Transcript What do I do?

Cisco SIP VoIP Application –
Microsoft Voice.NET
Jimmy K. Lai
Service Providers
Cisco Systems Taiwan
July 23, 2003
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
1
Agenda
• SIP Architecture Overview
• Overview of MSN Voice.NET
• Technical Challenges
• Understanding the ITSP Models
• SIP Proxy requirements
• SIP Gateway requirements
• Network Engineering requirements
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
2
SIP Basics - Architecture
Applications
Call-Control
• Can reside in end-points or
centralized servers (B2BUA)
• Can reside in end-points
or centralized servers
• Can be stateful or stateless.
• Need to be URL
addressable
• All Signaling uses SIP
• May or May Not be SIP
URLs
• Allows features to be
implemented on end-points
or servers.
SIP
SIP
PSTN
RTP
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
Legacy PBX
3
SIP Basics - Architectural Elements
Endpoints:
•
User Agent Client (UAC) / User Agent Server (UAS)
•
Originate & Terminate SIP requests
•
Typically an endpoint will have both UAC & UAS, UAC for originating
requests, and UAS for terminating requests
Servers:
•
Proxy Server
•
Redirect Server
•
Registrar Server
•
Back-to-Back User Agent (B2BUA)
Applications
Standalone
SIP Server
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
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SIP Servers/Services
Registrar
Redirect
Location
Database
SIP
Servers/
Services
“Where is this
name/phone#?”
REGISTER
“Here I am”
3xx Redirection
“They moved,
try this address”
SIP Proxy
Proxied INVITE
“I’ll handle it for
you”
INVITE
“I want to talk
to another UA
SIP User
Agents
© 2001, Cisco Systems, Inc. All rights reserved.
SIP User
Agents
Voice.NET - “ITSP in a Box”
SIP-GW
5
SIP VoIP Review - Signaling Call Flow
PSTN
PSTN
SIP VoIP Network
Calling Party
Called Party
INVITE w/ SDP
SIP Signaling
&
SDP
Signaling
(UDP or TCP)
100 Trying
180/183 Ringing w/ SDP
Signaling
200 OK
ACK
Bearer Or
Media
Media (UDP)
RTCP Stream
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
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SIP VoIP Review –
Proxy Server Signaling
PSTN
PSTN
SIP VoIP Network
Calling Party
SIP Signaling
&
SDP
Signaling
(UDP or TCP)
Media (UDP)
INVITE
100 Trying
Called Party
INVITE
100 Trying
180 Ringing
180 Ringing
200 OK
200 OK
ACK
ACK
Signaling
Bearer Or
Media
RTCP Stream
NOTE-1: Proxy Server NEVER originates signaling.
NOTE-2: Proxy Server can
be Stateless
or Transaction-Stateful
Voice.NET
- “ITSP in a Box”
© 2001, Cisco Systems, Inc. All rights reserved.
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SIP VoIP Review –
Redirect Server Signaling
PSTN
PSTN
SIP VoIP Network
INVITE
Calling Party
Called Party
3xx Redirect
SIP Signaling
&
SDP
Signaling
(UDP or TCP)
INVITE
100 Trying
180 Ringing
Signaling
200 OK
ACK
Bearer Or
Media
Media (UDP)
RTCP Stream
NOTE-1: Redirect Server NEVER originates signaling.
NOTE-2: Redirect Server can
be -Stateless
or Transaction-Stateful
Voice.NET
“ITSP in a Box”
© 2001, Cisco Systems, Inc. All rights reserved.
8
SIP VoIP Review – B2BUA Signaling
PSTN
PSTN
SIP VoIP Network
INVITE (Call-ID#1)
Calling Party
INVITE (Call-ID#2)
100 Trying
SIP Signaling
&
SDP
Signaling
(UDP or TCP)
180 Ringing
Called Party
100 Trying
180 Ringing
200 OK
200 OK
ACK
ACK
Signaling
Bearer Or
Media
Media (UDP)
RTCP Stream
NOTE-1: B2BUA does originate signaling.
NOTE-2: B2BUA
is Call-Stateful
Voice.NET
- “ITSP in a Box”
© 2001, Cisco Systems, Inc. All rights reserved.
