SIP – dealing with SIP – dealing with early adulthood early adulthood
Henning SchulzrinneColumbia University
SIP 2004 – January 2004Paris, France
(Early) Adulthood(Early) Adulthood
“fully developed and mature” Not quite yet, but no longer a
teenager probably need another 6 years to be
grown up… Responsibilities:
Dealing with elderly relatives POTS Financial issues payments, RADIUS Family emergencies 911
OverviewOverview SIP in 2003
Standardization – a long, hard slog Filling in the product palette
finally, cheap phones VoIP (and SIP) over Wi-Fi (802.11) Real deployments
commercial (wireless, consumer, enterprise) Internet2
SIP as a brand: SIPphone, SIPura, SIPquest, SIPCPE, … SIP in 2004
Large-scale consumer usage How much regulation for VoIP? Emergency calling
Major RFCs publishedMajor RFCs published Security mechanism agreement (RFC 3329)
negotiate algorithms with next hop Requirements for resource priority (RFC 3487)
prioritization of calls in military networks and emergencies
REFER method (RFC 3515) call transfer
DHCPv6 for SIP (RFC 3319) automatic outbound proxy configuration
Proxy-to-proxy extensions for PacketCable (RFC 3603)
Symmetric response routing (RFC 3581) improved NAT interaction
Major RFCs publishedMajor RFCs published Service route discovery (RFC 3806)
REGISTER returns “preloaded route” to be used by UA for services SIP and SDP compression (RFC 3485/3486)
compress SIP headers and body via dynamic dictionary Call flows (RFC 3665/3666; actually 2004…)
explain behavior by example useful for testing common cases not a spec replacement
Summary: except for REFER, mostly relevant to subsets of SIP developer community PacketCable 3G Military, emergency response
RFCs in the pipelineRFCs in the pipeline Ready & done, but typically
waiting for normative references Examples:
message waiting indication caller preferences user agent capabilities ENUM for SIP H.323 interworking requirements presence – CPIM, watcher info, …
When are we going to get When are we going to get there?there? In 2003, 6 SIP + 2 SIPPING RFCs published In 2002, 14 SIP + 4 SIPPING RFCs Currently, 24 SIP + 25 SIPPING + 18
SIMPLE WG Internet Drafts does not count individual drafts likely to be
“promoted” to WG status The .com consultant linear extrapolation
technique®
pessimist 8.5 more years if no new work is added to the queue
optimist 4 more years
SIP is PBX/Centrex readySIP is PBX/Centrex readycall waiting/multiple calls
RFC 3261
hold RFC 3264
transfer RFC 3515/Replaces
conference RFC 3261/callee caps
message waiting message summary package
call forward RFC 3261
call park RFC 3515/Replaces
call pickup Replaces
do not disturb RFC 3261
call coverage RFC 3261
from Rohan Mahy’s VON Fall 2003 talk
simultaneous ringing
RFC 3261
basic shared lines
dialog/reg. package
barge-in Join
“Take” Replaces
Shared-line “privacy”
dialog package
divert to admin RFC 3261
intercom URI convention
auto attendant RFC 3261/2833
attendant console
dialog package
night service RFC 3261
centr
ex-s
tyle
featu
res
boss/admin features
attendant features
SIP, SIPPING & SIMPLE –00 draftsSIP, SIPPING & SIMPLE –00 drafts
0
10
20
30
40
50
60
70
1999 2000 2001 2002 2003
SIPSIPPINGSIMPLE
includes draft-ietf-*-00 and draft-personal-*-00
What’s left to do in What’s left to do in SIPPING?SIPPING? Highlights for flavor SIPPING
automated configuration of end systems instead of the current hodge-podge of tftp and HTTP
servers KPML for stimulus control (complements RTP-based) request history: where has this request been and what
was it doing there? SIP-to-QSIG protocol translation end-to-middle security early media: media prior to call completion (enhanced
ringback) conferences
What’s left to do in SIP?What’s left to do in SIP? Call leg manipulation: Replaces, Join headers SIP MIB, 2nd edition SIP over SCTP transport Authenticated identity body (AIB) Globally routable user agent URIs (GRUU)
create new addressable SIP entities on the fly
What’s left – SIMPLEWhat’s left – SIMPLE IM & presence is not a protocol, but an eco system
manage authorizations manage watcher lists selective authorization and content customization need to do equivalent of SMTP + IMAP/POP + ACAP all at
once components in progress:
presence event package meta-events: not user, but system changes event filtering partial notification data element manipulation (XCAP)
manipulate watcher lists and authorization unified approach with GEOPRIV (geo-information authorization)
rich presence
SIP-based conferencesSIP-based conferences Multicast and simple dial-in/dial-out
conferences supported within SIP But need control infrastructure:
access lists (authorization) media mixing topology conference events
users joining and leaving sidebars and similar partial conferences floor control mid-session control of video codecs
Does not strongly depend on signaling protocol IETF XCON working group
but still may use SIP event mechanisms
SIP products beyond $600 office SIP products beyond $600 office phonesphones
Finally, basic IP phones below $100
802.11 phones video conferencing speakerphones $85
SIP product buzzword of the SIP product buzzword of the yearyear Softswitch fading…
need new VC-suitable buzzword
Session border controller as Swiss army knife for today’s broken Internet:
QoS enforcement typically, manages
DiffServ TOS bits NAT control (inbound
calls) IP-IP application-specific
interconnect accounting and statistics
But don’t play nice with encrypted SIP bodies
often weird hybrid of packet inspector, proxy and B2BUA
802.11 + VoIP802.11 + VoIP Most home phones are
cordless phones Homes have multiple phone
plugs, but one broadband access point
Mobile users in warehouses, hospitals, on campuses, …
often, no cell phone coverage Thus, interest in both 802.11-
only and cell 802.11 hand-off
But 802.11 capacity is much smaller than advertised for small (VoIP) packets
channel acquisition time Significant inter-AP hand-off
delays
?
