it symposium 2005 7 april 2005
play

IT-Symposium 2005 7. April 2005 VoIP mit Asterisk PBX Voice over - PDF document

Sep 25, 2023 •40 likes •260 views

IT-Symposium 2005 7. April 2005 VoIP mit Asterisk PBX Voice over IP Telephonie mit Asterisk Nebenstellenanlagen John R. Covert DECUS-Mnchen Symposium 2005 3E06 VoIP Technologiesituation Netzprotokolle Asterisk PBX-Konfiguration

  1. IT-Symposium 2005 7. April 2005 VoIP mit Asterisk PBX Voice over IP Telephonie mit Asterisk Nebenstellenanlagen John R. Covert DECUS-München Symposium 2005 3E06 VoIP � Technologiesituation � Netzprotokolle � Asterisk PBX-Konfiguration � Soft/ATA Klient-Konfiguration � Demo www.decus.de 1

  2. IT-Symposium 2005 7. April 2005 Technologiesituation � VoIP am Anfang: intern, auf privater Infrastruktur � Jetzt: im öffentlichen Internet � Hunderte von Providern � PC <--> PC, PC <--> PSTN � ATA (analog telephone adapter) Softphone � Telephonieren vom PC � Viele Produkte, auch kostenlose X-Lite SJphone www.decus.de 2

  3. IT-Symposium 2005 7. April 2005 Analog Adapter � Cisco ATA-186 � Sipura (tiptel in Deutschland) � HandyTone � FRITZ!box � GrandStream (VoIP Telephone) Voice over IP auf dem Vor mar sch � Jeder siebte Deutsche w ill per Inter net telefonier en � Schon acht von zehn Deutschen kennen Inter net- Telefonie � 44 Pr ozent begeister t von Einsatzmöglichkeiten � 14 Pr ozent planen Einstieg binnen zwölf Monaten � Niedr ige Kosten und Zusatzfunktionen über zeugen � Neue Studie von Roland Ber ger Mar ket Resear ch (VoIP News 4.4.2005) � � Gute Infoquelle: http:/ / www.ip- phone- for um.de/ www.decus.de 3

  4. IT-Symposium 2005 7. April 2005 Anbieter für Deutschland � AdvanceCall � GMX NetPhone � babble.net � Nikotel � BlueSIP � PURtel � Br oadnet � Sipgate � dus.net � Sipsnip � WEB.DE Fr eePhone � fr eenet iPhone Sipgate.de � Kostenlose verteilung geographischer bzw 01801 Nummer � Portierung ca. 4. Quartal 2005 � Softphone, Analog Adapter, Asterisk � Kostenfrei zu anderen VoIP Numm er � Verkauft ggf Analog Adapter � Pre-pay � Billige Minutenpreise www.decus.de 4

  5. IT-Symposium 2005 7. April 2005 Einstieg � Softphone dow nloaden, ggf. ATA � Bei einem Anbieter kostenlos anmelden (D-PSTN Rufnummer) � Kostenlose Seattle(Umgebung) Rfnr � Ankommende Gespräche kostenfrei � Gespräche an VoIP-Teilnehmer auch � Konto aufladen: ins PST N anrufen Bequemer Telefonieren � ATA oder VoIP kaufen � Normale Telefone anschließen � ggf VoIP Nebenstellenanlage (OpenSource Asterisk) einsetzen � Bei mehreren Providern anmelden � Least-cost Routing in Asterisk www.decus.de 5

  6. IT-Symposium 2005 7. April 2005 Kostenlos in die USA � Kostenlose SIP-Adresse (Provider) � Kostenlose 360 Area Code N r bei IPKall.com auf die SIP-Adresse � Amazon Yellow Pages (yp.a9.com) • Firma in den Yellow Pages suchen • 360-Nummer klingelt hier in Deutschland • Verbindung geht dann an die Firma • Hilton Disney Wor ld ht t p:// w w w .amazon.com/ gp/yp/ B0004UDK2G/ 002- 8827715- 4872835 Netw erkprotokolle � SIP - Session Initiation Protocol RFC 3261 � RTP/RTCP - Protocol for Real-Time RFC 1889 � STUN - Simple Traversal UDP N AT RFC 3489 � Auch H.323, IAX, RFC2833(DTMF), ... www.decus.de 6

