Carrier Use of SIP
Aparna Vemuri
Voice Engineering Architect
Level 3 Communications
Eric Zimmerer
Director of Product Management
ipVerse Inc.
Vemuri,
Zimmerer,
1
Network Architecture
SS7
Network
Softswitch
SS7
Network
Softswitch
SIP BCP-T
MGCP
Circuit
Switch
Circuit
Switch
IP/ATM Network
Home/SOHO
Enterprise
Trunking
Gateway
Trunking
Gateway
RTP
Vemuri,
Zimmerer,
2
Network Architecture
 SIP with additions = Softswitch to Softswitch
 Open Standards (SIP BCP-T)
 Isolate legacy signaling and Maintain backward
compatibility
 Enable scalable deployment of Softswitch network
Vemuri,
Zimmerer,
3
SIP BCP-T
 SIP: Session Initiation Protocol RFC 2543
 INFO Method
 ISUP MIME Type
 ISUP – SIP Mapping
 NAP Architecture
Vemuri,
Zimmerer,
4
SIP Session Initiation Protocol
 IETF Standards track: RFC 2543
 Simple: Set up and tear down sessions
 Wide acceptance
 Stack commercially available
Vemuri,
Zimmerer,
5
INFO method
 Session initiation and teardown is not enough
 Mid-Call events
 More complex services enabled
Vemuri,
Zimmerer,
6
ISUP MIME Type
 Standard method of encapsulating legacy signaling
 Simplifies Inter-working:


Local variant
Interconnect variant (LCD)
 Specific target: do one thing well
Vemuri,
Zimmerer,
7
Why not use ISUP?
 Which ISUP?
 Build Tomorrow’s network with Yesterday’s
protocol?
 SIP BCP-T isolates legacy signaling problems
 New services develop faster with IP protocols
Vemuri,
Zimmerer,
8
ISUP SIP mapping
 Use SIP as a basic function or tool
 Build applications that use SIP for call setup
 Remember: SIP is not ISUP
Vemuri,
Zimmerer,
9
NAP architecture
 Interconnect Packet Networks



Circuit to packet origination
Packet to packet NAP
Packet to circuit termination
 Security!
Vemuri,
Zimmerer,
10
Network Access Point
ipVerse
Control Switch
SS7
Network
SS7
Network
Softswitch
SIP BCP-T
MGCP
NAP
Circuit
Switch
IP/ATM
Network
IP/ATM
Network
Enterprise
Circuit
Switch
Trunking
Gateway
RTP
Vemuri,
Zimmerer,
Home/SOHO
Trunking
Gateway
11
MGC to SIP end user device
 Tremendous power in distributing intelligence
 Software development at Network Edge

Homebrew PBX
 Incorporation of Apps in the Network
 Security!
Vemuri,
Zimmerer,
12
Intelligence at the Edge
SS7
Network
ipVerse
Control Switch
SS7
Network
Softswitch
SIP BCP-T
Circuit
Switch
Circuit
Switch
IP/ATM Network
Home/SOHO
Enterprise
Trunking
Gateway
Trunking
Gateway
Vemuri,
Zimmerer,
13
Summary
 SIP BCP-T: Open standard for Softswitch to
Softswitch Communication
 Isolate Legacy Signaling and Maintain
Backward Compatibility
 Build Scalable Softswitch Networks
Vemuri,
Zimmerer,
14
Proven Interoperability
SS7
Network
ipVerse
Control Switch
SS7
Network
Lucent
Softswitch
SIP BCP-T
MGCP
Circuit
Switch
Circuit
Switch
IP/ATM Network
Home/SOHO
Enterprise
Trunking
Gateway
Trunking
Gateway
RTP
Vemuri,
Zimmerer,
15