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Current NarrowbandVC “Standards”
Standard H.321H.310
H.320 H.323 H.324 Hybrid
XmissionTechn.
ATM ISDN Packet POTS WANIP
A/VprocessingImplement-
ations
H/ware H/ware&
Mixed
H/ware&
S/ware
H/ware S/ware
Standards & VRVS
VRVS uses Hybrid (MBONE) “standards”– Experimental - not IETF or ITU– Need > 1GMip for 30fps– Limited use of MMX– Insufficient parallelisation– Common s/ware components are vic, rat, wbd,
(sdr)
Beginning to support H.323– For quality, need hardware DSPs
Recommendation 1
Limit investment in A/V Capture cards for ‘old’ VRVS and MBONE
Decide how scalable you want H.323Decide whether ISDN importantDecide whether investment incremental or
strategic
The ITU Standards: H.320
H.320 - < 2MBits/sec, ISDNEach ISDN channel is 64KBits/sec
– ISDN-2 = 128 KBits/sec– ISDN-6 = 384 Kbits/sec– Can also use ISDN-4 @ 256 KBits/sec– Minimum is one channel @64KBits/sec– (a good test of standards’ compliance)
For channels beyond 2, need BONDING– Mode 1 prevails for this application
The ITU Standards: H.323
Packet-basedUp to 2 Mbits/sec, adaptiveTransmission technology undefinedFR sometimes usedConsider only IP networks here
Other StandardsMbone IETF tools: sdr, vic, rat, wbd,…..H.310 & H.321 for B-ISDN (ATM)H.324 for low bit rate videotelephones……….othersT.120 - T.140 - data sharing
– ……MS NetMeeting commonest implementation– Others platform-specific
SIP (RFC2543, Mar. ‘99)
T.120
The “missing component” of VC systems
Includes whiteboarding, ftp and application
sharing
DataBeam’s FarSite most successful interim
product ….. But now swallowed up (Lotus)
Intel’s ProShare Premier a strong alternative
PictureTel had LiveShare Plus.…but no more
More T.120 Also-rans are MediaRing (Mediacom),
TALKShow (FutureLabs)Most DTVC suppliers have moved to MS
NetMeetingNetMeeting dominates at present:
– DC-Share (DataConnection)– Netopia Virtual Office (Farallon Comms.)– Timbuktu Pro (Farallon Comms.)
PictureTel (Q4/97), VCON, VTEL, Sony, Zydacron, Vis à Vis, GPT and MMT all offer NetMeeting BUT……….
What about MS NetMeeting?Implements modified T.120 stack for data
sharingDesigned to prevent interoperability with
strict T.120 implementationsSecurity risk
More about MS NetMeeting…..
Also implements H.323…….Example of a software-based codecIntel ProShare is anotherSuggestion: Do NOT use for a/v Users will ignore one-to-one restrictionsProblems in UK VIP and Megaconf.Probably banned next this yearDevelopment??
MBONE Answers to T.120wb
– Shared whiteboard, text and postscript drawings
nt– Shared text editing tool for ASCII
qb– 20% increase in remote audience participation
More tools under development….
SIP vs H.323SIP is IP exclusivelySIP less complex - cheaper to
implementSIP easier debug - text
messages/commandsSIP Client/Server arch. - security,
mg’mntSIP easier Firewall handlingSIP more scalable
Future of H.323Originally intended for LANHas come a long way for Internet useDespite slow take-up…..H.323 will persist for ~5 years or moreWill bridge with ISDN, ATM and PSTNWill integrate e/mail, voice mail, fax, call
centres, VCGSM integration underway….Too much investment to abandonStill developing…...
More on Future of H.323
2 Revisions of standardMore may be expected…..Several AnnexesAnnexe D important for HEP…..Limited implementations
H.320, H.323 and T.12*Implementations
H.320 in hardware, firmware and software -– Desktop hosts include Win98, Win2000, WinNT– No linux hosts
H.323 in hardware, firmware and software -– Desktop hosts include Win98, Win2000, WinNT– No linux yet– Some Mac - fast changing
T.12* in software– MS NetMeeting prevails, but others exist for
UNIX and esp. for WinXX
Transmission PSTN ISDN ATM
H.324 H.320 H.310 H.323
<64 KB/sec <2 MB/sec ~2 MB/sec 10 Base X nv,ivs,vic vat, rat
Intermedia Sync.? Yes H.221 Yes H.223 No (bad) Yes (good)
Congestion Handling?