  7. IT-Symposium 2005 7. April 2005 SIP - Session Initiation Anruf machen: -> INVITE <- SIP 407 Proxy-Authentica tion-Required -> ACK -> INVITE mit Authentifizierung (MD5) <- SIP 100 Trying <- SIP 183 Session Progress <- SIP 200 OK -> ACK SIP - Details (1 ->) INVITE sip:080 0225 5288 @ sip.covert.org SIP/2.0 Contac t: <sip:x25@ 6 2.8.199 .106:506 0> Call-ID: E0AF5 2A6-1DD1-11B2-9 801-F6 0C9CB026 9B@ 192 .168.2.1 Content-Type: applica tion/sdp From: "John Covert"<sip:x25@ sip.covert.org>;tag=39 1186 259 1491 7931 25 CSeq: 1 INVITE Max -Forw a rds: 70 To: <sip:0800 2255 288 @ sip.covert.org> Via: SIP/2.0/UDP 192 .168.2.1;rport;branc h=z9hG4bKc 0a80 2010 131 c9b1 4253 cb04 297 413fe 000 0000 7 User-Agent: SJLabs-SJphone /1.30.25 6b Content-Length: 366 www.decus.de 7

  8. IT-Symposium 2005 7. April 2005 SIP - Details (2 <-) SIP/2.0 4 07 Proxy Authentication Required Via: SIP/2.0/UDP 192 .168.2.1;rport;branc h=z9hG4bKc 0a80 2010 131 c9b1 4253 cb04 297 413fe 000 0000 7;rece ived=62.8.1 99.106 From: "John Covert"<sip:x25@ sip.covert.org>;tag=39 1186 259 1491 7931 25 To: <sip:0800 2255 288 @ sip.covert.org>;tag=a s28f7f493 Call-ID: E0AF5 2A6-1DD1-11B2-9 801-F6 0C9CB026 9B@ 192 .168.2.1 CSeq: 1 INVITE User-Agent: Asterisk PBX Allow : INVITE, ACK, CANCEL, OPTIONS, BYE, REFER Contac t: Proxy-Authe nticate : Digest rea lm="asterisk", nonce ="2ed9 f3e8 " Content-Length: 0 SIP - Details (3 ->) ACK sip:080022 5528 8@ sip.covert.org SIP/2 .0 Content-Length: 0 Call-ID: E0AF5 2A6-1DD1-11B2-9 801-F6 0C9CB026 9B@ 192 .168.2.1 Max -Forw a rds: 70 CSeq: 1 ACK From: "John Covert"<sip:x25@ sip.covert.org>;tag=39 1186 259 1491 7931 25 To: <sip:0800 2255 288 @ sip.covert.org>;tag=a s28f7f493 Via: SIP/2.0/UDP 192 .168.2.1;bra nch=z9hG4 bKc0 a802 0101 31c9 b142 53c b042 9741 3fe0 000 0 007 www.decus.de 8

  9. IT-Symposium 2005 7. April 2005 SIP - Details (4.0 ->) INVITE sip:080 0225 5288 @ sip.covert.org SIP/2.0 Content-Length: 366 Contac t: <sip:x25@ 6 2.8.199 .106:506 0> Call-ID: E0AF5 2A6-1DD1-11B2-9 801-F6 0C9CB026 9B@ 192 .168.2.1 Content-Type: applica tion/sdp From: "John Covert"<sip:x25@ sip.covert.org>;tag=39 1186 259 1491 7931 25 CSeq: 2 INVITE Max -Forw a rds: 70 To: <sip:0800 2255 288 @ sip.covert.org> Via: SIP/2.0/UDP 192 .168.2.1;rport;branc h=z9hG4bKc 0a80 2010 000 0018 4253 cb04 03c c9df5 000 0000 9 User-Agent: SJLabs-SJphone /1.30.25 6b Proxy-Authorization: Digest userna me="x25 ",realm="asterisk",nonc e="2ed9f3e 8",uri="sip:08002 255 28 8@ sip.covert.org",response="7fe1 983 6112 2847 084e 888 0081 7a85 c3" SIP - Details (4.1 ->) v=0 o=- 332 1776 515 3 3217 7651 5 IN IP4 6 2.8.199.1 06 s=SJphone c=IN I P4 62.8.19 9.106 t=0 0 a=dire ction:active m=audio 1638 4 RTP/AVP 0 8 3 97 98 1 10 101 a=rtpm ap:0 PCMU/8 000 a=rtpm ap:8 PCMA/80 00 a=rtpm ap:3 GSM/8 000 a=rtpm ap:97 iLBC/80 00 a=rtpm ap:98 iLBC/80 00 a=fmtp:98 mode=20 a=rtpm ap:110 speex/8 000 a=rtpm ap:101 te lephone-event/8000 a=fmtp:101 0-1 1,16 www.decus.de 9

