1. CS 479R Telecommunications
UVSC CS 479R -- Telecommunications and Voice over IP -- Lecture 4
CS 479R Telecommunications
VoIP Issues
Gary D. Brown, Guest Lecturer
Lecture 4
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues
(C) Gary D. Brown

2. UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues
Introduction
SS7 Network Architecture
SS7 Protocols
SS7 Call Signaling
VoIP Issues
VoIP NG 9-1-1
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

3. UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues
CALEA (Wiretapping)
LNP (Local Number Portability)
Government Regulations
Taxes
E911 (Emergency Services)
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

4. UVSC CS 479R – Telecommunications and Voice Over IP
CALEA
Communication Assistance for Law Enforcement Act
Lawful interception of telecommunications
“Wiretap” law
Wire-line/Wireless Network Compliance
Required for CO and MSC switches
Not applicable to tandem switches
VoIP Network
Required of all VoIP Service Providers
Consumers can use any VoIP gateway or service anywhere at anytime
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

5. UVSC CS 479R – Telecommunications and Voice Over IP
CALEA
Wire-line/Wireless Network Implementation
Must reserve switch ports (trunks) for wiretap recording devices
Wiretap recording devices may be remotely located
Must transmit both sides of voice conversation to wiretap recording device
Caller/called party must be unaware
Switch software must enable electronic wiretap
By Calling Line Identification (CLI)
By Destination Number
By Authorization Code or PIN (DTMF tone entry)
Must handle call forwarding and record redirection information
Must record call waiting and 3-way calling information
Must record call signaling information and link to recording
Call signaling information must be searchable
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

6. UVSC CS 479R – Telecommunications and Voice Over IP
CALEA
VoIP Network Implementation
Must reserve DSP resources for wiretap recording devices
Up to five (5) simultaneous real-time RTP streams to remote IP-based wiretap recording devices (may be in different IP networks)
Must transmit both sides of voice conversation to wiretap devices
Caller/called party must be unaware
VoIP call server/proxy software must enable electronic wiretap
By Calling Line Identification (CLI), SIP URI or H.323 address
By Destination telephone number, SIP URI or H.323 address
By Authorization Code or PIN (DTMF tone entry)
Must handle call forwarding and record redirection information
Must record call waiting and 3-way calling
Must record call signaling information and transmit within 8 seconds
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

7. UVSC CS 479R – Telecommunications and Voice Over IP
CALEA
Lawful Intercept
Requires court order (subpoena)
Must identify target (CLI, destination, authorization code, SIP URI, H.323 address, etc.)
Must be signed by judge and delivered by constable or other peace officer
Telecommunications Service Provider must follow its CALEA compliance procedures to implement
Must have documented CALEA compliance plan with detailed procedures
Must document procedure execution
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

8. UVSC CS 479R – Telecommunications and Voice Over IP
CALEA
Telecommunications Service Provider Compliance
All CO/MSC switches—compliance deadlines of October 25, 1998 and June 30, 2002 (extension request grants)
VoIP Service Providers deadline of June 30, 2006
All Telecommunications Service Providers by April 7, 2007
Must have documented CALEA compliance plan with procedures
Employees must be trained in compliance procedures
Must fill out and submit “Flexible Deployment Assistance Guide Template” ( to
FBI’s CALEA – Flexible Deployment Assistance Guide 4th Edition (May 2004)
OMB Control Number: (expiration date 4/30/2007)
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

9. UVSC CS 479R – Telecommunications and Voice Over IP
CALEA
Telecommunication Device Manufacturers
Wire-line/Wireless devices
ANSI/J-STD-025-A-2003 (April 2003)
Available on online store
VoIP devices
ASN.1 modules for SIP and H.323
FBI’s Electronic Surveillance Needs for Carrier-Grade Voice over Packet (CGVoP) Service (Issue 1 dated January 29, 2003)
“U.S. Government Restricted—For Official Use Only”
Special handling and control requirements
Must be requested from FBI—cannot be legally obtained from any other source
Is available on several Internet websites
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

10. Local Number Portability (LNP)
Applies to all Telecommunication Service Providers (TSPs)
Wire-line, Wireless and VoIP
Allows consumer to keep telephone number when changing carriers and even technology
Old carrier “ports out”
New carrier “ports in”
Carriers use an LNP service bureau to effect change between them
Service bureau interfaces with each carrier’s Operational Support System (OSS)
Original LNP was for “local” numbers only
Competitive Local Exchange Carriers (CLECs)
Now “Number Portability” but often still referred to as “LNP”
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

