МатериалБочкарев С.А. / sip_protocol_en
.pdfhgs/SIP Tutorial |
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The Session Initiation Protocol
(SIP)
Henning Schulzrinne
Dept. of Computer Science
Columbia University
New York, New York
(sip:)schulzrinne@cs.columbia.edu
May 2001
hgs/SIP Tutorial |
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Overview
protocol architecture
typical component architectures
addressing and locating SIP entities
protocol operation and extensions
reliability
services, features and caller preferences
security and QoS
programming SIP services
May 2001
hgs/SIP Tutorial |
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Introduction
SIP = core protocol for establishing sessions in the Internet
transports session description information from initiator (caller) to callees
allows to change parameters in mid-session
terminate session
May 2001
hgs/SIP Tutorial |
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VoIP protocol architecture
Languages/APIs
JAIN
Parlay
Directory/Discovery
DNS/enum LDAP TRIP
SLP
QoS
DiffServ IntServ
CPL voiceXML servlets sip−cgi
peer−to−peer Signaling
SIP SDP |
MGCP |
RTSP |
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H.248 |
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PINT |
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SPIRITS |
master−slave |
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Transport
RTP TLS
SCTP
May 2001
hgs/SIP Tutorial |
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Multimedia protocol stack
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signaling |
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quality of service |
media transport |
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MGCP/Megaco |
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SDP |
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reservation |
measurement |
media encaps. |
H.323 |
SIP |
RTSP |
RSVP |
RTCP |
(H.261, MPEG) |
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RTP |
transport |
TCP |
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UDP |
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network |
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IPv4, IPv6 |
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PPP |
AAL3/4 |
AAL5 |
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PPP |
link |
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Sonet |
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ATM |
Ethernet |
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V.34 |
physical |
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application |
daemon |
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kernel
May 2001
hgs/SIP Tutorial
SIP protocol use
LDAP |
address |
TRIP |
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lookup |
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PSTN gateway lookup |
DNS |
next−hop |
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SIP |
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signaling |
may |
SDP |
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sets up |
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trigger |
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RSVP |
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media |
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RTP |
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UDP |
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SIP
SDP
RSVP
RTP
UDP
May 2001
hgs/SIP Tutorial |
7 |
SIP applications
setting up voice-over-IP calls
setting up multimedia conferences
event notification (subscribe/notify) IM and presence
text and general messaging
signaling transport
May 2001
hgs/SIP Tutorial |
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SIP addressing
May 2001
hgs/SIP Tutorial |
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Personal mobility
SIP uses email-style addresses to identify users
yahoo.com
alice17@yahoo.com
alice@columbia.edu
7000@columbia.edu
Alice.Cary@columbia.edu |
columbia.edu |
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alice@columbia.edu
(also used by bob@columbia.edu)
tel:12128541111
tel:12015551234
alice@host.columbia.edu
May 2001
hgs/SIP Tutorial |
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SIP addressing
typically, same as user's email address:
alice@example.com 12125551212@gateways-r-us.com
written as URL, e.g., sip:alice@example.com
can add parameters, such as type (user=”phone”) or transport protocol
May 2001