Transition to broadbandTransition to broadband Numbers still small, but moving beyond
exploratory trials to real deployments November 2003: 38% of U.S. home Internet
users connect via broadband (Nielsen/NetRatings)
SIP deployments – landlineSIP deployments – landline Consumer broadband:
Vonage (90,000 lines), Packet8, … buckets of minutes or unlimited long-distance
SIP invisible, but it just works Time-Warner: “Time Warner Cable, the second-largest US
cable group, will [in 2004] roll out a national internet-based telephone service.”
AT&T: “The long-distance giant plans to offer VoIP-enabled services to 1 million consumers in the next two years, beginning with a roll-out in major cities across the U.S. in the first quarter of 2004.”
Verizon MCI Advantage (for business) Focused on hosted SIP services, rather than just SIP
termination Few midsize-to-large companies still considering
traditional circuit-switched PBX for replacement
SIP deployments – wirelessSIP deployments – wireless Usage for controlling new push-to-talk
services not user-visible, but may emerge from
hiding first step to presence-enabled voice services
Sprint PCS Readylink service “first commercial deployment of SIP by a
wireless carrier” 3G (R5) services much slower in coming
Deployment example: Deployment example: SIP.eduSIP.edu Deploy SIP and VoIP across Internet2
educational institutions Transition E.164 SIP URIs But don’t wait for VoIP end system
deployment
“+1-617-637-8562, come here. I need you!”
(from slides by Ben Teitelbaum)
A. G. Bell did not say:
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 SIP.edu Architecture (Phase 1)(Phase 1)
© Ben Teitelbaum, with permission
DNS
INVITE (sip:[email protected])DNS SRV query
sip.udp.bigu.edu
bigu.edu
SIP User Agent
SIP.edu Architecture SIP.edu Architecture (Phase 2)(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
© Ben Teitelbaum, with permission
SIP.edu growthSIP.edu growth
http://voip.internet2.edu/SIP.edu/
e.g., sip:[email protected] +1 212 939 7042
Other Internet2 SIP-related Other Internet2 SIP-related effortsefforts Voice disaster recovery for higher-
education community in times of regional or national crisis
principle: two of everything, geographically distributed
inbound and outbound PSTN interworking
College Park, MD & Boston, MA proxies:
primary node at MAX/Georgetown University secondary node at Texas A&M
SIP phones as emergency endpoints
Redundancy modelRedundancy modelSelf Healing
Network Technologies
Redundant BroadWorks
Call ProcessingNodes
Redundant GatewaySwitching
Nodes
HSRP
OSPF IGP
eBGP
RedundantSwitches
RedundantRouters
LAN LAN
DNSSRV
© Internet2, with permission
Internet2 disaster Internet2 disaster recoveryrecovery
Virginia
GU/MAX
Network Gateway
I2
SIP-PRI
Boston
Network Gateway
SIP-PRI
TAMU
PSTN
LAN LAN
from “Disaster Recovery VoIP Trial”, September 2003© Internet2, with permission
Challenges for 2004Challenges for 2004 Completing SIP IM + presence system Regulation
can no longer claim that this is just a toy Emergency calling
easy if local gateway manageable for fixed devices painful in general case redesign of emergency calling
system see talk on Friday
Continued network fragmentation “out-of-box” experience still painful
configuring port forwarding or having another proxy in the DSL modem
Skype (Kazaa) capitalized on NAT traversal dicey network reliability
PSTN regulationPSTN regulation Goals of POTS regulation
ensure competition (Telecommunications Act of 1996) VoIP enhances
ensure customer QoS mainly repairs and reliability, not transmission quality
emergency calling (911, 112) CALEA (lawful intercept) universal service fund
Details differ, but goals in other countries likely similar Staved off regulation for 5 years, but incumbents, states and
communities are getting worried Phone bills are a major tax user fee collection mechanism
school taxes 911 taxes state excise taxes (2.5%) federal taxes (6.5%) …
Universal service fund Universal service fund (US)(US) Universal service
fund high-cost support low-income support rural health care schools and libraries
(E-Rate) 8.7% of interstate Hard to argue with
police departments, rural health clinics and librarians
Purpose 2004 est. (M$)
Schools and libraries
2,046
Rural health care 58
High-Cost 3,223
Low income 653
Total 5,982
ConclusionConclusion SIP standardization moving into clean-up phase
but need continuing contribution now that the exciting pieces are done…
SIMPLE needs to wrap up initial suite, soon competition by XMPP and others
Major deployments starting or on near-term horizon conditions met:
stable protocol version 2 of most products range of CPE options and price points
2004 to be dominated by solving operational problems:
large-scale multi-vendor enterprise deployments provide direction in regulation hopefully,
minimalist