11. Local Number Portability (WNP)
Internally-routed “Routing Number” (SS7 term)
Landline Implementation (LNP)
SS7 Service Control Point (SCP) database lookup
Access carrier’s internal network switches use Routing Number to route call to “owner” carrier for call original or termination
Wireless Implementation (WNP)
Wireless “MDN” (Mobile Dialed Number)
Remains with subscriber
Wireless “MSID” (Mobile Station ID)
Changes when porting to different carrier
May be automatically or manually programmed in phone
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

12. Government Regulations
Telecommunication Service Providers (TSPs)
Wire-line and Wireless Service Providers
Resellers and MVNOs (wireless)
VoIP Service Providers (VSPs)
FCC ruled VoIP services are “interstate in nature” and not subject to state regulation
Federal Regulations (all TSPs)
“214” Carrier Registration
Universal Service Fund Contributor
National “Do Not Call” Registry (wireless only)
FCC Prepaid Card Service Provider Certification
State Regulations (not applicable to VSPs)
State Registrations (59)
State Universal Service Fund(s)
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

13. UVSC CS 479R – Telecommunications and Voice Over IP
Federal Taxes
Federal Universal Service Fund “Contribution”
Interstate services only
Contribution rate set quarterly
Current quarter (1Q2008) rate is 10.2%
Next quarter (2Q2008) rate is 11.3%
Quarterly FCC Form 499Q (estimate)
Annual FCC Form 499A (actual)
Monthly Invoice
All TSPs including VSPs
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

14. UVSC CS 479R – Telecommunications and Voice Over IP
Federal Taxes
Federal Local Number Portability Tax
Paid by all TSPs
Funds all local number porting expenses of all carriers
Currently % of TSP’s annual revenue
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

15. UVSC CS 479R – Telecommunications and Voice Over IP
State Taxes
State Universal Service Fund Tax
Intrastate services only
Wire-line and wireless only
Vary from state to state
Utah (0.9%)
California has five (5) USF taxes each with rates 0.2% to ~2.5%
New York has no USF tax
State E911 Tax
State Poison Control Tax
State Sales Tax
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

16. UVSC CS 479R – Telecommunications and Voice Over IP
County/City Taxes
E911 Tax
Franchise Tax
Sales Tax
Special Service District Tax
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

17. UVSC CS 479R – Telecommunications and Voice Over IP
E911 Emergency Services
Basic 911
Original Emergency Services
Landline only
Telephone number displayed to emergency operator
Could not dispatch if caller could not speak
Problem for dispatchers was (and still is) location of caller
E911
“Enhanced” Emergency Services
Operator display shows
Telephone number
Address
Guaranteed emergency personnel response even if caller cannot communicate
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

18. Wire-line E911 Architecture
PSTN
Tandem CO
Selective Router
ALI
Public Safety Answering Point (PSAP)
ALI Automatic Location Identification Database
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

19. UVSC CS 479R – Telecommunications and Voice Over IP
Wire-line E911 Call Flow
Caller dials “9-1-1”
CO switch routes call [via tandem switch] to “Selective Router”
Selective Router routes call based on caller’s telephone number to appropriate Public Safety Answering Point (PSAP) responsible for caller’s Emergency Services Zone (ESZ)
PSAP queries Automatic Location Identification (ALI) database for address using caller’s telephone number
ALI returns address to PSAP
Telephone number and address displayed on PSAP dispatcher screen
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

20. Wireless E911 Emergency Services
Mobile E911
Problem #1 – “I can hear you now, but where are you?”
Problem #2 – Cell phone mobility and roaming (not in home area)
Phone GPS Method
Phone contains built-in GPS receiver and sends latitude and longitude coordinates
3 satellites for latitude/longitude and 4 satellites for lat/long/altitude
Location accuracy convergence with multiple satellite signals takes time
2.5 minutes per satellite
GPS does not work inside metal enclosures or under water-covered structures or vegetation
Network Triangulation Method
MNO estimates location using signal’s “angle-of-arrival” at cell tower antenna for direction and phone’s power level for distance
Accurate to 500 meter radius
Multiple cell tower triangulation increases location estimation accuracy
Accurate to 200 meter radius
PSAP must request of Mobile Network Operator at time of call
Poor emergency response if caller cannot speak (need address!)
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

