . .

ContextID {Command _ Command } })

TransactionReply(TransactionID { ContextID { Response _ Response },

. . . ContextID { Response _ Response } })

TransactionPending(TransactionID { } )

Transaction

API

Structure

TransactionResponseAck(TransactionID { } TransactionID{ })

24

CommandsCommands

MGMGC

Add

MGCMGAdd a termination to a context, Create a context when contextID is not specified

25

CommandsCommands

MGC

Add

Modify MGCMGModify the property,event or signal parameters of a terminal

MG

26

CommandsCommands

MGC

Add

Modify

subtract

MGCMGDelete a terminal from a contextDelete the context if there is no more terminals in the context

MG

27

CommandsCommands

MGC

Add

Modify

subtract

Move

MGCMGMove a terminal from one context to another

MG

28

CommandsCommands

MGC

Add

Modify

subtract

Move

AuditValue

MGCMGObtain the current status, event, signal and statistics information of a terminal

MG

29

CommandsCommands

MGC

Add

Modify

subtract

Move

AuditValue

AuditCapability

MGCMGObtain the possible capacity (characteristics, event, signal) of a MG

MG

30

CommandsCommands

MGC

Add

Modify

subtract

Move

AuditValue

AuditCapability

Notify

MGMGCAllows the MG to notify the SS for any event change

MG

31

CommandsCommands

MGC

Add

Modify

subtract

Move

AuditValue

AuditCapability

Notify

ServiceChange

MGCMGor MGMGCMGCMG

Start serviceQuit service

MGMGC Start serviceQuit serviceRegistration

MG

32

TransportTransport

Softswitch

MG

H.248

TCP/UDP

IPH.248

Three-way Handshake

Port 2944: Text-encoded

Port 2945: Binary-encoded

33

TransportTransport

Restart timer of every MG is needed to protected against restart avalanche

Timer should be initiate a random value between 0 and a Maximum waiting delay(MWD)

MGC

MG MG MG MG

ServiceChange

Restart Avalanche

34

Course OutlineCourse Outline

Concept of H.248 Protocol

Components of H.248 Protocol

Call Flow Scenario

35

ScenariosScenarios Gateway Log-in/out Call Setup Call Termination

36

Gateway log in/outGateway log in/out

SSIAD

SVC_CHG_REQ

SVC_CHG_REPLY

MEGACO/1 [10.66.100.12]:2944 Transaction = 9998 {

Context = - {

ServiceChange = ROOT {Services {

Method=Restart,

ServiceChangeAddress=2944, Profile=ResGW/1}

}

}

}

MEGACO/1 [10.66.100.1]:2944

Reply = 9998 {Context = -

{ServiceChange = ROOT {Services

{ServiceChangeAddress=2944, Profile=ResGW/1} } }

}

37

SSIAD

NTFY_REQ

MEGACO/1 [10.66.100.12]:2944

Transaction = 49414

{ Context = -

{

Notify = AG58900 {

ObservedEvents = 2000{

20020403T08131100 : al/of

}

}

}

MEGACO/1 [10.66.100.1]:2944

P=49414{C=-{N=AG58900}}

IAD

Off_hook

NTFY_REPLY

Call SetupCall Setup

38

SSIADMEGACO/1 [10.66.100.12]:2944

Reply = 25218

{

Context = -

{

Modify = AG58900

}

}

IAD

MOD_REQ

MOD_REPLYDial-tone

MEGACO/1 [10.66.100.1]:2944 T=25218{ C=-{MF=AG58900{DM=DM999264604954 {(0x.|11x|[2-8]xxxxxxx)},E=2002{dd/ce{ DM=DM999264604954 },al/on,al/fl},SG{cg/dt}}}}


