1. Brian Gracely Technical Marketing Engineer
Voice over IP (VoIP)
Brian Gracely
Technical Marketing Engineer

2. Agenda
Why VoIP?
Comparing & Understanding the VoIP Protocols - H Skinny MGCP SIP
SIP Tutorial
Sample VoIP Applications
Cisco VoIP products

3. Why VoIP? The Interesting Stuff
Telecommunications Act of Deregulation of the Bell networks - Open the competitive markets for Service Providers
Converged Networks Voice, Video & Data over an IP network - Reduced the costs of managing parallel networks - Allows voice to be an IP “application”
Centralized or distributed architectures - Add features where they are needed

4. Why VoIP? The Challenging Stuff
Do we need to replicate all the existing PSTN / PBX features?
What’s the right architecture? Centralized Distributed Mix of both
How do we? Provide better than PSTN QoS - Provide Admission Control - Secure the signaling & media - Meet all the regulatory requirements

5. Open Packet Telephony Open Service Application Layer
(JAIN, AIN, TAPI, JTAPI, XML etc.)
TDM/ Circuit Switch
Open/Standard Interface
Switching Network
Line
Concentration
Call Control
Connection Control
Features
Open Call Control Layer
(SIP, H.323, MGCP, etc.)
Digital Trunk
Subsystem
Common Channel
Signaling Complex
Administration
Maintenance
Billing
Open/Standard Interface
Standards-Based
Packet Infrastructure Layer
(IP, ATM)

6. AVVID Architecture - Open Packet Telephony
Collaboration
IP IVR, IP AA Apps Engine
Intelligent Contact Manager
ICM
Applications
Cisco Unity
Voice Mail, UMS
Video
Voice Portal
Call Processing
Call
Processing GK
Directory
PSTN
PSTN gateways
Analog phone support
DSP farms IP
Network
Infrastructure
Clients
IP SoftPhone
The World Is Now Global— All Apps Must Travel Time and Distance

7. Agenda
Why VoIP?
Comparing & Understanding the VoIP Protocols - H Skinny MGCP SIP
SIP Tutorial
Sample VoIP Applications
Cisco VoIP products

8. VoIP Signaling Protocols
H ITU standard, ISDN-based, distributed topology %+ of all Service Provider VoIP networks - The current interconnect for CallManager to Service Providers - Useful for video applications
Skinny Centralized Call-Control architecture CallManager controls all features over 700,000 IP Phones deployed
MGCP IETF RFC Centralized Call-Control Architecture - Call-Agents (MGC) & Gateways (MG)
SIP IETF RFC Distributed Call-Control Used for more than VoIP…SIMPLE: Instant Messaging / Presence

9. Basic H.323 Call IP Network Gatekeeper A Gatekeeper B LRQ LCF ACF ACF
RRQ/RCF
RRQ/RCF
ARQ
H.225 (Q.931) Setup
ARQ V V
H.225 (Q.931) Alert and Connect
H.245
RTP
Gateway A
Gateway B
Phone A
Phone B

10. Basic Skinny Call IP WAN PSTN Cisco CallManager H.323/MGCP Gateway
Voice Mail Server
Call Setup
Cisco CallManager
IP WAN
E.164 Lookup
Ring Back
Ring
RTP Stream
Off Hook
H.323/MGCP Gateway
PSTN

11. MGCP Architectures & Mixed Protocols
SCP
PSTN Gateway
SIP or H.323 Network
BTS / VSC
SS7
SIP
H.323 P S T N
IMT V GK
PSTN
PRI V V
Access
Gateway
MGCP
RTP
SIP / H.323

12. Agenda Why VoIP? How does it work & why is it interesting?
Comparing & Understanding the VoIP Protocols - H Skinny MGCP SIP
SIP Tutorial
Sample VoIP Applications
Cisco VoIP products