  10. IT-Symposium 2005 7. April 2005 SIP - Details (5 <-) SIP/2.0 1 00 Trying Via: SIP/2.0/UDP 192 .168.2.1;rport;branc h=z9hG4bKc 0a80 2010 000 0018 4253 cb04 03c c9df5 000 0000 9;rece ived=62.8.1 99.106 From: "John Covert"<sip:x25@ sip.covert.org>;tag=39 1186 259 1491 7931 25 To: <sip:0800 2255 288 @ sip.covert.org>;tag=a s671c1 c5f Call-ID: E0AF5 2A6-1DD1-11B2-9 801-F6 0C9CB026 9B@ 192 .168.2.1 CSeq: 2 INVITE User-Agent: Asterisk PBX Allow : INVITE, ACK, CANCEL, OPTIONS, BYE, REFER Contac t: <sip:08002 2552 88@ 2 4.63.81 .3> Content-Length: 0 SIP - Details (6.0 <-) SIP/2.0 1 83 Session Progress Via: SIP/2.0/UDP 192 .168.2.1;rport;branc h=z9hG4bKc 0a80 2010 000 0018 4253 cb04 03c c9df5 000 0000 9;rece ived=62.8.1 99.106 From: "John Covert"<sip:x25@ sip.covert.org>;tag=39 1186 259 1491 7931 25 To: <sip:0800 2255 288 @ sip.covert.org>;tag=a s671c1 c5f Call-ID: E0AF5 2A6-1DD1-11B2-9 801-F6 0C9CB026 9B@ 192 .168.2.1 CSeq: 2 INVITE User-Agent: Asterisk PBX Allow : INVITE, ACK, CANCEL, OPTIONS, BYE, REFER Contac t: <sip:08002 2552 88@ 2 4.63.81 .3> Content-Type: applica tion/sdp Content-Length: 207 www.decus.de 10

  11. IT-Symposium 2005 7. April 2005 SIP - Details (6.1 <-) v=0 o=root 3427 3 427 I N IP4 24.63 .81.3 s=session c=IN I P4 24.63 .81.3 t=0 0 m=audio 2560 4 RTP/AVP 0 8 101 a=rtpm ap:0 PCMU/8 000 a=rtpm ap:8 PCMA/80 00 a=rtpm ap:101 te lephone-event/8000 a=fmtp:101 0-1 6 (n.b. Asterisk kann noch mehr Audioformat e) SIP - Details (7 <-) SIP/2.0 2 00 OK Via: SIP/2.0/UDP 192 .168.2.1;rport;branc h=z9hG4bKc 0a80 2010 000 0018 4253 cb04 03c c9df5 000 0000 9;rece ived=62.8.1 99.106 From: "John Covert"<sip:x25@ sip.covert.org>;tag=39 1186 259 1491 7931 25 To: <sip:0800 2255 288 @ sip.covert.org>;tag=a s671c1 c5f Call-ID: E0AF5 2A6-1DD1-11B2-9 801-F6 0C9CB026 9B@ 192 .168.2.1 CSeq: 2 INVITE User-Agent: Asterisk PBX Allow : INVITE, ACK, CANCEL, OPTIONS, BYE, REFER Contac t: <sip:08002 2552 88@ 2 4.63.81 .3> Content-Type: applica tion/sdp Content-Length: 207 [Conte nts sind dem vorigen Nachric hten gle ich] www.decus.de 11