Off_hook

NTFY_REQ

NTFY_REPLY

39

SSIADMEGACO/1 [10.66.100.12]:2944

Transaction = 49415

{

Context = -

{ Notify = AG58900{

ObservedEvents = 2002 {

20020403T08131500 : dd/ce

{ ds = 26778086" , Meth = UM } } } } } MEGACO/1

[10.66.100.1]:2944 Reply=49415{Context=-{Notify= AG58900}}

IAD

NTFY_REPLY

NTFY_REQ


Off_hook

NTFY_REQ

NTFY_REPLY

MOD_REQ

Dial-tone MOD_REPLY

Dialing

40

SSIADMEGACO/1 [10.66.100.12]:2944

Reply = 10003 {

Context = 2000 {

Add = AG58900,

Add=RTP/00000{

Media {

Stream = 1 {

Local {

v=0

c=IN IP4 10.66.100.12m=audio 2222 RTP/AVP 0 4a=ptime:30a=recvonly}}}}}}

MEGACO/1 [10.66.100.1]:2944 Transaction = 10003 {Context = $ {Add = AG58900,Add = $ {Media {Stream = 1 {LocalControl {Mode = ReceiveOnly,nt/jit=40 ; in ms},Local {v=0 c=IN IP4 $ m=audio $ RTP/AVP 0 4a=ptime:30}}}}}}

IAD

ADD_REQ

ADD_REPLY


Off_hook

NTFY_REQ

NTFY_REPLY

MOD_REQ

MOD_REPLY

NTFY_REQ

NTFY_REPLY

41

SSIAD

MEGACO/1 [10.66.100.1]:2944

Transaction = 50003{Context = $ {Add = AG58901 { Media {Stream = 1 {LocalControl{Mode=SendReceive} }},Events=1234{al/of},Signals {al/ri}},Add = ${Media {Stream =1{LocalControl{Mode=SendReceive,nt/jit=40 ; in ms}, Local {v=0c=IN IP4 $m=audio $ RTP/AVP 0 4 8a=ptime:30},Remote {v=0c=IN IP4 10.66.100.12m=audio 2222 RTP/AVP 0 4a=ptime:30} ;}}}}}

MEGACO/1 [10.66.100.13]:2944 Reply = 50003 {Context = 5000 {Add = AG58901,Add = RTP/00002{Media {Stream = 1 {Local {v=0c=IN IP4 10.66.100.13m=audio 1111 RTP/AVP 0}} ; }}}}

IAD

ADD_REQ

ADD_REPLY


Off_hook

NTFY_REQ

NTFY_REPLY

MOD_REQ

MOD_REPLY

NTFY_REQ

NTFY_REPLY

ADD_REQ

ADD_REPLY

ring

42

SSIAD

MEGACO/1 [10.66.100.12]:2944

Reply = 10005

{ Context = 2000

Modify = AG58900

Modify = RTP/00000

}

}

MEGACO/1 [10.41.6.1]:2944 Transaction = 10005 {Context = 2000 {Modify = AG58900 {Signals {cg/rt}},Modify = RTP/00000 {Media {Stream =1 {Remote {v=0c=IN IP4 10.66.100.13m=audio 1111 RTP/AVP 0}} ;}}}}

IAD

MOD_REQ

MOD_REPLYRing_back


43

SSIAD

MEGACO/1 [10.66.100.1]:2944 Reply = 50005 {Context = 5000 {Notify = AG58901}}

MEGACO/1 [10.66.100.13]:2944 Transaction = 50005 {Context = 5000 {Notify = AG58901{ObservedEvents =1234 {19990729T22020002:al/of}}}}

IAD

MOD_REPLY

OffhookNTFY_REQ

NTFY_REPLY


MOD_REQ

Ring_back

44

SSIAD

MEGACO/1 [10.66.100.1]:2944 Transaction = 10006 {Context = 5000 {Modify = AG58901 {{E=2001{al/on,al/fl},Signals { }}}}

