Guide to Cisco Systems' VoIP Infrastructure Solution for SIP
SIP-Based Control for Legacy Infrastructure (SIP-09)
description
Transcript of SIP-Based Control for Legacy Infrastructure (SIP-09)
SIP-Based Control forLegacy Infrastructure
(SIP-09)
Mark E. Rayburn
Advanced Technology GroupCPT International Inc. Atlanta, GA
Creators of Voice Harbor™, Voice Application Hosting
Bogies
Share a real world experience SIP, not just for breakfast anymore Tips for encouraging Vendor collaboration Reinforce the value of Standards Inspire developers to innovate with SIP
SIP, the new duct tape?
Exposure to VoiceXML Hosting
The Situation
Hosted IVR Service Provider Large Scale, Carrier Class, Vendor Neutral
Hundreds of Applications Thousands of ports per application Very fast start-up or expansion requirements Multiple sites
VoiceXML gateways (for Interactive Voice Response) Connected to switching fabric via ISDN Proprietary DSP boards required
The Pain
Growth Need to scale quickly Need to add and support multiple vendors easily
Cost Need to maximize the density of all components Need to remove wasteful resources Perform “smarter” bridges (hairpin in the Switch)
Legacy Inbound Flow
SwitchPSTN
VoiceXML
Switch
Logs
DNISDNIS
CDRs
Tandem
Proprietary DNIS/URI Mapping
DNIS Synchronization Issues
Proprietary Log Format
Complex Conversion and
Data Acquisition
Application
Proprietary DSP and Network Interface Cards
Excess Resources: Switch already has DSPs
Each blind transfer used4 switch ports and 2 VoiceXML ports
: Analysis
Legacy Outbound Flow
SwitchPSTN
VoiceXML
Switch
Logs
CDRs
Service
Tandem
Internet
CPA
Application
HTTP
API
Vendor API to kick off call
Proprietary Log Format
Complex Conversion and
Data Acquisition
Proprietary DSP and Network Interface CardsExcess Resources:
Switch already has DSPs
: Analysis
Analysis Recap
Too much work for each VoiceXML Gateway Vendor
DNIS/URL Administration Train Support on new Admin interface Handle sync issues with switch database
Call record logging Understand the format Schedule data acquisition Provide data access to VoiceXML log storage Convert VoiceXML log to internal CDR format
Outdial API Convert to Customer facing UI Retain and integrate CPA, if necessary
Analysis Recap (continued)
Squeeze out excesses DSP Resources
Why have this in Switch AND VoiceXML?
Network Interfaces Buying 2 additional network interfaces (DS1) to connect
the VoiceXML gateway to the Switch
Transfers Stop using DSP board to bridge the call
Strategy: Phase the Work
Phase 1 Use SIP between Switch and VoiceXML
gateways Design “Smart” blind transfers (Switch Only) KISS Philosophy
no carrier issues all under “our roof” (more control) less interoperability and testing issues
Biggest gains – lowest risk
SIP Phase 1 Development
Develop a Switch-centric architecture Identify needs from vendors
Call Progress Analysis (CPA) – must be done using the DSPs in the switch
Need to pass URL to VoiceXML on Invite
Identify other gaps & dependencies in “other” areas Reporting, CDRs, Etc.
Phase 1 SIP Expected Benefits
Densest configuration for the Switch Doubles the capacity per chassis
Densest configuration for the VXML gateways Doubles the capacity per chassis
Eliminate the need for a DSP board in the gateway Thousands of dollars saved per DS1 Hundreds of dollars saved per gateway chassis Saves rack space, power, and cooling costs Enables blade server option for gateways
Legacy Inbound Flow
SwitchPSTN
VoiceXML
Switch
Logs
DNISDNIS
CDRs
Tandem
Application
Proprietary DSP and Network Interface Cards
Excess Resources: Switch already has DSPs
: Changes
Proprietary DNIS/URI Mapping
DNIS Synchronization Issues
Proprietary Log Format
Complex Conversion and
Data Acquisition
Each blind transfer used4 switch ports and 2 VoiceXML ports
Legacy Inbound Flow
SwitchPSTN
Switch
Logs
DNISDNIS
CDRs
Tandem
Application
: Changes
VoiceXML
SIP
SIP eliminates DSP board in VoiceXML Gateway.
DTMFs sent via RFC 2833
Proprietary DSP and Network Interface Cards
Excess Resources: Switch already has DSPs
Legacy Inbound Flow
SwitchPSTN
Switch
Logs
DNISDNIS
CDRs
Tandem
Application
: Changes
VoiceXML
SIP
Proprietary DNIS/URI Mapping
DNIS Synchronization Issues
Proprietary Log Format
Complex Conversion and
Data Acquisition
Each blind transfer used4 switch ports and 2 VoiceXML ports
Legacy Inbound Flow
SwitchPSTN
Switch
Logs
CDRs
Tandem
Application
: Changes
VoiceXML
SIP
DNIS/URL
Switch application DNIS database expanded to include starting URL.
Proprietary DNIS/URI Mapping
DNIS Synchronization Issues
SIP Invite allows passing the URL from the switch.