  12. IT-Symposium 2005 7. April 2005 SIP - Details (8 ->) ACK sip:080022 5528 8@ 2 4.63.81 .3 SIP/2.0 Content-Length: 0 Contac t: <sip:x25@ 6 2.8.199 .106:506 0> Call-ID: E0AF5 2A6-1DD1-11B2-9 801-F6 0C9CB026 9B@ 192 .168.2.1 Max -Forw a rds: 70 CSeq: 2 ACK From: <sip:x25 @ sip.covert.org>;tag=3 9118 625 9149 1793 125 To: <sip:0800 2255 288 @ sip.covert.org>;tag=a s671c1 c5f User-Agent: SJLabs-SJphone /1.30.25 6b Via: SIP/2.0/UDP 192 .168.2.1;rport;branc h=z9hG4bKc 0a80 2010 131 c9b1 4253 cb08 6e9 641c 5 000 0000 d Und jetzt laufen also die RTP-Paketen. SIP - Weitere Funktionen � Anruf beenden • -> BYE • <- OK � Registrieren • -> REGISTER • <- SIP Trying • <- SIP 407 Proxy-Authentication... www.decus.de 12

  13. IT-Symposium 2005 7. April 2005 SIP - Weiteres � Weiterleiten • REFER (RFC 3515) � Ausloggen: • REGISTER m it Expires: 0 � Informieren • OPTIONS RTP/RTCP � Audio-Paketen • PCMU (µlaw ) • PCMA (alaw ) • GSM • SPEEX • iLBC • ... www.decus.de 13

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend

2005 2005

2005 2005

Outline of the settlement for FY2006 2005 2005 2005 and result forecast for

248 views • 14 slides
Re : Cap Speakers Corner April 2005 April 1, 2005 Virginia Tax Study Group Location:

Re : Cap Speakers Corner April 2005 April 1, 2005 Virginia Tax Study Group Location:

Re : Cap Speakers Corner April 2005 April 1, 2005 Virginia Tax Study Group Location: University of Virginia School of Law Speaker: Mortimer M. Caplin Mr. Caplin will chair and speak at the Washington Group Session. April 11-12, 2005 The

433 views • 4 slides
IREANN 27 SEANAD E 395 De Ce adaoin, 27 Aibrea n, 2005 Wednesday, 27 th April, 2005

IREANN 27 SEANAD E 395 De Ce adaoin, 27 Aibrea n, 2005 Wednesday, 27 th April, 2005

IREANN 27 SEANAD E 395 De Ce adaoin, 27 Aibrea n, 2005 Wednesday, 27 th April, 2005 10.30 a.m. RIAR NA hOIBRE Order Paper POIBLI GNO Public Business 1. ( l ) An Bille um Ghairmithe Sla inte agus Cu raim Sho

236 views • 12 slides
Dare to Lead Myron Tribus Pensacola, FL In2:InThinking Network 2005 Forum April 7 10, 2005

Dare to Lead Myron Tribus Pensacola, FL In2:InThinking Network 2005 Forum April 7 10, 2005

Dare to Lead Myron Tribus Pensacola, FL In2:InThinking Network 2005 Forum April 7 10, 2005 Presenter Contact Information: Email: mtribus@earthlink.net 1 2005 F orum What is Leadership? A leader causes people to do things they

115 views • 8 slides
DECnet-Plus und TCP/IP Evolution of DNA DNA Phases Phase I DECUS IT - Symposium - 1976

DECnet-Plus und TCP/IP Evolution of DNA DNA Phases Phase I DECUS IT - Symposium - 1976

Symposium 2005 DECnet-Plus und TCP/IP Evolution of DNA DNA Phases Phase I DECUS IT - Symposium - 1976 PDP-11 RSX DECUS IT - Symposium - Program to program (task to task) communication - File Transfer 4. April - 8. April 2005 4.

295 views • 18 slides
2005 Half Year Results Presentation 6 months to 1 July 2005 10 August 2005 1 10 August 2005

2005 Half Year Results Presentation 6 months to 1 July 2005 10 August 2005 1 10 August 2005

2005 Half Year Results Presentation 6 months to 1 July 2005 10 August 2005 1 10 August 2005 Driving customers and CCAs profitability through the key drivers Product innovation; Non-carbonated beverage and food expansion;

433 views • 24 slides
MetaData Management 2005 MetaData Management 2005 Toronto IRMAC April 19, 2005 April

MetaData Management 2005 MetaData Management 2005 Toronto IRMAC April 19, 2005 April

