ESW – May 2010 UK Architecture for VoIP 999/112s John Medland – BT 999/112 Policy Manager.
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Transcript of ESW – May 2010 UK Architecture for VoIP 999/112s John Medland – BT 999/112 Policy Manager.
UK Emergency Service
BT or CW Public Network
Fixed/MobileNetworks
Stage 1 PSAPs
BT (5) or C&W (2)
Public networks
Police 52%
Ambulance42%
Fire 6%
Coastguard <1%
999/112/ 18000
999/112/18000
(204 Local Controls) (
Public Emergency numbers
- 999/112,
- 18000 (ITU v21 text over voice, ie real time text using special terminals)
•31 million calls each year to stage 1 PSAPs, 55% from mobile phones
•Around 60% are connected to Stage 2 PSAPs (usually within 10 seconds)
Location for emergency callers
• Available automatically on fixed and mobile calls at Stage 1 and Stage 2 PSAPs
• Fixed lines : civic locations as name and address updated daily to Stage 1 PSAP database
• Mobile networks provide cell coverage area (enhanced with timing advance for some) over standard ETSI interface: radius ~2.2km
• Limitations for VoIP calls, calls from private networks, mobile roamers
• Stage 1 PSAPs provide Location Servers which can be accessed by Stage 2 PSAPs ( location retrieved instantly using telephone number + secure TCP/IP link)
• Industry funded Stage 1 PSAPs supply location free to Stage 2 PSAPs (Stage 2 PSAPs pay for their lines, hardware and software)
• Telematics emergency calls (non-standard eCalls) growing and can provide GPS information
Handling VoIP 999 now• PSAPs still TDM based so VoIP goes through PSTN / IP
Gateways• Small number of VoIP 999s at present, mostly fixed users• Regulation says if PSTN access, then must allow 999 • 999s identified as VoIP• Registered “default” address accessed through E164 tel
number (CLI) for “fixed” users….• ….but default address marked as needing voice
confirmationVerbal routing
• Device/CPE use PSTN/GSM for 999 if possible
• Key issues for VoIP 999 : -- only default name+address data from large number of VoIP SPs- challenge of 24 hour VSP contact point for PSAP use (tracing, alternative contact numbers)- lack of information to PSAP for nomadic users
• Need to Automate Location provision………
NICC Task Group• The Network Interoperabilty Consultative Committee : NICC is a
UK telecommunications industry committee which acts as an industry consensus group in which specifications and technical issues associated with network competition can be discussed. It also is a source of technical advice to the UK Regulator
• Location Task Group : Routing 999/112 for VoIP to correct local EA supplying caller location information on all calls
• Membership : BT, C&W, Ericssons, Huawei, Andrew, Nominet, Magrathea, Aeonvista,Vodafone, VirginMedia, Orange, and Ofcom +….
• Approach :-
- VSP, ISP and Access Provider(s) all different organisations- PSAPs are still TDM based- Start with UK only (all parties UK-based) - Cover DSL, Cable, Enterprise, WiFi and GSM scenarios - Use developing standards wherever possible, eg IETF, ETSI- Don’t rely on user- Don’t rely on device
Key
VPC
VoIP call
CLI + VSP1 id
VSP 1Soft-Switch
Emergency Handling Authority –Stage 1 PSAP
Internet service & access infrastructure providers
PIGPIG
CLI + VSP1 id
IAIC
Request using CLI, VSP id.Response gives location
1
c
3
4
b
ISP LIS
SBC2
PSTN—IP Gateway
VSP 2 soft switch (Aggregation + SS7 interconnect )
a
SBC1
SBC1/2
Source IP+Port, VSP 1 ID and CLI information (NENA v2)
Access and IP Log-on functions
