draft-miniero-mediactrl-escs- 00.txt alessandro amirante tobia castaldi lorenzo miniero simon pietro...

draft-miniero-mediactrl-escs-00.txt

Alessandro AmiranteTobia Castaldi

Lorenzo MinieroSimon Pietro Romano

(University of Napoli Federico II)

University of Napoli - mediactrl WG, 70th IETF meeting, Vancouver, Dec. 3rd 2007

2

Session Control Protocol (SIP) Control Framework (ESCS/SCFW) Call Flow Examples

• This document provides a number of Media Server Control Framework call flows

• It is meant as a BCP document conceived to help the development of the framework specification with a practical approach

• All the flow scenarios come from direct implementation experience, which can help fix potential drawbacks and/or issues emerging in the protocol


3

A Practical Approach

• The document embraces a practical approach by providing:– State Diagrams of the framework protocol

(both AS and MS perspectives);– Some implementation-oriented considerations

that come out of the specification analysis.

• Many real-life scenarios are considered in the call flows, and diagrams with different perspectives are included


4

Call Flows and Diagrams

• Control Channel Establishment• COMEDIA-based negotiation• SYNCH framework transaction

• Use Case Scenarios and Examples– Echo Test

• Direct Echo Test• Echo Test based on Recording

– Phone Call• Direct Connection• Conference-based Approach

– Conferencing• Simple Bridging• Rich Conference Scenario• Coaching Scenario• Sidebars

– Others?

Showed at the demo!

IDLE / TERMINATE

CONTROL RECEIVED

CONTROL PENDING

PENDING SENT

PENDING CONFIRMED

UPDATE SENT

UPDATE CONFIRMED

WAITING FOR LAST

200

CONTROL / -

API 200 / 200

API Error / Error

API 202 / 202

API PENDING / REPORT PENDING

200 / -

API UPDATE / REPORT UPDATE

200 / -

API TERMINATE / REPORT TERMINATE

200 / -

API UPDATE / REPORT UPDATE

API TERMINATE / REPORT TERMINATE

Media Serverperspective

IDLE / TERMINATE

CONTROL SENT

PENDING

UPDATE

200 / -

Error / Error

API CONTROL / send CONTROL

202 / -

REPORT PENDING / send 200

REPORT UPDATE / send 200

REPORT TERMINATE / send 200

REPORT TERMINATE / send 200

REPORT UPDATE / send 200

202 RECEIVED

Application Serverperspective


7

User

OpenSER

University of Napoli Media Server

SIP messages(High speed binary

connector)

Contro

l Ch

annel

SIP messages

SIP signalling

Control Framework signalling

RTP data

RTP communication

Steady-state operation

University of Napoli Application Server

(Wesip)

SIP messages


8

User

OpenSER


(Wesip)


(1)SIP INVITEwith COMEDIA

SIP signalling


TCP

Control channel

Control channelsetup

(2) S

IP IN

VIT

Ew

ith C

OM

ED

IA(3

) SIP

100 T

RYIN

G

(4) SIP 100 TRYING

(5) 2

00 O

K w

ith

CO

MED

IA

(9) T

CP co

nnect

(Contro

l Channel)

(10) S

YN

CH

(D

ialo

g-ID

, etc.)

(11) 2

00

OK

(6) 200 OK with COMEDIA

(7) ACK

(8) A

CK


9

User

OpenSER


(2) SIP INVITE

(1) SIP INVITE

SIP signalling


RTP data

Third Party Call Control(3PCC)

(4) 180 Ringing

(3) 180 Ringing

(6) IN

VIT

E (3

PC

C)

(5) INVITE (3PCC)

(7) 1

00 T

ryin

g

(8) 100 Trying

(9) SDP negotiation with UAC +

tags and labels

mapping

(10) 2

00

OK

(11) 200 OK(12) 200 OK

(13) 200 OK(14) ACK

(15) ACK(16) ACK

(17) A

CK

RTP media streams flowing


(Wesip)


10

RTP media streams flowingThe UAC is echoed back

everything

Control channel

User

OpenSER


SIP signalling


RTP data

Direct Echo example:self connection

(1)C

ON

TR

OL

(join

UA

C to

itself)

(2) 2

02

(3) R

EPO

RT/P

EN

DIN

G

(4) “self-join” UAC

(5) 2

00 O

K(6

) REPO

RT/T

ER

MIN

ATE

(7) 2

00 O

K


(Wesip)


11

Considerations

• Is the 202 message really necessary?– Always followed by a REPORT(pending)

• Ambiguity between notify/update possible states in REPORT messages

• Should notify/update events be possible *after* a terminate?

• Since error messages cannot carry any payload, how are package-specific errors notified?– Should we ‘improperly’ use either the 200 message or the

Report/terminate message for this?• …and others, mostly related to each specific control

package– WIP…


12

Discussion

• Is the document of interest to the WG?• Are the provided scenarios enough? Are

they well described and analyzed?• Should security considerations be in the

scope of this document, or should they just be referenced from the specification documents?

• What else is needed and/or needs to be fixed?


13

Prototype web site

• The prototype implementation and documentation will be soon available at:– http://mediactrl.sourceforge.net

Come and visit us ;-)Contacts:[email protected]@[email protected]@unina.it

http://mediactrl.sourceforge.net/

mailto:[email protected]




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