Upload
jasmine-fitzpatrick
View
215
Download
1
Tags:
Embed Size (px)
Citation preview
22 July 2003
Internet2, Connectivity, and Advanced Interpersonal Communications
Ben Teitelbaum <[email protected]>
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Outline
Better Voice Through IP
A Look Back Over Our Shoulders
Connectivity is Key
What Internet2 Brings to the Table
Some Guiding Principles
New Internet2 Voice Activities
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
The Opportunity
Voice has been and will be a “killer app” for a long, long time
• Per-capita, daily US land-line use: 45 minutes• Per-capita, daily US wireless use: 16 minutes• Overall, per-capita minutes continue to grow
Let’s make it better!• Fidelity• Privacy• Addressing• Mobility• Survivability • Presence
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Better Voice Through IP: Fidelity & Privacy
Fidelity• Why chop off voice at 4kHz? Most power is under
4kHz, but wideband definitely improves intelligibility and comfort.
• Also, we have two of these marvelous sensory organs! – Synthetic spatial placement of audio conference participants?
Privacy• Calls over the PSTN may be encrypted, but it’s easier with VoIP• “Phones” are already general purpose computers• Users are likely to have the public keys of their correspondents in
their computing environment for other reasons (secure email, IM)
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Better Voice Through IP: Addressing
Addressing• Users should not be burdened with device addresses, when it’s people they really care about
• Addresses should be mnemonic and empower enterprises to manage the identities of their users–sip:[email protected]
• It’s time to put E.164 phonenumbers behind us!
• A.G. Bell did not say: “+1-212-637-8562, come here. I need you!”
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Better Voice Through IP: Mobility
Mobility• Not just spatial mobility (as with a cell phone)• Also, device mobility
–Users are known by one address regardless of which devices or media they use
• Also, media mobility –Seamless gatewaying between media types–For example: voice ↔ IM
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Better Voice Through IP: Survivability
Survivability• PSTN has vulnerable single points of failure
–Central office (CO) and local loop
• Internet –Designed to heal
• Though route stability and convergence times could be better
–Can handle much higher call volumes• Packet level multiplexing and adaptive, loss tolerant codecs• Highly scalable, fault tolerant signalling built from commodity PCs
–Gradual degradation of voice quality, rather than call blocking is what you want in an emergency
• Combining VoIP and PSTN results in better voice survivability than either architecture can deliver alone
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Better Voice Through IP: Presence
Presence• “Notification of events that facilitate communication” (Henning Schulzrinne)
–“On-line”, “Away”, “Idle”, “On phone”, “Out to lunch”, ...
• Back to the future–Remember: finger, write, who?–Presence restores the sense of community that existed on
timesharing systems
• Forward to the future–New standards for interoperability and scalability–User-controlled policies to provide custom views to watchers–Richer state semantics and automatic triggers
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Rich Presence
Automatic notification from many sources…
• Location beacons • Facial recognition systems• Phones• Calendar• …
Not all watchers are human• Software agents may watch
presence and route/initiate calls appropriately (e.g. below)
Watch and initiate a voice conference when everyone is available
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Presence as Glue*
presence
text --------------------- image ------------------- voice
instant messaging
directories
calendaring
video
3G cellular
conferencing
soft/hard phones
voice mail
* This slide courtesy of Jeremy George
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
So What Will the Future Look Like?
Although preceding “Better Voice Through IP” slides illustrate some potentially fruitful directions, I really haven’t a clue what the future holds!
Before setting out to nurture innovative new IP voice applications, it’s useful to consider the history of earlier communications technologies…
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Early History of the Telephone
For the first 30 years of the telephone, promoters struggled to identify the killer application that would promote its wide adoption by home owners and businesses. At first the telephone was promoted as a replacement for the telegraph, allowing businesses to send messages more easily and without an operator. Telephone promoters in the early years touted the telephone as a new service to broadcast news, concerts, church services, weather reports, etc. Industry journals publicized inventive uses of the telephone such as sales by telephone, consulting with doctors, ordering groceries over the telephone, listening to school lectures and even long distance Christian Science healing! The concept that someone would buy the telephone to chat was simply inconceivable at that time.
C. Fischer, America Calling (paraphrased by Bill St Arnaud)
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Other Earlier Communications Technologies
Email• The popularity of email was not foreseen by the ARPANET's
planners. Roberts had not included electronic mail in the original blueprint for the network. In fact, in 1967 he had called the ability to send messages between users “not an important motivation for a network of scientific computers” . . . . Why then was the popularity of email such a surprise? One answer is that it represented a radical shift in the ARPANET's identity and purpose. The rationale for building the network had focused on providing access to computers rather than to people.
J. Abbate, Inventing the Internet
Peer-to-peer file sharing• Again, not foreseen• Internet2 connectivity + directory services (Napster, etc.)