9
Agenda
• SIP Architecture Overview
• Overview of MSN Voice.NET
• Technical Challenges
• Understanding the ITSP Models
• SIP Proxy requirements
• SIP Gateway requirements
• Network Engineering requirements
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
10
Overview of MSN Voice.NET - Phase 1
• October, 2001 - MSN Voice.NET project goes live
• MSN Messenger client will support SIP for VoIP calls
- PC to PC calls (now)
- PC to PSTN calls (now)
- PSTN to PC calls
• MSN will work with worldwide ITSPs to terminate the
VoIP calls.
• MSN will own the customers, but ITSPs own the
billing of the customers for PSTN calls.
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
11
MSN Voice.NET Architecture –
Infrastructure (High-Level)
Passport
Servers
Microsoft
SIP Proxies
Microsoft
Voice.NET
ITSP Data Center
Cisco
SIP Proxy
Servers
Cisco
VPN 5000/ 3000
DNS
Servers
ITSP POP 1
(CAS,PRI, R2)
Cisco VPN
product
Cisco
Voice Gateways
Billing/Authentication
Account
Signup
Radius
Server
Billing
Syste
m
ITSP POP 2
(SS7)
Database
SC2200
Internet
STP
ITSP IP Backbone
Cisco
Voice Gateways
MSN User
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
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MSN Voice.NET Architecture –
Call Flow (High Level)
2. MSN associates a user with their
preferred ITSP in the MSN Proxy
5. MSN Proxy forwards the SIP
messages to the ITSP Proxy
MSN
Network
Internet
Internet
SS7
ITSP
Managed
GK
Network
STP
1. MSN user selects an ITSP from
the menu for PSTN calls
MSN
SIP Proxy
MSN
4. MSN routes the call to an ITSP
Client
ITSP
SIP Proxy
SLT
STP
PSTN
IMT
ITSP - Wholesale VoIP
6. ITSP Proxy forwards call to SIPGW
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
3. MSN user dials a PSTN number
from the MSN Messenger client.
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MSN Voice.NET Architecture –
User Sign-Up
• The MSN user will select an ITSP when they sign-up
for the service.
- The lists of ITSPs is provided at this time.
- The MSN user’s preference is loaded into the MSN SIP
Proxy
- This will allow the ITSP to “advertise” on the MSN client
• MSN will provide the MSN user information to the
ITSP via an external “push” mechanism.
- MSN user information is provided by the Passport
(PUID) login service
- The PUID (Passport User ID) identifies the MSN user
- The PUID password is not provided to the ITSP
- The PUID must be used to bill the MSN user
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
14
MSN Voice.NET Architecture –
MSN Proxy Provisioning
• MSN User <-> ITSP preference will be provisioned in
the MSN SIP Proxy
- All calls from specific MSN user will go to a specific ITSP
- MSN currently doesn’t define calling areas (Regional or
International) per ITSP
• MSN will keep a list of ITSP SIP Proxy servers in their
routing tables
- Route to ITSP-A would point to proxy.itsp-a.com
- The route points to the DNS SRV record of the ITSP Proxy
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
15
MSN Voice.NET Architecture –
MSN Proxy Provisioning
ITSP Logo
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
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MSN Voice.NET Architecture –
ITSP Routing
• MSN Proxy will route PSTN calls to the ITSP SIP
Proxy servers.
• MSN will add a “Record-Route:” header to all INVITE
messages, so it sees the BYE messages.
• MSN will add a “Proxy-Authorization:” header, will
encodes the PUID in base64.
• ITSP is responsible for getting the call to the PSTN
via a SIP-GW.
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
17
MSN Voice.NET Architecture –
ITSP Branding
ITSP Status
Window
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
18
Agenda
• SIP Architecture Overview
• Overview of MSN Voice.NET
• Technical Challenges
• Understanding the ITSP Models
• SIP Proxy requirements
• SIP Gateway requirements
• Network Engineering requirements
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
19
MSN Voice.NET requirements
• ITSP must have a secure VPN connection to the MSN Network.
IPSec VPN is used.
• ITSP must provide a VoIP capable (within defined delay
budgets) network.
• ITSP must be responsible for providing the billing to the MSN
user.
• ITSP must support SIP, UDP or TCP calls.
• ITSP must support RFC2833 for DTMF-Relay.