2
Voice path
Data path
Overview of Architecture and Interfaces
HELD third party request using Source IP (+ Port no.), in HELD ID extensions. Response gives PIDF-LO
LIS URI IP
VoIP Positioning Centre
VSP Soft Switch
Emergency Handling Agency
ISP LIS
IAIC (IP Address to ISP Converter)
Interface (a)Key Parameters (CLI,
Source Public IP Address, source port number)
Interface ( b)Parameter (Source Public IP Address)
Inteface(b)Parameter (ISP LIS
URI)
Interface ( c )Parameter (Source Public IP Address)
Interface (4)Parameter
(CLI)Interface (4)Parameter(Location)
Interface( c )Parameter (PIDF-LO
Location)
VPC Functions
IAIC
AS / LIS mapping
IP / AS mapping
IP Address
LIS URI
BGP4 Route Collector
BGP Route Updates
Interface (b)
BGP Peers
VPC - Mapping Source IP address to ISP
LIS
HELD Server
IP@ translation; Border Functions - NAPT/SBC/ALG
OSS Systems
Network
elements
Interface (c)
iL2
iM1
iC1
iB1LIS
Other LIS
Generic LIS Functions
Broadband and ADSL Access
IP N/W
Voice
Term
ina
l
Management
Control
Media
Resid
ential
G/W
RADIUSServer
RADIUSServer
LIS VPC
OSSISPOSSBAPOSSLLP
(RADIUS)
(RADIUS)
(RADIUS)
L2T
P A
ccessC
oncen
trator
L2T
P N
etwork
Server
(RADIUS)
DS
LA
M
SIP
RTP/RTCP
Figure E1: xDSL Architecture for PPP Tunnelled via L2TP to ISP
UserEnvironment
Local LoopProvider
Backhaul &Aggregation
Provider
Internet ServiceProvider
EmergencyHandlingCentre
InternetTelephony
ServiceProvider
BB Service Req (Billing Adrs, Inst Adrs)
BB Service Req (RefISP,MPF,Inst Adrs)
BB Service Req (RefBAP, MPF, Inst Adrs)
BB Service Resp (RefBAP,SIDLLP)
LIS Add Info (SIDBAP, Inst Adrs)
BB Inst Adrs Audit Req(List[SIDBAP])
BB Inst Adrs Audit Req(List[SIDLLP])
BB Inst Adrs Audit Resp(List[SIDLLP,Inst Adrs])
BB Inst Adrs Audit Resp(List[SIDLLP,Inst Adrs])
LIS Add/Remove/Modify Info(SIDBAP, Inst Adrs)
OSSISPOSSBAPOSSLLP LISBBCustomer
Figure E5: BB Provision and Audit on a MPF Line For Binding of Service Identifier (SID) to Installation Address (Inst Adrs)
BB Service Resp (RefISP,SIDBAP)
Audit
Provision
Resid
ential
G/W LIS
DS
LA
M
L2T
PA
ggregationC
oncen
trator
ISPRADIUSServer
Figure E2: Network Attachment for PPP Tunnelled via L2TP to ISP
L2T
PN
etwork
Server
BAPRADIUSServer
L2TP Tunnel Establishment
PPP Resp (UID,#PW#)
RADIUS Auth Req(UID,Token,#PW#,IA=SIDBAP)
PPP Challenge(Token)PPP Challenge(Token)
PPP Response(UID,#PW#, IA=SIDBAP)
RADIUS Auth Req(UID,Token,#PW#,IA=SIDBAP)
Auth Accept
RADIUS Accounting Req
(IP Adrs,SIDBAP)
PPP Link Est ReqPPP Link Est Req
PPP Link Est RespPPP Link Est Resp
PPP IPCP Config Req (IP Adrs)
PPP IPCP Config Resp
RADIUS Accounting Req(IP Adrs,SIDBAP)
RADIUS Accounting Resp
Auth Accept(L2TP Tunnel End Pt, Tunnel Id)
L2TP Tunnel Est Req(Tunnel Id,UID,Token,#PW#)
L2TP Tunnel Est Resp
RADIUS Accounting RespNB This example shows the case of an Intermediate Agent at the DSLAM signalling the SIDBAP and the ISP’s LNS allocating IP Addresses.
Way Forward for UK
• NICC Standard published Jan 2010 http://www.niccstandards.org.uk/files/current/ND1638%20V1.1.2.pdf?type=pdf
• New requirements on all organisations (systems development)
• Many more organisations involved to deliver 999 (not just traditional telcos but VSPs and ISPs)
• New operational components : LIS and VPC
• New interfaces for all organisations: based on international standards as far as possible (eg IETF HELD)
• Increased co-op and trust relationships between PSAP and VSP, ISP and Access networks
• NICC Work to continue : other use cases, IP PSAPs (IP end to end)