Visual Communication Development Kits
for Business Application Integration
Esa Vitikainen
Master’s thesis presentation 5.9.2006
Thesis supervisor: Prof. Östergård
Communications Laboratory
Helsinki University of Technology
Introduction
• Quality visual communication to every desk
-> Find best technology & provider
• How to get to every desk?
– useful/fun, affordable, easy, working
– personal, mobile, cross the borders
– culture >--> visual, online, on-stage
• Visual communication <> video conference
Contents
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Introduction
Multimedia communication architectures
Multimedia connectivity in IP networks
Requirements for the development kit
Development kits available
Conclusions
Real-time multimedia
communication architectures
• H.323
• SIP
• Megaco / H.248
• Comparison
H.323
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‘Packet-based multimedia communications systems’
ITU-T: 1996 v1, 2000 v4, 2006 v6; backward compatible
Entities: Terminal, gatekeeper, gateway, MCU
Closely related to respective ISDN/PSTN/ATM specs
Main function: Tight session control, compatibility
SIP
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‘Session Initiation Protocol’
IETF: 1996 draft, 1999 v2, 2002 RFC3261
Entities: User Agent, proxy / location / redirect server
text-based transaction protocol (~HTTP/SMTP) for
initiating interactive sessions of any type between users
• Main functions: Location, invitation, negotiation
SIP principles:
• End-to-end services
• Generally applicable
features
• Simplicity
• Reuse
Megaco / H.248
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Media gateway / Device control protocols
IETF & al: 1998-99 -> MGCP; IETF & ITU: 2000 H.248
Entities: dumb Media Gateways, smart MG Controller
Main function: Gateway decomposition
Architecture comparison
H.323
SIP
Megaco/H.248
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Top-down
Complete
Structured
Control
Tight
Compatible
Endpoint
centric
Bottom-up
Modular
Messy
Initiation
Loose
Extensible
Endpoint
centric
• Future:
MS / IMS / NGN
Top-down
Complete
Decomposition
Network devices
No endpoint
functionality
• Protocol
independent
media services
Architecture comparison
H.323
SIP
Megaco/H.248
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Top-down
Complete
Structured
Control
Tight
Compatible
Endpoint
centric
Bottom-up
Modular
Messy
Initiation
Loose
Extensible
Endpoint
centric
• Future:
Top-down
Complete
Decomposition
Network devices
No endpoint
functionality
• Protocol
independent
media services
MS / IMS / NGN
SHOULD complement each other.
Winner unresolved.
Real-time multimedia
connectivity in IP networks
• Barriers
– NAT, FW, Intrusion Prevention System
– Effect on each architecture
• Solutions
– FW traversal
• Enablers
– Naming / numbering scheme
– Directories, presence
• Summary
Connectivity barriers
• Symmetric NAT
– arbitrary public transport address for each connection
– > pinhole opening from inside FW impossible
• Intrusion Prevention System
– dynamic NAT/FW/filtering behaviour
Connectivity solutions
3 behavioral traversal solution categories found:
Learning
Instructing
Tunneling
• STUN ->
TURN ->
ICE (IETF)
• UPnP (industr.)
• MIDCOM, NSIS
(IETF)
• H.460.17-19 (ITU)
• SBCs, proxies,
other proprietary
Connectivity solutions
3 behavioral traversal solution categories found:
Learning
Instructing
Tunneling
• STUN ->
TURN ->
ICE (IETF)
• UPnP (industr.)
• MIDCOM, NSIS
(IETF)
• H.460.17-19 (ITU)
• SBCs, proxies,
other proprietary
+ economical
- deployment
- UPnP scalability
+ long-term, safe
- far-away, cost
- H.460 only H.323
- others non-std.
- HW cost
+ simple, ready
Small advantage: SIP. Smart ICE coming up.
Requirements for the
development kit
Integration
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compatibility
network
software only
user admin
licensing
cost
provisioning
billing
H.323 must, SIP plus
IP + GWs, traversal plus, ISDN nice
Windows must, Java/Mac/Linux plus
LDAP (MS AD)
flexible: buy-out ... usage based
feature/capability dependent
GK
GK
Requirements for the
development kit
Integration
•
•
•
•
•
•
•
•
compatibility
network
software only
user admin
licensing
cost
provisioning
billing
H.323 must, SIP plus
IP + GWs, traversal plus, ISDN nice
Windows must, Java/Mac/Linux plus
LDAP (MS AD), GK
flexible: buy-out ... usage based, GK
feature/capability dependent
GK
GK
Requirements for the
development kit
Functionality, standards
• visual
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audio
presentation
multipoint
security
extensibility
25 fps, CIF, 1 Mbps, camera ctrl
(720p, 2 Mbps)
7 kHz (14/20 kHz)
H.239 screen sharing (T.120)
4CIF receive, DTMF
H.235
(H.460.x GEF for Presence + IM)
Software development kits available
fulfilling H.323 IP Windows LDAP
VCON (Emblaze)
• IL, 1% share,
line of losses,
SW focus
• COM+GUI
• client mode
• symmetric
• 720p receive
• flex licensing
Polycom
• US, 40% share,
well profitable,
HW focus
• COM
• SIP, UPnP
• no camera ctrl
• GK port conflict
• less CPU load
OpenH323/OPAL
• AU, open source,
non-profit (consult),
small team
• DLL, low-level
• few codecs
• H.460 extensibility
• no management
• minimal encryption
Software development kits available
fulfilling H.323 IP Windows LDAP
VCON (Emblaze)
• IL, 1% share,
line of losses,
SW focus
• COM+GUI
• client mode
• symmetric
• 720p receive
• flex licensing
Polycom
• US, 40% share,
well profitable,
HW focus
• COM
• SIP, UPnP
• no camera ctrl
• GK port conflict
• less CPU load
OpenH323/OPAL
• AU, open source,
non-profit (consult),
small team
• DLL, low-level
• few codecs
• H.460 extensibility
• no management
• minimal encryption
Technical advantage: VCON (small).
Business/political/financial factors rule.
Conclusions
• Current business market requires H.323
• Tunneling only way between organizations
• 2 providers technically close, other factors
decisive
• SIP will take over; look for dual or
converged protocol/philosophy support