• ITSP must support G.711 and G.723 codecs
• ITSP must be verified against the MSN “Saturn” test-lab.
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
20
MSN Voice.NET Technical Challenges
• Billing model is not explicitly defined by MSN.
- ITSP could use prepaid or postpaid
- GW must be able to support either model
• SIP-GW needed some new functionality
- RFC2833 for DTMF-Relay
- Addition for MSN-specific headers & tags
- Co-existance testing with H.323
• SIP Proxy needed some new functionality
- New RADIUS VSAs required
- Addition for MSN-specific headers
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
21
SIP Billing Models
• Billing relationships can be:
• Retail – ITSP has a direct billing relationship with
•
MSN / MSN users
Wholesale – Terminating ITSP will partner with a retail ASP
or another ITSP and bill them for total number of minutes.
ASP / partner ITSP provides subscriber billing.
• Billing model can be:
• Post-Paid – bill the MSN user at the end of the
month for total minutes used.
• Pre-Paid – deduct from a pre-paid account for minutes
used on a per call basis
• Billing collection point can be:
• Gateways – on the edge of the network
• Proxy / B2BUA - core of the network
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
22
H.323 vs. SIP Billing Differences
GK
H.225, H.245, H.323
PSTN
OGW
TGW
• RAS signaling between the GW and GK provides next-hop address resolution
• VoIP signaling is direct between GWs, so TGW can bill the call off the IP Address of OGW
Wholesale ITSP
Retail ITSP
INVITE
INVITE
INVITE
TGW
MSN User
PSTN
• SIP signaling is hop-by-hop between UAs and Proxies
• TGW knows previous-hop as upstream Proxy.
• TGW needs to look at Via:, Contact: or Record-Route headers
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
23
Possible Billing Models
• Post-Paid on the SIP Proxy (IP Side)
• Post-Paid on Egress SIP Gateway (IP Side)
• Pre-Paid on the B2BUA (IP Side)
• Pre-Paid on Egress SIP Gateways (IP Side)
• Wholesale – Retail models
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
24
Post-Paid on the SIP Proxy
Billing
System
MSN
RADIUS
Proxy
SIP
PSTN
SIP
SIP
RTP
ITSP
MSN User
In this model, the Billing Records would be generated by the Cisco SIP Proxy which resides in the ITSP
network. It would generate RADIUS Start and Stop records for each call
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
25
Possible Billing Models
• Post-Paid on the SIP Proxy (IP Side)
• Post-Paid on Egress SIP Gateway (IP Side)
• Pre-Paid on the B2BUA (IP Side)
• Pre-Paid on Egress SIP Gateways (IP Side)
• Wholesale – Retail models
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
29
Post-paid on the Egress SIP Gateway
Billing
System
MSN
RADIUS
SIP
Proxy
PSTN
SIP
SIP
RTP
ITSP
MSN User
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
30
Possible Billing Models
• Post-Paid on the SIP Proxy (IP Side)
• Post-Paid on Egress SIP Gateway (IP Side)
• Pre-Paid on the SIP B2BUA (IP Side)
• Pre-Paid on Egress SIP Gateways (IP Side)
• SIP Wholesale – Retail models
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
34
Pre-paid on the SIP B2BUA
Billing
System
MSN
RADIUS
SIP
Proxy
PSTN
SIP
SIP
B2BUA
SIP
RTP
© 2001, Cisco Systems, Inc. All rights reserved.
ITSP
Voice.NET - “ITSP in a Box”
37
Possible Billing Models
• Post-Paid on the SIP Proxy (IP Side)
• Post-Paid on Egress SIP Gateway (IP Side)
• Pre-Paid on the SIP B2BUA (IP Side)
• Pre-Paid on Egress SIP Gateways (IP Side)
- PrePaid TCL IVR scripts
• SIP Wholesale – Retail models
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
40
Pre-Paid (IP Side) on the Egress SIP
Gateways (TCL Script Timer)
Billing
System
MSN
RADIUS
SIP
Proxy
PSTN
SIP
SIP
RTP
ITSP
IP Phone
Or Softclient
“Pre- Paid” TCL-IVR Script
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
41
Possible Billing Models
• Post-Paid on the SIP Proxy (IP Side)
• Post-Paid on Egress SIP Gateway (IP Side)
• Pre-Paid on the SIP B2BUA (IP Side)
• Pre-Paid on Egress SIP Gateways (IP Side)
• SIP Wholesale – Retail models
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
45
SIP Wholesale – Retail Model
Billing
System
Wholesale ITSP
MSN
RADIUS
Proxy
SIP
SIP
SIP
SIP
RTP
Retail ITSP
PSTN
In this model Wholesaler records where the call originated from “Previous Hop” and Bills the
retailer back. This could be recorded at the Gateway or Network Proxy.
