Download - Evolution of Signaling
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The Evolution of Signaling
Dan Rothschild
Director, Engineering
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Slide 2
Contents
Signaling Evolution Overview
SS7 Status Sigtran
Bearer Independent Call Control
Converged Networks
NMS Signaling Products
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Slide 3
Signaling Evolution Overview
1990 2000 2007
Bearer Independent Call ControlBICC
Sigtran: SS7/IP
Call Control
Network Services:800, Calling Name, LNP
Wireless: Mobility, Roaming, SMS
IN: Prepaid, Call Mgmt, Ringback
High Speed Links
SS7
Converged Networks
IP Core IMS Multi-Access
SIP H.248 Diameter
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Slide 4
Signaling Evolution Drivers
Signaling bandwidth requirements for new services
SMS, MMS
Number portability
Push-to-talk, voice call continuity
Presence, location
Transport evolution from TDM to packet IP/Ethernet everywhere
Lower cost, higher bandwidth
Protocol explosion in standards bodies
IETF: SIP, SIP-T, SIMPLE, SIGTRAN
3GPP: R99 (UMTS) , R4 (IP-core), R5, R6, R7 (IMS), .
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Slide 5
Signaling Evolution Stages
Starts in core network
Highly utilized routes replaced for bandwidth/cost reduction
Small number of nodes updated/replaced
Sigtran or BICC deployed here first
Evolves to access networks
For new services and/or bandwidth Interworking with new networks
More equipment impacted: switches, gateways, DSLAMs
Migrates to edge devices last
New service deployments
Enhanced service platforms, application servers, mediaservers
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Slide 6
Overview of SS7
Circuit-switched call control: ISUP, TUP
Non-circuit services: TCAP, SCCP IN-service protocols: INAP, AIN, CAMEL
Wireless services: MAP mobility, HLR, roaming, SMS
Network-based services: 800, calling name, LNP
Signaling Transport: MTP layers 1-3Optimized for 48/56/64 kbps links
High-speed links (full T1/E1) introduced for high-bandwidthpaths
Widely deployed in nearly all networks Wireline and wireless
New service deployments still occurring
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SS7 Protocol Architecture
MTP Layer 1
MTP Layer 2
MTP Layer 3
SCCP
IS-634/BSSAP
TCAP
MSC
ANSI-41
HLR
GSMMAP
INAP/CAMEL ISUP/
TUP
BSSService
Node
Transport layers
Upper layers
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Slide 8
SIGTRAN What is it?
Transport of upper layers of SS7 in IP packets
Replaces the transport layers of SS7 (MTP, SCCP)
Sigtran Architecture Components
SCTP Stream Control Transmission Protocol
Reliable transport for signaling
Adaptation Layers many different ones available Resides on both SG and IP Node
Inter-working function on SG
Mapping between IP addresses and SS7 point codes
Multiplexing SS7 interface to multiple IP Nodes
ISUP, TCAP reside on IP Node
(Optional) IPSEC on IP node and SG
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Sigtran Adaptation Layers
One for each different signaling protocol
MTP-2 adaptation layers (M2UA/M2PA)
MTP-3 adaptation layer (M3UA)
SCCP adaptation layer (SUA)
Provides status and network management services
in addition to data transfer Upper adaptation layers support various redundancy
models
Primary/backup
Load sharing
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Slide 11
Packet NetworkPSTN/SS7
PC=10-1-30IP=1.2.3.10STPSTP
SSP
SSP
STPSTP
IP
SCTP
M3UA SUAISUP TCAP
Application
MTP2
MTP3
IP
SCTP
SCCP SUA M3UA
IWF
SGSG
PC=10-1-255
PC=10-1-10
PC=10-1-20
PC=10-1-1
IP=1.2.3.3
IP=1.2.3.2
IP=1.2.3.1MGC
MGC
MGC
Simple Distributed Gateway Architecture
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Current Real World Deployments
AT&T (Cingular) Used M2PA for STP-to-STP hauling of SS7 links
Future plans included: M3UA for MSCs, SMSCs and SCPs
Vodafone Ireland SMSCs
KPN/Netherlands To prepare for IMS infrastructure
China Mobile
SMS traffic again the driver
Just a few examples
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Slide 13
BICC Overview Bearer Independent Call Control
Extension to SS7 ISUP for setting up calls over
packet bearer networks
Can be transported over
SS7 MTP3 or MTP3-b (ATM)
Sigtran M3UA/SCTP
Actual bearer setup protocol can be transportedindependently or tunneled over BICC itself
For RTP/IP bearer networks, SDP can be tunneled over BICCto set up RTP connection