MEGACO/1 [10.66.100.13]:2944 Reply = 10006 {Context = 5000 {Modify = AG58901 }}

IAD

MOD_REPLY

Offhook

NTFY_REPLY

MOD_REQ

MOD_RERLY


MOD_REQ

Ring_back

NTFY_REQ

45

SSIAD

MEGACO/1 [10.66.100.12]:2944 Reply = 10006 {Context = 2000 {Modify = AG58900, Modify = RTP/00000}}

MEGACO/1 [10.66.100.1]:2944 Transaction = 10006 {Context = 2000 {Modify = AG58900{ Signals={ } },Modify = RTP/00000{Media {

Stream = 1 {LocalControl {

Mode=SendReceive}}}}}}

IAD

MOD_REPLY

Offhook

NTFY_REPLY

MOD_REQ

MOD_RERLY

MOD_REQ

MOD_REPLY

Conversation Established


MOD_REQ

Ring_back

NTFY_REQ

46

SSIAD

MEGACO/1 [10.66.100.1]:2944 Reply = 50008 {Context = 5000{Notify = AG58901}}

MEGACO/1 [10.66.100.13]:2944 Transaction = 50008 {Context = 5000 {Notify = AG58901{ObservedEvents =1235 {19990729T24020002:al/on} } } }

IAD

NTFY_REQ

NTFY_REPLY

Onhook

Call TerminationCall Termination

47

SSIAD

MEGACO/1 [10.66.100.1]:2944 Transaction = 10007 {Context = 2000 {Modify= AG58900{signals { cg/bt }}}}

MEGACO/1 [10.66.100.12]:2944 Reply = 10007 {Context = 5000 {Modify = AG58900 }}

IAD

NTFY_REPLY

Onhook

MOD_REQ

MOD_REPLY


NTFY_REQ

48

SSIAD

MEGACO/1 [10.66.100.1]:2944 Transaction = 50009 {Context = 5000 {Subtract = AG58901{Audit{Statistics}},Subtract = RTP/00002{Audit{Statistics}}}}

MEGACO/1 [10.66.100.13]:2944 Reply = 50009 {Context = 5000 {Subtract = AG58901 {Statistics {nt/os=45123, ; nt/dur=40 ; }},Subtract = RTP/00002{Statistics {rtp/ps=1245,nt/os=62345,rtp/pr=780, nt/or=45123, rtp/pl=0, rtp/jit=27,rtp/delay=48 }}}}

IAD

NTFY_REPLY

SUB_REQ

SUB_REPLY

Onhook

MOD_REQ

MOD_REPLY


NTFY_REQ

49

SSIAD IAD

SUB_REQ

SUB_REPLY

Onhook

NTFY_REPLY

Conversation Terminated

SUB_REQ

SUB_RERLY

MEGACO/1 [10.66.100.1]:2944 Transaction = 50009 {Context = 2000 {Subtract = AG58900{Audit{Statistics}},Subtract = RTP/00000{Audit{Statistics}}}}

MEGACO/1 [10.66.100.12]:2944 Reply = 50009 {Context = 2000 {Subtract = AG58900 {Statistics {nt/os=45123, ; nt/dur=40 ; }},Subtract = RTP/00000 {Statistics {rtp/ps=1245,nt/os=62345,rtp/pr=780, nt/or=45123, rtp/pl=0, rtp/jit=27,rtp/delay=48 }}}}

MOD_REQ

MOD_REPLY


NTFY_REQ

50

SS7 - H.248 SS7 signalingSS7 - H.248 SS7 signaling

Softswitch

TGTG

SG SG

Database ApplicationServer

ZTE

LS1 ZTELS2

3. Analysis & Routing

1. IAM

2. IAM

4. Add

5. Reply of Add

6. Add

7. Reply of Add

8. IAM11. ACM

9. IA

M10

. ACM

14. ACM

13. ACM

12. Modify(Notify)17. Modify

16. ANM

19. ANM

18. ANM

15. A

NM

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ag_sp01_e1_p1 h.248 protocol v1.1 51p

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