Gavilan Research Associates Gavilan Research Associates MetaData Management 2005 MetaData Management 2005 Toronto IRMAC April 19, 2005 April 19, 2005 Toronto IRMAC DAMA Wisconsin April 20, 2005 April 20, 2005 DAMA

931 views • 58 slides
Face detection Bill Freeman, MIT 6.869 April 5, 2005 Today (April 5, 2005) Face detection

Face detection Bill Freeman, MIT 6.869 April 5, 2005 Today (April 5, 2005) Face detection

Face detection Bill Freeman, MIT 6.869 April 5, 2005 Today (April 5, 2005) Face detection Subspace-based Distribution-based Neural-network based Boosting based Some slides courtesy of: Baback Moghaddam, Trevor Darrell,

994 views • 96 slides
Financial Results Presentation for Financial Results Presentation for First Qu First Quarter,

Financial Results Presentation for Financial Results Presentation for First Qu First Quarter,

Financial Results Presentation for Financial Results Presentation for First Qu First Quarter, Fiscal 2005 arter, Fiscal 2005 (Jan. 1 to Mar. 31, 2005) (Jan. 1 to Mar. 31, 2005) April 26, 2005 April 26, 2005 Coca-Cola West Japan Co., Ltd.

740 views • 56 slides
Introduction In This Issue: Introduction page 1 On April 20, 2005, President Bush signed

Introduction In This Issue: Introduction page 1 On April 20, 2005, President Bush signed

April 2005 Introduction In This Issue: Introduction page 1 On April 20, 2005, President Bush signed the Bankruptcy Abuse Prevention and Con- Effective Date page 2 sumer Protection Act of 2005 (sometimes referred to as the

652 views • 7 slides
Relational Data Mining and GUHA Tom Karban DATESO 2005 April 14, 2005 Data Mining AKA

Relational Data Mining and GUHA Tom Karban DATESO 2005 April 14, 2005 Data Mining AKA

Relational Data Mining and GUHA Tom Karban DATESO 2005 April 14, 2005 Data Mining AKA knowledge discovery in databases Practice of automatic search for patterns in large data stores implicit, previously unknown, interesting,

786 views • 21 slides
High Tech Computer Corp 2Q 2005 Review 1H 2005 Results 2005 Business outlook August 30 th 2005

High Tech Computer Corp 2Q 2005 Review 1H 2005 Results 2005 Business outlook August 30 th 2005

High Tech Computer Corp 2Q 2005 Review 1H 2005 Results 2005 Business outlook August 30 th 2005 Disclaimer This presentation and release contains forward-looking statements which may include our future results of operations, financial

401 views • 7 slides
Now Everyone Can Fly Now Everyone Can Fly 2005 Second Quarter Results 2005 Second

Now Everyone Can Fly Now Everyone Can Fly 2005 Second Quarter Results 2005 Second

Now Everyone Can Fly Now Everyone Can Fly 2005 Second Quarter Results 2005 Second Quarter Results 21 st February 2005 21 st February 2005 Disclaimer Now Everyone Can Fly Information contained in our presentation is intended solely

603 views • 35 slides
2005 SPLOST Citizens Review Committee November 18, 2005 Update Meeting SPLOST Collections

2005 SPLOST Citizens Review Committee November 18, 2005 Update Meeting SPLOST Collections

2005 SPLOST Citizens Review Committee November 18, 2005 Update Meeting SPLOST Collections The new SPLOST program went into effect in April 2005. The new SPLOST program went into effect in April 2005. Gwinnett County has received

420 views • 26 slides
Re : Cap Speakers Corner May 2005 May 13, 2005 PALS 2005 Asbestos Litigation Seminar

Re : Cap Speakers Corner May 2005 May 13, 2005 PALS 2005 Asbestos Litigation Seminar

Re : Cap Speakers Corner May 2005 May 13, 2005 PALS 2005 Asbestos Litigation Seminar Location: Orlando, FL Speakers: Elihu Inselbuch, Julie Davis, Nate Finch, Peter Lockwood, Ted Swett, Ron Reinsel Mr. Inselbuch will moderate a panel

462 views • 4 slides
Drucken im Bro DECUS Symposium 2005 Warren A. Viertel Consultant Hewlett Packard GmbH (CCCSC)

