SIP ,SIP-T and SIP-I Protocol

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SIP ,SIP-T and SIP-I Protocol
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Outline

• SIP
• SIP introduction
• SIP Architecture
• Components of SIP
• SIP operation mode
• SIP message structure
• PSTN and SIP interworking
• Interworking architecture
• Protocol overview
• SIP-T
• Whats SIP-T
• Architecture
• Translation of SIP-T
• Encapsulation of ISUP in SIP-T
• SIP-I
• Specification of SIP-I
• TRQ. 2815
• Q.1912.5
• Summary

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SIP Introduction

• Open, simple, extensible, and lightweight
  protocol Design for IP Networks
• Text-encoded protocol based on elements from the
  HTTP and SMTP.
• Same protocol used between services and call
  control entities Text-based encoding
• Easier to integrate with telephony and Internet
  functions Supports multiple call legs (i.e.,
  forking) In order to understanding SIP protocol,
  we need bearing in mind that
• VoIP Signaling Media

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Protocol Stack
SIP
G.711,G.729
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SIP Architecture
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Components of SIP

• User Agents
• User Agent Client (UAC) Send Request (eg.
  inviteetc)
• User Agent Server (UAS) - Responds to clients
  requests (eg. successful ..etc)
• Server
• Proxy Server
• Receive SIP request from UA or other proxy
• Forward or proxies the request to another
  location
• Registrar Server
• Receive SIP registration request
• update user agents information
• Redirect Server
• Receive request from UA or proxy and returns a
  redirection response(3xx)
• Location Server
• It contain user URL,IP address script, feature
• Routing information about Proxies,gateways and
  other Location server in SIP network

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SIP basic operation modes
Proxy Mode
Proxy Server
Peer to Peer Mode
RTP
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SIP Operation in User Registration
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SIP Operation in Proxy Mode
Router
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SIP Operation in Redirect Mode
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SIP message structure

• Request Request-Line
• ( general-header request-header entity-header
  )
• CRLF
• message-body
• Request-Line Method SP Request-URI SP
  SIP-Version CRLF
• Response Status-Line
• ( general-header response-header
  entity-header )
• CRLF
• message-body
• Status-Line SIP-version SP Status-Code SP
  Reason-Phrase CRLF

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Request-Line of request message

• Request-Line Method SP Request-URI SP
  SIP-Version CRLF
• Method
• Register Register to Registrar
• Invite Invite someone to participate in a
  session
• Cancel Cancel the invitation
• Bye Finish the call
• ACK Request confirm
• Options Query a server to its capabilities
• Request-URI SIP-URL without parameter or header
  element
• SIP-Version SIP/2.0
• EX

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Status Line of Response message

• Status-Line SIP-version SP Status-Code SP
  Reason-Phrase CRLF
• SIP-Version SIP/2.0
• Status-Code
• provisional response
• 1xx Informational
• final response
• 2xx - Successful
• 3xx - Redirection
• 4xx - Request Failure
• 5xx - Server Failure
• 6xx - Global Failures
• Reason-Phrase Trying, Ringing

Ex SIP/2.0 100 Trying
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Complete list of response codes
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Request message Headers

• general-header
• Apply to both request and response messages
• -Ex Via, From, To, Call-ID, CSeq, Contact,
  User-Agent
• request-header
• The additional information about the request
• -Ex Proxy-Authorization, Max-Forwards,
• entity-header
• Define meta-info about the message body
• -Ex Content-Length, Content-Type
• The resource identified by the request
• -Ex Allow, Expires
• Refer to RFC 2543 Section 4.1

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SIP Header field
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Message Body

• v0
• oUserB 2890844527 2890844527 IN IP4 there.com
• sSession SDP
• cIN IP4 110.111.112.113
• t0 0
• maudio 3456 RTP/AVP 0
• artpmap 0 PCMU/8000

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SDP Specification

• Session description
• v (protocol version)
• o (owner/creator and session
  identifier).
• s (session name)
• i (session information)
• u (URI of description)
• e (email address)
• p (phone number)
• c (connection information - not
  required if included in all media)
• b (bandwidth information)
• One or more time descriptions (see below)
• z (time zone adjustments)
• k (encryption key)
• a (zero or more session attribute
  lines)
• Zero or more media descriptions (see
  below)
• Time description
• t (time the session is active)