13. Why are we talking about SIP?
Cisco has never met a protocol it didn’t like…. - Customers haven’t chosen 1 protocol to define VoIP
SIP is a very Internet friendly protocol, and Cisco likes Internet friendly stuff… SIP reuses a lot of Internet protocols & formatting
Customers still weary about proprietary protocols…. - Skinny works well, but it is proprietary
It’s about the Applications!! The next “Killer App” is the integration of voice, data, video, IM & Presence… SIP can do this.
Microsoft!! 250 millions desktops might speak SIP soon…. - SIP client will be added to WindowsXP in October

14. The history of SIP
Session Initiation Protocol (SIP) is defined via RFC2543 on March 17, 1999.
Additional “feature” drafts have been written to address issues which concern SS7/ISUP handling, QoS, Alerting, DHCP, 3PCC, Firewalls & NAT, etc…
IETF SIP-WG created in September, 1999
RFC2543bis (additions) created in April 2000.
Vendor interoperability testing done at the semi-annual SIP Bakeoff (8th in August in UK)

15. The various flavors of SIP
RFC “vanilla” SIP the most commonly deployed & developed by commercial vendors
SIP-T inter Call Agent (MGC) protocol for carrying SS7 / ISUP messaging basically maps ISUP messaging to a MIME attachment
SIP extension from PacketCable additions to Security, QoS & Privacy areas

16. SIP Basics - Architecture
NTELL
GENT
SERV
CES
Application
Services
3pcc
CPL
LDAP
CPL
Oracle
XML
SIP Proxy, Registrar
& Redirect Servers
SIP
SIP
SIP
PSTN
SIP User
Agents (UA)
CAS or PRI
RTP
(Media)
Legacy PBX

17. SIP Basics - Architectural Elements
Clients: SIP Phones, Softphones, Gateways, Media Gateway Controllers, PDAs, Robots 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

18. SIP Servers/Services (cont)
LocationDatabase
Registrar
Redirect
“Where is this
name/phone#?”
3xx Redirection
“They moved,
try this address”
REGISTER
“Here I am”
SIP Proxy
Proxied INVITE
“I’ll handle it for you”
INVITE
“I want to talk
to another UA
SIP User
Agents
SIP User
Agents
SIP-GW

19. SIP Methods Consists of Requests and Responses
Requests (unless mentioned, each has a response) • REGISTER: UA registers with Registrar Server • INVITE: request from a UAC to initiate a session • ACK: confirms receipt of a final response to INVITE • BYE: sent by either side to end a call • CANCEL: sent to end a call not yet connected • OPTIONS: sent to query capabilities outside of SDP
Newly Adopted Methods: • SUBSCRIBE & NOTIFY: used to identify device status / presence. The foundation of SIP IM / Presence (IMPP). • INFO: a means of carrying “data” in a message body • REFER: the mechanism to initiate a Transfer • MESSAGE: the means of carrying “data” for SIP IMPP
Messages contain SIP Headers and Body. Body might be SDP or an attachment or some other application

20. SIP Addressing
Modeled after mailto URLs. May be a combination of FQDNs or E.164 numbers or both.
Support for Fully-Qualified Domain Names (FQDNs) using sip: URLs - sip: “John Doe”
Support for E.164 addresses - user=phone
Support for mixed addresses - user=phone
Support for E.164 addresses using tel: URLs - tel:

21. Basic SIP Call-Flow SIP UA1 SIP UA2
INVITE w/ SDP for Media Negotiation
100 Trying
180/183 Ringing w/ SDP for Media Negotiation
MEDIA
200 OK
ACK
MEDIA
BYE
200 OK

22. Basic SIP Functionality - Call Forking
“Contact
and
Location Database
INVITE
“Where is
INVITE
Proxy / Redirect
Server
INVITE
INVITE
Forked Calls can be in parallel or sequential. The first phone to answer will get the call, the others will get a CANCEL from the Proxy Server.
LOCAL PSTN

23. Basic SIP Functionality - Call Redirection
Location Database
“Where is
“You need to contact ”
Proxy / Redirect
Server
INVITE
3xx Moved
Contact:
INVITE
LOCAL PSTN
The user at informed the network
that he could be reached on his cell-phone at
National PSTN