No No ECD (yes) No Not yet (vic) No (ivs,nv)
Compression H.263 H.261 H.261 H.261/3Intra-261
(vic)Haar (ivs)
Comp. Implementation
Hardware h/w or s/w h/wh/ware or
s/ware
Audio G.729 CELP G.711G.722, G.728
etcG.7xx
Audio Fill? Yes Not needed Not needed CELPNo - vat
(bad)Yes - rat (good)
Examples Vivo,Granny
Intel Proshare
VCON Armada
First Virtual@ <25MB/sec
PictureTel LiveLAN
Notes nv -------------> H.261 difficult (4:2:2) ivs --------------> nv difficult (4:1:1) (Y:U:V)
Classes of VC Technology (up to ~2 MB/sec)
Implementation/Rate
VRVS
Circuit Switched Packet Switched
s/ware (vic, nv, ivs)
vat, rat, ivs
MBONE Tools
IP & ATM as carrier
Range of VC Systems
0 2 4 6 10 12 14 168
ISD
N-6
ISD
N-2
H
.323
?
Lin
e S
peed
/ Qua
lity
AT
MP
OT
S
Capture Cards/Videophones
PC DTVC
H/wired DTVC
RollaboutRoom - based
Room - basedPC DTVC
£ K
Conclusion for Desktops….
For data sharing, use NetMeeting ===> Win98, WinNT, maybe Win2000But there are problems even then…….
H.323 and Firewalls
Must have Rev. 2 complianceS’ton have tested twoAxent’s Raptor looks goodCheckPoint’s Firewall-1 appears to be OK nowEdu prices comparable, tho’ Raptor not in
CHESTCisco PIX may now be alright…..No linux recommendationsProblems with NetMeeting V2.*
Conclusions for FirewallsIf you are behind one on campus, check its
H.323 rev. 2 capability
H.323 Protocol
Stack
H.323Endpoints
H.323Gatekeeper
H.323VIU
H.323Gateway
H.323MCU
MCU Facilities
At UCL (Pete Clarke)At Edinburgh
– [email protected] or– [email protected]
Both ExperimentalNo Direct Booking!
Entry Level Recommendations 2
Use a PC with Win98 or WinNTZydacron Z353 at £995.0 + VATAugment with Polyspan SoundPoint PC at
about £80 + VATGet additional headset from supplier of Z353Make supplier responsible for integrating the
extrasUse NetMeeting V3.1Recognise the limitations
A Cheaper Entry Level OptionFor laptops, Win98 Polyspan
ViaVideo at about £400 + VATbut….
–Changing IP address….–Multiple IP addresses…..–Win2000 + X-Active + NetMeeting + ViaVideo
–Camera
Polyspan ViaVideo
An Alternative - VCON ViGO
Z353 vs ViaVideoZ353
Single PCI half-length board
ISDN-2 and IPS-Video aux inputHeadset, camera micsAux. Line outWin98, WinNT,
Win2000Suitable for rollabout PC£995 + VAT
ViaVideoExternal USB
connection IP onlyNo auxiliary inputsBuilt-in mic onlyUses audio out in PCNo WinNT support
Portable to e.g. ‘plane£~400 + VAT
A Scalable AlternativeZydacron Z360 costs ~ £1,500Single full length PCI boardFor ISDN, also need ZC206 @ £1,750Buy together for £2,995 + VATCapable of TV output, SVideo aux. Input
– So two cameras or document camera
Auxiliary mic. Input tooAux. Line output tooBuilt-in echo cancellation
Echo Cancellation - A Superb Multiway
Solution?
Queries?
Next edition of “Recommendations” late Spring– Will include mid-range and some high-end
recommendations
Information on cameras, doc. Cameras, other add-ons
Queries to [email protected]