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SIP extensions list
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PSTN and SIP interworking
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Architecture of IP network communication with
PSTN
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Voice IP Protocol overview
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Interworking between PSTN and IP network ISUP
call control signaling
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Introduction of BICC

• ????? SIP ??,??????? PSTN ??? IP
  ???,??????????????????
• BICC???????????????,??ISUP????????,???????????????
  ,?????? TDM ????????? IP ????????????????????????,
  ??????????????????????????,?BICC????,??????
• ???3G???,BICC????3GPPR4???????Nc??,????(G)MSCServe
  r??????????

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SIP-T
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What is SIP-T?

• SIP-T(SIP for Telephones) is define by IETF
• Not an extension to SIP a set of practices for
  interfacing SIP to the PSTN, It provides two key
  characteristics
• Encapsulation of ISUP in SIP
• Translation of ISUP parameters to SIP headers
• Implemented at PSTN gateways, and carried
  end-to-end
• SIP-T Specification families
• RFC3372 SIP for Telephones (SIP-T) Context and
  Architectures
• RFC3398 ISUP to SIP Mapping
• RFC2976 The Session Initiation Protocol (SIP)
  INFO Method
• RFC3204 MIME media types for ISUP and QSIG
  Objects

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IP network interworking with PSTN using SIP-T
architecture
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Translation of SIP-T
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SIP-T scenario 1
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SIP-T scenario 2
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Encapsulation of ISUP in SIP-T

• Extending SIP-T by encoding SS7 ISUP signaling
  messages allows MGCs using SIP-T to be compatible
  with the PSTN.
• SIP-T encodes and transmits the native signaling
  messages from one SCN to another. To do this,
  SIP-T has been extended with MIME encoding of
  signaling messages. The PSTN signaling messages
  are appended to the SIP-T messages (such as
  INVITE, ACK, BYE) using binary encoding.
• The use of MIME encoding with content type
  APPLICATION allows PSTN signaling messages to be
  tunneled between MGCs. The use of content SUBTYPE
  enables SS7 ISUP messages to be differentiated by
  the receiving MGC.

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SIP-T scenario 3
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PSTN-SIP v.s PSTN-SIP-PSTN
INVITE sip1-972-555-2222_at_proxy.carriew.com/user
phone SIP/2.0 Via SIP/2/0/UDP
gw1/carriwe.com5060 From sip1-314-555-2222_at_gw
1.carrier.woo,.comuserphone To
sip1-972-555-2222_at_proxy.carriew.com/userphone C
all-ID12345602_at_gw1.carrier.com CSeq 1
INVITE Contact sip1-314-555-2222_at_gw1.carrier.w
oo,.comuserphone Content-Type
application/sdp Content-length 156 v0 o
GATEway1 2890844527 2890844527 IN IP4
gatewayone.carrier.com sSession SDP c IN IP4
gatewayone carrier.com t 0 0 m audio 3456
RTP/AVP 0 a rtpmap0 PCMU/8000
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SIP-I
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Specification of SIP-I

• SIP-I (SIPwithEncapsulatedISUP ) is defined by
  ITU-T (only draft until now)
• ITU-T Series Q Supplement 45 Technical Report
  TRQ.2815(Requirements for Interworking BICC/ISUP
  Network with Originating/Destination Networks
  based on Session Initiation Protocol and Session
  Description Protocol)
• ???SIP?BICC/ISUP ????????,????????????(Interworkin
  g Unit) ???????????????????????
• ITU-T Recommendation Q.1912.5(Interworking
  between Session Initiation Protocol (SIP) and the
  Bearer Independent Call Control Protocol or ISDN
  User Part)
• Q.1912.5??? SIP?BICC/ISUP?????????????

