Download SIP & SS7

SIP & SS7
James Rafferty, Cantata
Technology
Agenda
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
• Overview
• SS7 + SIP in the Converged Network
• SIP and SS7
–
–
–
–
Applicable Standards
Use Cases
Challenges
What’s Ahead?
• Resources
• Summary
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Overview
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
• SIP (Session Initiation Protocol) has won the IP
Standards Wars
• SIP is an important part of the current and
emerging IP Networks
– Most new deployments use SIP
– SIP is the key protocol for the IP Multimedia Subsystem
(IMS)
• SS7 is the dominant signaling protocol used on
Landline and Wireless networks
– It has been particularly successful for 2nd generation
wireless networks
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SS7 + SIP in Converged Network
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
• SS7 will typically be found on the edge of the
converged network
– ISUP (ISDN User Part) used for Call Control
– TCAP (Transaction Capabilities Application Part) used
for various database lookups such as Local Number
Portability (LNP) and Caller Name Lookup (CNAM)
• SIP used for backhaul of signaling or in the core
between gateways
• SS7 can either be converted to SIP or transported
via SIP-T
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SIP and SS7 - Applicable Standards
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
• Key SS7 Standards are from ITU, ETSI and ANSI
– Country specific variants are very common; usually based on ITU or
ANSI
• Latest SIP Standard is RFC 3261
– Many additional RFCs which document additional methods
• Several standards for SIP – SS7 interworking
– IETF RFC 3372 – SIP-T
• Transfer ISUP elements via SIP with MIME body parts
– IETF RFC 3398: SIP – SS7 Mapping
• Map ISUP parameters to SIP headers (where available)
– ITU-T Q.1912.5: More extensive SIP-SS7 Mapping with “SIP-I”
• SIP-I extends beyond SIP-T ; includes more SS7 fields
– 3GPP TS 29.163: Similar to Q.1912.5
• This is part of the IMS suite of standards
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Use Case: SS7 to SIP Conversion
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
Signal
Transfer
Point
SS7
ISUP
SS7
ISUP
PLMN
SS7
ISUP
SIP
IP
Network
SIP
IP
Phone
Cell
Phone
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Use Case: SS7 Bridging via SIP-T
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
Signal
Transfer
Point
Signal
Transfer
Point
SS7
ISUP
SS7
ISUP
PLMN/RAN
IP
Network
SS7
ISUP
SIP - T
SS7
ISUP
PLMN/RAN
RAN
Protocols
RAN
Protocols
Cell
Phone
Cell
Phone
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Use Case: Privacy of Identity
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
Enforce
CLIP/CLIR setting
on
SIP Identity
Headers
CLIP/CLIR
service on
Privacy of
Identity
Signal
Transfer
Point
SS7
ISUP
SS7
ISUP
PLMN
SS7
ISUP
SIP
IP
Network
SIP
IP
Phone
Cell
Phone
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Challenges
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
• Tremendous amount of SS7 based infrastructure in
place
– Transition strategies for using SS7 and SIP together are
critical to manage capital expenditures
• SS7 variants require switches and gateways which
support the variants
• Non-standard uses of SIP are common and hard to
eliminate once in the network
• Interop between equipment from different vendors
is a “way of life” for the converged network
– Best of Breed Enabling Technology Components
– Creates opportunities for System Integrators
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What’s Ahead?
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
• Lots of momentum behind IMS, which uses both
SIP and SS7
– More formal model for SIP use at core
– SS7 used at the edges and converted to SIP or SIP-I
IMS Architecture Example
• Many operators not waiting for IMS
– Wireline vendors making extensive use of SIP “as is”
– SS7 network in place and working; easier to add SIP for
backhaul or new services
• SS7 is well entrenched for services and will remain
in place for years to come
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IMS Architecture
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
IP Multimedia Networks
Legacy mobile
signalling Networks
CS Network
Mm
Mb
Mb
CS
BGCF
SS7 signaling
converted at edge
I-CSCF
AS
Mm
CS
Mk
Mk
ISC
Mw
Mj
Sh
Cx
C, D,
Gc, Gr
BGCF
Mi
Cx
IMMGW
MGCF
Mc
MRFP
MRFC
Mp
Mb
Mb
Mg
Mr
Mb
Mb
HSS
S-CSCF
Dx
SLF
Mw
Dx
P-CSCF
UE
Gm
Ut
IMS Subsystem
3GPP TS 23.228 V7.2.0 (2005-12)
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Resources
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
• Internet Engineering Task Force: www.ietf.org
– Provides RFCs for SIP, RTP and some aspects of SS7 / IP
interworking
– Hitchhiker’s Guide to SIP:
• http://www.ietf.org/internet-drafts/draft-ietf-sip-hitchhikers-guide-03.txt
• International Telecommunications Union: www.itu.int
– Develops SS7 series of recommendations and NGN
• Third Generation Partnership Program (3GPP):
www.3GPP.org
– Develops IP Multimedia Subsystem and related standards
• Cablelabs: www.cablelabs.org
– Develops standards for Cable use of IMS
• Article: Integration of SIP and SS7 for Voice over IP
– http://www.tmcnet.com/sip/0307/feature_articles_integration_of_sip
_ss7_for_voip.htm
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Summary
September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
• SS7 remains the dominant signaling protocol in
today’s network
• SIP is the key next generation VoIP Protocol
• Integration of SS7 and SIP critical to leverage
existing operator investments
• Several strategies possible for transition to more IP
centric infrastructure
• Many vendors using SIP to build new services on
their existing SS7 network
• IMS is coming, but not the only way forward for
operators making IP investments
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September 10-12, 2007 • Los Angeles Convention Center • Los Angeles, California
Thank You!
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