21. Wireless E911 Architecture
PSTN
Tandem CO
Selective Router
MSC
MPC
Wireless Network
ALI
Public Safety Answering Point (PSAP)
ALI Automatic Location Identification Database
GIS Geographic Information System
MPC Mobile Positioning Center
GIS
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

22. UVSC CS 479R – Telecommunications and Voice Over IP
Wireless E911 Call Flow
Caller dials “9-1-1” and presses “Send”
MSC switch passes MDN, MSID and location information to Mobile Positioning Center (MPC)
MPC sends caller’s latitude/longitude to a Geographic Information System (GIS)
GIS uses latitude/longitude to determine and return civic address and applicable Emergency Services Zone (ESZ)
MPC returns an Emergency Services Routing Key for the ESZ to the MSC (ESRK is a 10-digit E.164 number pre-assigned to a particular ESZ)
MSC routes call [via tandem switch] to “Selective Router”
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

23. UVSC CS 479R – Telecommunications and Voice Over IP
Wireless E911 Call Flow
Selective Router routes call to PSAP responsible for ESZ using ESRK
PSAP queries ALI database for caller’s location address using ESRK
ALI looks up ESRK, finds [pre-configured] “wireless shell” record for MPC, and sends ESRK to MPC
MPC uses ESRK to find and return caller’s address
ALI returns caller’s address to PSAP
MDN and address displayed on PSAP dispatcher screen
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

24. VoIP E911 Emergency Services
Problem #1 – “I can hear you, but where are you?”
Currently no way to locate physical address of IP devices
Problem #2 – VoIP device mobility
Dynamic IP address assignment
VoIP users must register location of VoIP device
U.S. government required 95% customer registration by Nov 28, 2005
Non-attainment required VoIP Service Provider (VSP) to cut off non-registered customers (since rescinded)
VoIP devices can be moved without re-registration
Emergency services personnel sent to wrong location
VSP’s have many E911 disclaimers
Current VoIP E911 uses E-2 interface made for wireless
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

25. Wireless E911 Architecture
PSTN
IP Network
ESGW
Selective Router
Tandem
VPC
VSP
Public Safety Answering Point (PSAP)
ALI Automatic Location Identification Database
ERDB Emergency [Services] Routing Database
ESGW Emergency Services Gateway
LIS Location Information Server
VPC VoIP Positioning Center
VSP VoIP Service Provider
ERDB
ALI
LIS
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

26. UVSC CS 479R – Telecommunications and Voice Over IP
VoIP E911 Call Flow
Caller dials “9-1-1” on VoIP device
VoIP device sends IP call signaling information to VSP
VSP passes IP call information to VoIP Positioning Center (VPC)
VPC queries the Location Information Server (LIS) for caller’s registered location information
LIS returns address to VPC
VPC sends address to Emergency [Services] Routing Database (ERDB)
ERDB (a GIS system) locates applicable ESZ and returns an Emergency Service Routing Number (ESRN) and Emergency Service Number (PSAP) to the VPC
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

27. UVSC CS 479R – Telecommunications and Voice Over IP
VoIP E911 Call Flow
Based on ESRN/ESN, the VPC allocates an Emergency Services Query Key (ESQK) from a pool of pre-allocated and pre-configured 10-digit E.164 numbers
VPC may optionally assign a temporary Callback Number (CBN) if the VoIP device does not have an E.164 number assignment
VPC sends ESRN and ESQK to VSP
Using ESRN, VSP routes call to Emergency Services Gateway (ESGW)
VoIP device establishes RTP session with ESGW
ESGW routes call with ESQK (as CLI) and ESRN (as destination) to Selective Router (SR)
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

28. UVSC CS 479R – Telecommunications and Voice Over IP
VoIP E911 Call Flow
Selective Router routes call to PSAP responsible for ESZ using ESQK
PSAP queries ALI database for caller’s location address using ESQK
ALI looks up ESQK, finds [pre-configured] “VoIP shell” record for VPC, and sends ESQK to VPC
VPC uses ESQK to find and return caller’s address and CBN and the VSP’s 24x7 contact information
ALI returns caller’s address and CBN to PSAP
CBN and address displayed on PSAP dispatcher screen
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues

29. VoIP Issues Next lecture on VoIP NG 9-1-1
© Gary D. Brown
UVSC CS 479R – Telecommunications and Voice Over IP
VoIP Issues