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
And the Moral Is…
Business and technology leaders…• …have a poor track record of predicting how new communications technologies will be used
• …tend to underestimate social or seemingly “frivolous” uses of new technologies and overestimate the importance of content
Users are highly motivated to communicate with each other, if only they can connect
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Connectivity is Key
Network connectivity• Can connections be established between communicating IP
addresses with high-performance and high-availability?
Application connectivity• Do devices and applications have good network connectivity?• Are there protocols and call routing infrastructure to establish
connections between communing applications?
User connectivity• Can I
reach you?
Address
Presence
Address
Presence
Application Connectivity
Network ConnectivityApp
lica
tion A
pplica
tion
(call and presence routing)
(high-performance, end-to-end IP transit)
Use
r Use
r
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
What Internet2 Brings to the Table
Eager adopters• ~4 million students• Strong institutional commitments to advance IP communications and promote collaborative apps
Connectivity• Great networking connectivity
–High-bandwidth, low-loss, low-jitter –End-to-end transparency (few NATs)–IPv6 and multicast too!
• We are committed to advancing higher-level connectivity
26% of college students use IM (twice the rate of average Internet users)*
* The Internet Goes to College, Pew Internet and American Life Project report, Sept. 2002.
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Internet2 Voice: Guiding Principles
Voice Can Be Advanced• Many ways to make voice better
– fidelity, privacy, addressing, mobility, survivability, presence
• Internet2 VoIP is not about cheap phone calls!
Connectivity First, New Services Later• Innovation occurs at the edge, but requires connectivity• Good network connectivity not sufficient• Also need application-layer connectivity and (ultimately) user-layer connectivity
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Several New Internet2 Activities
SIP.edu• Leader: Dennis Baron <[email protected]>
Presence and Integrated Communications WG•Chair: Jeremy George <[email protected]>
Voice survivability• Leader: Chris Peabody <[email protected]>
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
SIP.edu
Goals• Grow SIP connectivity in Internet2• Increase value proposition for end-user SIP adoption• Promote convergence of voice and email identity• Low entry-cost means for campuses to...
–Provide a useful service–Get their feet wet with SIP
Means• Publishing “cookbook” with several alternative “recipes”• Obtaining corporate sponsorship and promotional pricing
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
SIPProxy
DNSSIP-PBXGateway
PBX
INVITE (sip:[email protected])
INVITE(sip:[email protected])
DNS SRV query sip.udp.bigu.edu
telephoneNumberwhere mail=”bob”
PRI / CASbigu.edu
CampusDirectory
SIP User Agent
Bob's Phone
SIP.edu Architecture (Phase 1)
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
DNS
INVITE (sip:[email protected])DNS SRV query
sip.udp.bigu.edu
bigu.edu
SIP User Agent
SIP.edu Architecture (Phase 2)
locationDB
If Bob has registered, ring his SIP phone; Else, call his extension through the PBX.
REGISTER(Contact: 207.75.164.131)
INVITE (sip:[email protected])
SIPProxy
SIPRegistrar
Bob's SIP Phone
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Presence and Integrated Communications
Newly chartered “PIC” working group
Foci• Presence• Instant messaging• Integrated communications
First-year Deliverables• Rich Presence and Integrated Communications Demonstration (Internet2 Member Meeting, Fall 2003)
• Engineering and management-level tutorials (Spring 2004)
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
Voice Survivability
Broadsoft/PAETEC/Georgetown Trial • SIP-based voice disaster recovery trial• Emergency phones on GU campus• Redundant Broadworks server nodes• Redundant PAETEC gateways in separate COs
Voice survivability and disaster recovery is increasingly a big deal for Internet2 schools
• Other projects in this area are anticipated
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
For More Information
Voice Over IP Working Group• http://voip.internet2.edu/
Presence and Integrated Communications WG • http://pic.internet2.edu/
Great SIP tutorial• http://www.iptel.org/sip/
Other sources• J. Abbate, Inventing the Internet, MIT Press, Cambridge, Mass., 1999.• C.S. Fischer, America Calling: A Social History of the Telephone to
1940, University of California Press, Berkeley, 1992.• A. Odlyzko, Content is Not King, First Monday, Vol. 6, No. 2, 2001.
www.internet2.edu
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
SIP Attributes
Component protocol that provides • User registration and mobility• Call routing, setup, tear down, and redirection
Makes heavy use of existing standards• SDP • RTP • MIME • DNS • UDP • TRIP
Easy and familiar feel• Textual encoding • Email-style headers • HTTP-style error codes •
URL addresses
Signaling and media paths separate• Signaling through servers for mobility and call services• Media on direct path for low RTT
www.internet2.edu“Inernet2, Connectivity, and Advanced Interpersonal Communications”
SIP Components
User Agent (UA)• Hard or soft phones that initiate and receive calls• Media to exchange is negotiated P2P between UAs
Registrar Server• Authenticates and accepts registration requests from UAs• Maintains location DB binding user to one or more registered UAs
Proxy Server• Routes calls (possibly through a chain of proxies) to UA• Keeps no session state (for scalability)
Redirect Server• Replies to calling UA with a redirect
Server functionality is typically bundled