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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.323
➤Decide whether ISDN important
➤Decide whether investment incremental or strategic
The ITU Standards: H.320
➤H.320 - < 2MBits/sec, ISDN
➤Each 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-based
➤Up to 2 Mbits/sec, adaptive
➤Transmission technology undefined
➤FR sometimes used
➤Consider only IP networks here
Other Standards➤Mbone IETF tools: sdr, vic, rat, wbd,…..
➤H.310 & H.321 for B-ISDN (ATM)
➤H.324 for low bit rate videotelephones
➤……….others
➤T.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 NetMeeting
➤NetMeeting 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
sharing
➤Designed to prevent interoperability with strict T.120 implementations
➤Security risk
More about MS NetMeeting… ..➤Also implements H.323…….
➤Example of a software-based codec
➤Intel ProShare is another
➤Suggestion: Do NOT use for a/v
➤Users will ignore one-to-one restrictions
➤Problems in UK VIP and Megaconf.
➤Probably banned next this year
➤Development??
MBONE Answers to T.120➤wb
–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.323➤SIP is IP exclusively
➤SIP less complex - cheaper to implement
➤SIP easier debug - text messages/commands
➤SIP Client/Server arch. - security, mg’mnt
➤SIP easier Firewall handling
➤SIP more scalable
Future of H.323➤Originally intended for LAN
➤Has come a long way for Internet use
➤Despite slow take-up…..
➤H.323 will persist for ~5 years or more
➤Will bridge with ISDN, ATM and PSTN
➤Will integrate e/mail, voice mail, fax, call centres, VC
➤GSM integration underway….
➤Too much investment to abandon
➤Still developing…...
More on Future of H.323
➤2 Revisions of standard
➤More may be expected…..
➤Several Annexes
➤Annexe 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 Win2000
➤But there are problems even then…….
H.323 and Firewalls
➤Must have Rev. 2 compliance
➤S’ton have tested two
➤Axent’s Raptor looks good
➤CheckPoint’s Firewall-1 appears to be OK now
➤Edu prices comparable, tho’ Raptor not in CHEST
➤Cisco PIX may now be alright…..
➤No linux recommendations
➤Problems with NetMeeting V2.*
Conclusions for Firewalls
➤If 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 Experimental
➤No Direct Booking!
Entry Level Recommendations 2➤Use a PC with Win98 or WinNT
➤Zydacron Z353 at £995.0 + VAT
➤Augment with Polyspan SoundPoint PC at about £80 + VAT
➤Get additional headset from supplier of Z353
➤Make supplier responsible for integrating the extras
➤Use NetMeeting V3.1
➤Recognise the limitations
A Cheaper Entry Level Option➤For laptops, Win98 Polyspan
ViaVideo at about £400 + VAT
➤but….–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 IP
➤S-Video aux input
➤Headset, camera mics
➤Aux. Line out
➤Win98, WinNT, Win2000
➤Suitable for rollabout PC
➤£995 + VAT
ViaVideo
➤External USB connection
➤IP only
➤No auxiliary inputs
➤Built-in mic only
➤Uses audio out in PC
➤No WinNT support
➤Portable to e.g. ‘plane
➤£~400 + VAT
A Scalable Alternative➤Zydacron Z360 costs ~ £1,500
➤Single full length PCI board
➤For ISDN, also need ZC206 @ £1,750
➤Buy together for £2,995 + VAT
➤Capable of TV output, SVideo aux. Input–So two cameras or document camera
➤Auxiliary mic. Input too
➤Aux. Line output too
➤Built-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]
