What’s different about Multicast?
What if your home telephone were multicast instead of unicast?
• Anyone old enough to remember when your home phone was a “party line”?
• Anyone old enough to remember TV before cable TV & satellite TV?
– “Broadcast” to local area– cable/satellite TV kind of like “multicast”, lets you tune to a non-
local “broadcast” channel
Multicast – learn the language, acronyms, the protocols
• IGMP (v1, v2, v3) PIM, MSDP, RP, BSR• You can either become a network engineer or find some useful
tools
Some useful tools …
See if you’re on a multicast-capable networkhttp://detective.internet2.edu http://dast.nlanr.net/Projects/Beacon/
If Multicast Capable: Yes – things will likely work just fine
Do a little bit of network testing
Make sure you can get from here to there without multicast
• Detective – E2E bandwidth test• Use old-fashion tools: ping, traceroute, ftp
Try a simple multicast application• Vic, rat, sdr - http://www.openmash.org/• Listen to some multicast stream -
http://people.internet2.edu/~bdr/dvguide.html
If all this works for you – you’re ready to run ConfXP, the AG, … whatever
Is multicast a “good” thing?
Think about “bigvideo” streams:• DV/IP: 30 mbps stream, for “broadcast” events the unicast client/server model won’t scale on your network
• HDTV Compressed with MPEG2 is about 20 mbps
It’s an alternative to the MCU• Moves “session” management to the network layer• You don’t need the investment in an MCU• You (most likely) will need a “bridge”
(http://if.anu.edu.au/SW/rcbridge.html)
Access Grid – Multicast Application
provide a sense of presence, of “being there” where distributed people could interact as if they were sharing the same “room”.
using readily available collaboration technology that was affordable
integrate with existing security services and available network capabilities
Access Grid – Multicast Application
support platforms that your faculty, researchers, students were comfortable using
1. Windows XP/20002. Linux variants (RedHat, Slackware, Fedora, Debian,
…)3. Mac OS X (in the future)
support existing environments to allow people to collaborate where they are
1. Room – Shared Display, Multiple Video Streams, Single Audio Stream
2. Desktop – Desktop Monitor, Multiple Video Streams, Single Audio Stream
3. Laptop – Laptop Display, Single Video Stream, Single Audio Stream
AG looks something like this
•Large-format displays•Multiple audio and video streams•Shared applications (PowerPoint)
http://www.accessgrid.org/community/nodes/nodes.html (over 200 nodes)
ConferenceXP – Microsoft Learning Sciences & Technology Group
• “AG-like” Goals:• Single-machine architecture capable of scaling to handle large,
group-to-group-to-group conference scenarios
• Simple software installation and hardware configuration, No conference session operator is required
• Cameras, microphones and other peripherals are configured for a ‘best fit’ default configuration
• Rich, immersive collaboration environments require that audio and video streams are delivered with high quality and low latency
• Collaboration venues provide the virtual equivalent of meeting and gathering places
• A simple, configurable archival system enables individual participants to record and playback conferences
ConferenceXP Architecture
Conference API
ConferenceXP Application
Network Transport
RTDocuments API
Rtp API
Custom UI RTDocuments UI Audio/Video UI
DirectShow
RTDocumentsCapability ViewerCapability Sender
Audio/VideoCapability ViewerCapability Sender
CustomCapability ViewerCapability Sender
IETF 1889 RFP Protocol
Multicast & Unicast UDP/IP
ConferenceXP ServicesDiagnosticsArchive/PlaybackVenue Reflector/Gateway
ConferenceXP Client Provides a high bandwidth, low latency audio and visual
capability Utilizes Windows Media High Quality Audio & Video
Codec's, DirectShow, and a custom low latency networking stack (RTP).
The ConferenceXP UI is integrated The Edge, an MSR Learning Sciences and Technology project focused on building a UI for learning web services
The conferencing architecture supports:• Full screen video at 30 fps, with 250 ms latency• FireWire cameras to enable high quality, efficient video capture• Five way conferencing < 2 Mb/s
Venue Service• Provides the services necessary to create and manage
‘collaboration and learning venues’• Venue Service interfaces are exposed as Web Services
http://www.conferencexp.net
DVTS: What if you could use your HandiCam for Video Collaboration?
you could send & receive High Quality A/V• It doesn’t require funny, expensive machines• It doesn’t require involve IP issues (royalties)• It doesn’t require funny, expensive cameras• It does require a network capable of 30 mpbs
all you need is a capable Network and …• a DV capable camera (HandiCam, DVCAM, DVCPro) with
IEEE1394 (firewire) capability• DV receiver (DV Player, TV) that is firewire capable• Or an analog/digital converter(s) if using a non-firewire
capable camera/receiver
DVTS: How can I get started?
DVTS• Software encoding/decoding using the PC
processor, NIC, etc.• Runs on number of platform, though
Windows XP has the best GUI and uses PC monitor for display
• Requires a firewire card if you are a “sender” (and receiver for non-WinXP)
• Provided by DVTS Consortium & WIDE project http://www.sfc.wide.ad.jp/DVTS
CometDVIP• Hardware implementation from Fujitsu Labs• Allows a “blackbox” like device to support
DV/IP• Current video conferencing tests have been
remarkable
where does DV/IP live in the video “neighborhood”?
H.323 – How is it different?• Multicast use removes need for MCU• Higher quality, lower latency a/v streams
Access Grid – can I use it with my AG?• Current integration work underway (APAN/ANU)
MPEG2 – why not just use mpeg2?• No “IP” encumbrance, Higher quality, lower latency a/v
streams
HDTV - why not just use HDTV?• Lower latency than compressed (20mbps) HDTV stream• Lower bandwidth than uncompressed HDTV stream
“Sweet spot” – if you have the bandwidth
… in the wings … Pocket Video …
test, experiment, develop and integrate various interactive video technology on handheld devices over the Internet.
allow those who possess such devices to participate in existing collaborative sessions, such as AG, SIP, and VRVS conferencing.
exploit Handheld device capability in ways that extend the research & teaching missions of universities while taking advantage of readily available and affordable technology.
… in the wings … Pocket Video …
test, experiment, develop and integrate various interactive video technology on handheld devices over the Internet.
allow those who possess such devices to participate in existing collaborative sessions, such as AG, SIP, and VRVS conferencing.
exploit Handheld device capability in ways that extend the research & teaching missions of universities while taking advantage of readily available and affordable technology.
… in the wings … Pocket Video …
The following projects are currently proposed:explore use of AG tools on iPaq using Familiar Linux
• http://internet2.motlabs.com/ipaq/• http://familiar.handhelds.org/
explore VRVS 3.0 on iPaq under WinCE• http://www.vrvs.org/Documentation/pocketVRVSguide.html
explore Microsoft Portrait work done by Microsoft Research
• http://research.microsoft.com/~jiangli/portrait/
explore Palm Pilot resources available to support collaborative, interactive applications