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
46
Agenda
• SIP Architecture Overview
• Overview of MSN Voice.NET
• Technical Challenges
• Understanding the ITSP Models
• SIP Proxy requirements
• SIP Gateway requirements
• Network Engineering requirements
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
47
How existing ITSPs are preparing for
MSN Voice.NET
• Expand infrastructure capabilities to
address new markets
Cisco based carriers can easily add new
protocol capabilities to the core network,
simultaneously supporting both H.323
and SIP on the Cisco gateways
SIP Client
Application SP
Call
Routing
AAA
H.323 routing information is passed from
the DGK to the Cisco SIP Proxy using
RAS messages
Billing records can be generated from the
gateways (prepaid and postpaid) and the
proxy (postpaid only)
Authentication
AAA
Billing enhancements for Windows
Messenger supported on IOS Gateways
[12.2(2)XB] and Cisco SIP Proxy Server
[Version 1.2]
Gateways are configured to handle both
SIP and H.323 traffic on a dial-peer basis
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
BILL
LRQ
Call
Routing
DGK
V
V
1408
1212
48
Agenda
• SIP Architecture Overview
• Overview of MSN Voice.NET
• Technical Challenges
• Understanding the ITSP Models
• SIP Proxy requirements
• SIP Gateway requirements
• Network Engineering requirements
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
49
ITSP SIP Proxy requirements
• Support for UDP or TCP calls
• Support for Record-Route: header
• Support for all MSN-specific headers & tags
- transport=tls in Contact: header
- tags on Record-Route: headers
- Proxy-Authorization: header
- Unknown/Unsupported codecs & attributes in the SDP
fields
• Support the ability to generate RADIUS records for
billing.
• CSPS v1.2 added support & compliance for all
aspects.
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
50
Agenda
• SIP Architecture Overview
• Overview of MSN Voice.NET
• Technical Challenges
• Understanding the ITSP Models
• SIP Proxy requirements
• SIP Gateway requirements
• Network Engineering requirements
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
51
MSN - ITSP SIP Gateway requirements
• Supports UDP or TCP calls
- Gateway can support either
• Supports RFC2833 for DTMF-Relay
• Supports MSN-specific headers & tags
- transport=tls in Contact: header
- tags on Record-Route: headers
- Proxy-Authorization: header
- Unknown/Unsupported codecs & attributes in the SDP
fields
• Supports either PrePaid or PostPaid billing models
- PrePaid via TCL-IVR scripts and RADIUS
- PostPaid via RADIUS
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
52
Agenda
• SIP Architecture Overview
• Overview of MSN Voice.NET
• Technical Challenges
• Understanding the ITSP Models
• Call Flows
• SIP Proxy requirements
• SIP Gateway requirements
• Network Engineering requirements
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
53
Network Engineering Overview
• VPN Planning:
- IPSec VPN is required between MSN and ITSP
- MSN will use either Cisco VPN3000 or VPN5000
- ITSP VPN platform requirements are not defined by MSN.
- Any compliant Cisco product could be used to terminate
the VPN tunnel
• IOS Router
• PIX
• VPN 3000/5000
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
54
Network Engineering Overview
• Capacity Planning:
- MSN has not provided Cisco with details about volume of
traffic expect to specific ITSPs
- SIP signaling bandwidth should be ~5kb per call.
• INVITE - 1000 bytes
• 100 Trying - 500 bytes
• 18x Ringing - 700 bytes
• 200 OK - 700 bytes
• ACK - 500 bytes
• BYE - 500 bytes
• 100 Trying - 500 bytes
• 200 OK - 500 bytes
- RTP is using 20ms / 24ms samples for G.711 or G.723
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
55
© 2001, Cisco Systems, Inc. All rights reserved.
Voice.NET - “ITSP in a Box”
56