24. 3rd-Party Call-Control (3pcc) & Back-to-Back UserAgent (B2BUA)
A user could manage their communications via a webpage. The webpage would invoke the SIP 3PCC application to create SIP sessions to all parties involved.
HTTP post
SIP Controller - 3pcc Application
INVITE sip:1234 w/o SDP
INVITE sip: w/ SDP of SIP Phone
18x / 200 OK w/ SDP
18x / 200 OK w/ SDP
ACK w/ SDP of SIP Gateway
x1234
LOCAL PSTN

25. Agenda Why VoIP? How does it work & why is it interesting?
Comparing & Understanding the VoIP Protocols - H Skinny MGCP SIP
SIP Tutorial
Sample VoIP Applications
Cisco VoIP products

26. Application Engine Architecture
External Services
Packaged Solutions
Application Toolkit
IP IVR
Voice Portal
Auto Attendant
VXML services
Unity
Telephony
Queuing
ICM
Directory Access
DB Access
Notification Services
Queuing (ACD)
Personalized Apps
Customer Apps
LDAP
Notification Server
Web Access
Paging
Enterprise Database
Web Pages

27. IP Phone Display Applications
IP Telephony Appliance
- Corporate directory integration via LDAP
- Web site integration via XML
- Personalized menu’s via softkeys
Extensible interface with IP services offers clear differentiation to PBX connected devices *

28. Convergence:Presence Services
Managing your communications
through web browsers, Instant Messaging
and mobile devices

29. Informal Agent Queuing (IAQ)
Central Site
Distribution Groups with Queuing for Resources
2 Types of Queues
Requestor
Servicer
IAQ
Server IP
SoftPhone
PSTN
Branch Agents
IP Phones
Remote Agents

30. Web Attendant Ubiquitous access via a browser
Extension look-up via LDAP
Easy of use with drag and drop interface
Benefits:
Eliminates specialized receptionist phones
Access via URL
Included with Call Manager 3.0(tbd)

31. Press #1 to Hear Stock Quote
Voice Portal Solution
IP IVR
Stock Quote
IP Intranet
Extracts XML information from web page into IP IVR
Benefit
Only one place to configure and maintain data
Consistency
Lower admin costs
Press #1 to Hear Stock Quote *

32. VXML Interpreter Context Implementation Platform
VoiceXML
Architectural
Model:
VXML Interpreter Context
Document
Server
VXML Interpreter
Implementation Platform
VoiceXML in IOS:
HTTP
Server
PSTN
RTSP
Server
Cisco
Voice Gateway

33. Agenda Why VoIP? How does it work & why is it interesting?
Comparing & Understanding the VoIP Protocols - H Skinny MGCP SIP
SIP Tutorial
VoIP Applications
Cisco VoIP products

34. Cisco VoIP Products
Call-Processing Cisco CallManager Multimedia Conference Mgr - H.323 Gatekeeper / Proxy - Cisco SIP Proxy Server (CSPS) BTS10200 Softswitch VSC3000 Softswitch
VoIP Gateways Low End: ATA 186, 827v4, CVA122, uBR924, 1750, VG Mid Range: 3810, 2421, 2600, 3600, Cat4000, AS5300, 7200, High End: AS5350, AS5400, Cat6000, AS5850, MGX8850
IP Phones , 7940, 7960, 7935, Softphone
Applications Unity UM, Personal Assistant, Conference Connection, IP IVR, IP Contact Center, Web Attendant, XML / BTXML on IP Phones EcoSystem partners
Cisco Infrastructure IOS QoS features, Line-Powered Catalyst Switches, Catalyst QoS features Application Layer Gateway (ALG) in IOS-NAT / Firewall, PIX

35. Questions?
Q&A

36. Brian Gracely - bgracely@cisco.com
Voice over IP (VoIP)
Brian Gracely -

37. Presentation_ID
© 2001, Cisco Systems, Inc. All rights reserved. 37