Competes with SIP-T for core network call control
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BICC Capability Sets
Capability set 1 (Q.1901)
Basic call control, ATM-orientation
Forward or Backward Bearer Setup
Codec negotiation + mid-call codec modification
Tear-down bearer at end of call or keep for re-use onanother call
Capability set 2 (Q.1902.x)
IP bearer set-up support
Bearer protocol tunneling
Supplementary services Extension to special resource nodes, via H.248
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Slide 15
BICC Call Setup with tunneled SDP bearer setup
(forward bearer setup)
PSTN-TMCG/MGMGC/MGPSTN-O ISUP
Bearer Established
ISUPBICC
IAM
IAM (connect fwd)
(tunneled SDP Offer)
IAM
ACM
APM (connect fwd)
(tunneled SDP Answer)
APM (connected)
[optional]
ACM
ACM
ANM
ANM
ANM
Note: Many other flows possible
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Slide 16
Gb/IuPS
A/IuCS
SS7
IP/ATM
BTS
BSCMSC Server
VLR
HSSAuC
GMSC server
BSS
SGSN GGSN
CN
C
D
GcGr
Gn Gi
Abis
Gs
B
H
BICC in 3GPP rel5 Architecture:
MSC-Server to MSC-Server Interface (Nc)
2G MS (voice only)
2G+ MS (voice & data)
Node B
RNC
RNS
Iub
3G UE (voice & data)
CS-MGW
CS-MGWNb
PSTN
IuCS
IuPS
IP/ATM
IM
IPPSTN
MGCF
IM-MGW
MRF
CSCF
Mg
Gs
PSTN
McMc
Mc
PSTN
IP Network
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Slide 17
Converged Networks
Packet-switched IP core network (e.g., IMS) Voice, video, data
Common user profile (HSS)
SIP is the dominant signaling protocol
Common services independent of:
Access network Location
Device
Interworking with multiple access networks
Circuit switched and packet switchedWireless, broadband, 2G, 3G, .
Proliferation of protocols can be challenging
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Slide 19
NMS Network Signaling Support
Natural Access
ISDN/CAS
TX 4000TX 4000CTX 4000e
SIPSS7
ISUP BICC TCAP
SigtranM3UA
MTPTDM
VisionSignaling
Server
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Slide 20
SS7 Signaling Boards
TX Series
Support for a full 32 SS7 links and up to 4
high-speed links (HSL) Software-selectable T1 or E1 (120 ohm)
trunks
Full node-level redundancy for highavailability
On-board software, freeing host computer Protocols meet telephony standards,
compatible with all major switches
Variety of form factors and density
Part of the Open Access family
Powerful and flexible solutions for globalSS7 applications
Features
Value Proposition
Benefits
Leverage NMSs worldwide SS7expertise
Scalable hardware with minimum host
loading
Rich and robust API with ITU, ANSIstandards
Competitively-priced, flexible licensing
TX SeriesSignaling
Boards
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Vision Signaling Server
ISUP (ITU and ANSI) signaling for call control
4, 16, or 32 low-speed signaling
links (DS0s) 4 high-speed links (HSL) (DS1s)
Carrier-grade
NEBS-compliant
Redundant, fault tolerant configurations
AC or DC powered
VisionSignaling
Server
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SIP for Natural Access
Uses the Natural Access NCC Service, API
Common programming model simplifies application
development
Supports important extensions for services, such ascall transfer, call hold, and auto attendant
Works with the VoIP service to establish media pathconnections to Natural Access rich mediaprocessing resources
Implemented with RADVISION SIP stack
SIP
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ISDN/CAS
Broad range of TDM signaling protocols
ISDN 11 variants including Euro-ISDN, QSIG ECMA 143, NI-2, Lucent 5ESS
Channel Associated Signaling (CAS)
Worldwide MFC-R2 variants
Many others including CAS R1.5, winkstart, SS5, OPS/OPX,European CAS, digital E&M
Multiple versions of CAS and ISDN can run on a board Selectable during runtime
On-board execution enables efficient call processing whileoffloading the host CPU
PSTNTrunking
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Summary
Signaling network evolution towards converged,SIP-based networks is underway
Transition will take many yearsOperators must leverage existing installed base of SS7
services and equipment
For the next several years, transition technologiesare needed to bridge the gap between todays servicearchitectures and converged networks
NMS signaling products can help smooth the
transition
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Slide 25
Questions?
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NNNN MMMM SSSS COMMUNICATIONS