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TRQ. 2815
Defines the signaling interworking between the
Bearer Independent Call Control (BICC) or ISDN
User Part (ISUP) protocols and Session Initiation
Protocol (SIP) with its associated Session
Description Protocol (SDP) at an Interworking
Unit (IWU)
Profile C supports the trunking of traffic via
transit SIP networks using MIME encoded
encapsulatedISUP (SIP-I)
Profile A was defined to satisfy the demand
represented by 3GPP in TA 24.229 V5.1.0
Profile B complements Profile A, and both of them
are intended to support traffic that terminates
within the SIP network.
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Scenario
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Q.1912.5

• ISUP to SIP/SDP mapping
• Message mapping
• Parameter mapping
• Scope of parameter
• Mapping of ISUP parameters to SIP/SDP
• Initial address message (IAM) mapping to SIP
• Encapsulation

Scenario
Encapsulation format
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ISUP- SIP-I Message mapping
ISUP Acro ISUP Message name SIP message
ACM Address complete 180 Ringing 183 Session progress (profile C only)
ANM Answer 200 OK INVITE
APM Application transport INFO or 183 Session progress
BLA Blocking acknowledgement ISUP side only
BLO Blocking ISUP side only
CCR Continuity check request ISUP side only
CFN Confusion INFO or 183 Session progress
CGB Circuit group blocking BYE 500 Server Internal Error
CGBA Circuit group blocking ACK ISUP side only
CGU Circuit group unblocking ISUP side only
CGUA Circuit group unblocking ACK ISUP side only
CON Connect 200 OK INVITE
COT Continuity UPDATE
CPG Call progress 180 Ringing 183 Session progress (profile C only)
CRG Charge information
CQM Circuit group query
CQR Circuit group query response
DRS Delayed release (reserved  used in 1988 version)
FAA Facility accepted INFO 183 Session progress
FAC Facility INFO 183 Session progress
FAR Facility request INFO 183 Session progress
FOT Forward transfer INFO 183 Session progress
FRJ Facility reject INFO 183 Session progress
NOTE The Release Complete message is a link specific message and may invoke BYE on some legs. NOTE The Release Complete message is a link specific message and may invoke BYE on some legs. NOTE The Release Complete message is a link specific message and may invoke BYE on some legs.
GRA Circuit group reset acknowledgement
GRS Circuit group reset BYE 500 Server Internal Error
IAM Initial address INVITE
IDR Identification request INFO 183 Session progress
IRS Identification response INFO 183 Session progress
INF Information
INR Information request
LPA Loop back acknowledgement
LOP Loop prevention INFO 183 Session progress
NRM Network resource management INFO 183 Session progress
OLM Overload
PAM Pass-along
PRI Pre-release information INFO 183 Session progress
REL Release BYE Message codes
RES Resume INFO 183 Session progress
RLC Release complete BYE (note)
RSC Reset circuit BYE 500 Server Internal Error
SAM Subsequent address
SDM Subsequent directory number
SGM Segmentation Reassembled message ncapsulated.
SUS Suspend INFO 183 Session progress
UBL Unblocking
UBA Unblocking acknowledgement
UCIC Unequipped circuit identification code
UPA User part available
UPT User part test ISUP side only
USR User-to-user information INFO 183 Session progress
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Summary
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Protocol summary
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SIP interworking capability profiles
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Conclusion

• ???????????????,SIP???
• ???????????,SIP???
• SIP-I?????????SIP-T???????SIP-I???????????????,???
  ?CLIP?CLIR??????????????????,???????????????????
  ?????????SIP?BICC/ISUP???,????3GPPSIP?BICC/ISUP???
  ,???
• SIP-I?????ITU-T??????????????,????????
• ??3GPP????Q.1912.5??IMS?PSTN/PLMN??????????,?
  ??SIP??PSTN???????ITU-T?SIP-I?????????????????????
  ?SIP-I????SIP-T?

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Reference

• Keith Mainwaring IP Telephony Migration
  Challenges
• PCC.I-TEL/doc.0202/03, Next Generation Networks
  - Standards Overview (September 2003)
• ITUT Signalling Protocols for NGN Signalling
  Protocols for NGN
• RFC3398-ISUP to SIP Mapping
• RFC3372-SIP-T-Context and Architectures
• ITU-T Recommendation Q.1912.5, modified
• ??? ??????????????????????????
• ??IT ??? ????????????
• Henry Sinnreich Delivering VoIP and Multimedia
  Service with Session Initiation Protocol