Drucken im Bro DECUS Symposium 2005 Warren A. Viertel Consultant Hewlett Packard GmbH (CCCSC)

IT-Symposium 2005 Drucken im Bro DECUS Symposium 2005 Warren A. Viertel Consultant Hewlett Packard GmbH (CCCSC) Agenda DCPS General Description DCPS Update DCPS Current Release V2.4 DCPS Future Release V2.5 New HP

700 views • 21 slides
MOL2NET, 2017 , 3, doi:10.3390/mol2net-03-xxxx 2 chemisorption interactions. These theoretical

MOL2NET, 2017 , 3, doi:10.3390/mol2net-03-xxxx 2 chemisorption interactions. These theoretical

MOL2NET, 2017 , 3, doi:10.3390/mol2net-03-xxxx 1 MDPI MOL2NET, International Conference Series on Multidisciplinary Sciences http://sciforum.net/conference/mol2net-03 Precision Medicine: Carbon Nanotubes as Potential Treatment for Human Brain

357 views • 9 slides
Model Misspecification due to Site Specific Rate Heterogeneity: how is tree inference affected?

Model Misspecification due to Site Specific Rate Heterogeneity: how is tree inference affected?

Model Misspecification due to Site Specific Rate Heterogeneity: how is tree inference affected? Stephen Crotty School of Mathematical Sciences, University of Adelaide October, 2013 Stephen Crotty (School of Math. Sci.) Model Misspecification

803 views • 49 slides
Quantum error correction and fault tolerance John Preskill, Caltech 1 July 2004

Quantum error correction and fault tolerance John Preskill, Caltech 1 July 2004

Quantum error correction and fault tolerance John Preskill, Caltech 1 July 2004 http://www.theory.caltech.edu/~preskill/ph219/ph219_2004.html Quantum error correction Can large-scale quantum computers really be built and operated? Surely

668 views • 51 slides
New existence bounds for decoding transition with Q-LDPC codes: percolation on hypergraphs Leonid

New existence bounds for decoding transition with Q-LDPC codes: percolation on hypergraphs Leonid

New existence bounds for decoding transition with Q-LDPC codes: percolation on hypergraphs Leonid Pryadko UC, Riverside QEC14: Dec 16, 2014 p e + (1 p e )[4 p X (1 p X )] 1 / 2 &lt; ( w Z 1) 1 2[4 q (1 q )] 1 / 2 + w Z p

379 views • 22 slides
Desastertolerance aus der Praxis Andreas Abele Fraunhofer Gesellschaft Stuttgart, RZ-IZS

Desastertolerance aus der Praxis Andreas Abele Fraunhofer Gesellschaft Stuttgart, RZ-IZS

Desastertolerance aus der Praxis Andreas Abele Fraunhofer Gesellschaft Stuttgart, RZ-IZS Nobelstrae 12 70569 Stuttgart Tel.: 0711/970-4703 Email: abele@izs.fraunhofer.de Andreas Abele FhG Stuttgart, RZ-IZS Tel: 0711/970-4703

370 views • 17 slides
15-853:Algorithms in the Real World Error Correcting Codes (cont..) Scribe volunteers: ?

15-853:Algorithms in the Real World Error Correcting Codes (cont..) Scribe volunteers: ?

15-853:Algorithms in the Real World Error Correcting Codes (cont..) Scribe volunteers: ? Announcement: Scribe notes template and instructions on the course webpage 15-853 Page1 General Model Noise introduced by the channel: message

531 views • 32 slides
X E Y (1) Z (2) Z (3) Z Exact inference by enumeration Battery X E Y (1) Z Exact

X E Y (1) Z (2) Z (3) Z Exact inference by enumeration Battery X E Y (1) Z Exact

P

281 views • 5 slides
Faculty/Presenter Disclosure Faculty: [Speakers name] Relationships with commercial

Faculty/Presenter Disclosure Faculty: [Speakers name] Relationships with commercial

CFPC CoI Templates: Slide 1 Faculty/Presenter Disclosure Faculty: [Speakers name] Relationships with commercial interests: Grants/Research Support: PharmaCorp ABC Speakers Bureau/Honoraria: XYZ Biopharmaceuticals Ltd.

248 views • 3 slides

More recommend