Legacy Inbound Flow
SwitchPSTN
Switch
Logs
CDRs
Tandem
Application
: Changes
VoiceXML
SIP Proprietary Log Format
Complex Conversion and
Data Acquisition
Each blind transfer used4 switch ports and 2 VoiceXML ports
DNIS/URL
Legacy Inbound Flow
SwitchPSTN
Switch
CDRs
Tandem
Application
: Changes
VoiceXML
SIP
DNIS/URL
Proprietary Log Format
Complex Conversion and
Data Acquisition
Switch application now drops call information directly to the CDR
database. No conversions or complex data acquisition
required.
Proprietary VoiceXML logs no longer
needed.
Legacy Inbound Flow
SwitchPSTN
Switch
CDRs
Tandem
Application
: Changes
VoiceXML
SIP
Each blind transfer used4 switch ports and 2 VoiceXML ports
DNIS/URL
Legacy Inbound Flow
SwitchPSTN
Switch
CDRs
Tandem
Application
: Changes
VoiceXML
SIP
DNIS/URL
Switch application sees the REFER and bridges the call
through the Switch and frees the VoiceXML ports for other calls.
Each blind transfer used4 switch ports and 2 VoiceXML ports
VoiceXML sends a REFER to the Switch
on a blind transfer.
SIP Phase 1 Inbound Call Flow
SwitchPSTN
VoiceXML
Switch
DNIS/URL
CDRs
Tandem
Application
SIP Invite with URL
Legacy Inbound Flow
SwitchPSTN
VoiceXML
Switch
Logs
DNISDNIS
CDRs
Tandem
Application
: BEFORE
SIP Inbound Flow
SwitchPSTN
VoiceXML
Switch
DNIS/URL
CDRs
Tandem
Application
SIP Invite with URL
: AFTER
Legacy Outbound Flow
SwitchPSTN
Switch
Logs
CDRs
Service
Tandem
Internet
CPA
Application
HTTP
API
Vendor API to kick off call
Proprietary Log Format
Complex Conversion and
Data Acquisition
Proprietary DSP and Network Interface CardsExcess Resources:
Switch already has DSPs
: ChangesSwitch to VoiceXML
gateway is now SIP
VoiceXML
Legacy Outbound Flow
SwitchPSTN
Switch
CDRs
Service
Tandem
Internet
CPA
Application
HTTP
API
Proprietary Log Format
Complex Conversion and
Data Acquisition
: Changes
VoiceXML
Switch is now writing CDRs directly, so no VoiceXML logs are
needed.
Legacy Outbound Flow
SwitchPSTN
Switch
CDRs
Service
Tandem
Internet
CPA
Application
HTTP
API
: Changes
VoiceXML
Vendor API to kick off call
Data Acquisition for CPA data
SwitchPSTN
VoiceXML
Switch
CDRs
Service
Tandem
Internet
Application
HTTP
SIP
Data Acquisition for CPA data
Vendor API to kick off callSwitch application now performing CPA, so the outdial service is the same for all VoiceXML gateways
Switch application now performing CPA, so this data can be logged
with CDR
SIP Outbound Flow : Changes
Secondary Problem Set
SIP design introduced 2 new challenges Communication of CPA info to VXML Gateway
Added an additional parameter to the INVITE message which contained the CPA information
VoiceXML gateway Vendor exposed the INVITE parameter in the VoiceXML environment
Tying application records to CDRs Used the SIP “CALL ID” header to provide a
unique, unifying field that both the Switch and VoiceXML application could access
SIP Phase 1 Outbound Call Flow
SwitchPSTN
VoiceXML
Switch
CDRs
Service
Tandem
Internet
Application
HTTP
SIP Invite with URL & CPA
Call ID exposed to Application
Legacy Outbound Flow
SwitchPSTN
Switch
Logs
CDRs
Service
Tandem
Internet
CPA
Application
HTTP
API
: BEFORE
VoiceXML
SIP Outbound Flow
SwitchPSTN
VoiceXML
Switch
CDRs
Service
Tandem
Internet
Application
HTTP
SIP Invite with URL & CPA
Call ID exposed to Application
: AFTER
Conclusions
SIP greatly simplified the architecture Reduced points of failure Reduced long term Development and Operations
SIP cut costs dramatically Density Eliminated excess resources
SIP cut time to market Provided a non-proprietary framework Easy to engage Vendors
Next Steps
SIP Phase 2 Extend the SIP transfer functionality for
more sophisticated call routing scenarios Local number presence by going SIP to
the network
Research Prototype to better understand the
interplay and associated strengths of SIP and CCXML
Questions?and/or
Discussion
THANK YOU for your
Time, Thoughts, and Attention
Feedback, suggestions, or follow up is very welcome:
What is VoiceXML?
An XML variant used to describe DTMF, Advanced Speech Recognition (ASR), and/or Text-to-Speech (TTS) applications
Based on IP and web-centric technologies Submitted to the W3C in early 2000, it is
now the preferred IVR (Interactive Voice Response)
Additional information: www.voicexml.org