April 1, 1998
Video Conferencing for the Enterprise
The H.323 standard is spurring interoperability between conferencing systems, forming
a base for vendors to build on.
Sidebar: Executive Summary
Sidebar: Other Products
by William Wong Video conferencing is fast evolving from an expensive, novel
interaction medium to an economical business tool for everyday use. Today' software
can bridge the gap between network-based video conferencing and ISDN-based video
conferencing, as well as provide multiuser conference support. I looked at products from
two different vendors that provide this type of service: PictureTel' LiveLAN product
line and White Pine Software' MeetingPoint Conferencing Server.
The main force driving video conferencing growth is standards and their acceptance.
(For more information, see " Conferencing: A Work in Progress," page 57, by
Claire Tristram.) The standards allow interoperability between products from different
vendors.
The video conferencing standards include the venerable H.320 ISDN-based standard, and
the newer H.323 network-based and H.324 modem-based standards. The three do not
interoperate directly, but a gateway can bridge the gap. In fact, part of the LiveLAN
product line includes an H.320-to-H.323 gateway that allows remote ISDN users to
participate in a video conference with a network-based user.
The H.32x standards make use of additional standards for audio and video codecs
(compression/decompression) that translate between captured audio and video and compressed
data streams. The same kind of codec must be used at both ends of a video conference, but
most newer packages incorporate older and newer codecs. Each codec standard has a number,
but these tend to be irrelevant to users. The difference is in the quality of compression.
A complementary standard is the T.120 series that encompasses data conferencing
(document sharing or application sharing), as well as audio and video conferencing. The
H.32x series addresses only video conferencing- data conferencing. Most video
conferencing products come with some sort of shared whiteboard or shared application
support. The ones that support the T.120 standards are usually interoperable. The T.120
standard is relatively new, so interoperability across vendors is not guaranteed, but I
found compatibility to be very good.
The ITU' Common Intermediate Form (CIF) defines video quality. CIF defines a video
resolution of 288 pixels by 352 pixels; Quarter CIF (QCIF) is 144 pixels by 176 pixels.
Many of the available video conferencing systems (including those I tested for this Lab
Notes article) support CIF and/or QCIF resolutions.
Proprietary video conferencing implementations still exist, but most new products
incorporate these as well as the standard implementation. The proprietary implementations
typically offer better performance or more features. For example, the LiveLAN client I
evaluated supports the H.323 and H.320 standards, but it also supports PictureTel'
own implementation that provides higher frame rates, and it provides more automated
connections when going through the LiveGateway to other PictureTel video conferencing
systems.
Even with the growing interest in network-based video conferencing, its acceptance is
limited by network managers' concerns. Video conferencing is a profligate user of
network utilization, easily chewing up most of the available throughput of a 10BaseT
network. Luckily, switched Ethernet and Fast Ethernet are supplanting the hub-based
Ethernet networks, so getting the necessary throughput is less of an issue.
In this article, I first take a closer look at the network management issues, and then
at some products. I' discuss LiveLAN first because it provides both the video
conferencing clients and the hardware. I' then look at MeetingPoint, which was used
in conjunction with the LiveLAN clients. As an aside, I also toyed with Microsoft'
NetMeeting; it is a good conferencing product with a price that is hard to
beat-' free, and downloadable from Microsoft' Web site, www.microsoft.com.
(For a review of NetMeeting, see " on the Internet in 10 Minutes," November
1997, page 131, by William Wong).
Although the products I examine in this Lab Notes article (and, indeed, the bulk of
video conferencing products available) run on Windows 95 and Windows NT, there are a
number of products available for other platforms. Video conferencing standards often allow
this diverse group to operate together.
NETWORK MANAGEMENT ISSUES
There are probably as many reasons not to add video conferencing as there are reasons
to add it. Video conferencing can be put in the hands of users, but without proper
management it can mushroom into a throughput-devouring monster.
High-quality video conferencing can use 384Kbytes/sec, while acceptable performance is
attainable at ISDN speeds of 128Kbytes/sec. This is a tiny fraction of even a 10BaseT
network, but four or five simultaneous conferences can significantly impact a 10BaseT
network.
There are three solutions to the problem. The first is to limit the number of
simultaneous conferences. The second is to limit the throughput used by each conference.
The third solution is to increase the available network throughput. The first two can be
addressed by using a server-based manager such as PictureTel' LiveManager, an H.323
gatekeeper that coordinates video conference calls. The third can be addressed by
replacing hubs with switches, thereby allowing higher aggregate network throughput, or by
moving to a 100BaseT network. Very large networks need to consider capacity requirements
in detail, since their backbones may need to carry hundreds of video conference calls.
In addition to throughput considerations, video conferencing products currently have
limited capabilities for tracking usage and billing users, but support for this feature is
growing. Integration with room conferencing systems will be important, even if none are
currently installed. Once companies have experimented with the technology, adding a room
conferencing system seems to be a natural growth path.
And then there' security. Video conferencing systems become more useful as the
distance between callers increases. Unfortunately, giving a remote caller access to the
network is not on the top of most network managers' priority lists. Security must be
addressed, even if video conference access is the only remote access method involved.
Security is an issue regardless of whether a call comes in through the Internet or via an
ISDN H.320 gateway. The latter tends to be rather secure, but Internet access must often
be controlled through a firewall, which may not handle video conferencing well. Giving
selective availability may not be done easily with existing firewalls and video
conferencing tools. For example, some network managers would like to use the Internet to
connect remote users and remote sites for video calls, but not allow arbitrary connections
from anywhere on the Internet.
Management of video conference servers is not a hallmark for most products. Web-based
management and SNMP support are available, though not necessarily sophisticated.
Integration with network management suites tends to be limited, but this should improve as
video conferencing becomes more mainstream.
LIVELAN
The LiveLAN 3.0 family includes the LiveLAN client, LiveManager, and LiveGateway. The
LiveLAN client application runs on Windows 95 and Windows NT. Its PCI-based audio/video
capture board comes with a digital camera and a microphone/headphone. It also includes a
data-sharing tool called LiveShare Plus.
LiveManager runs on Windows NT. It provides video conference management with optional
throughput limits.
LiveGateway is an H.320-to-H.323 gateway. It is a hardware/software combination, and it
runs on Windows NT. The hardware consists of an ISDN BRI adapter; up to four adapters are
supported in one server.
For this Lab Notes report, I installed LiveManager 3.0 and LiveGateway 3.0 on the same
Windows NT Server system. I installed the LiveLAN 3.0 client on Windows 95 workstations.
The Windows NT server was attached to the 100BaseT connection of a 3Com LinkSwitch
1000. The Windows 95 workstations used 10BaseT connections. A single LiveManager was
sufficient for my network, making installation easy. Multiple LiveManager servers can be
used for either larger networks or WANs with low-speed links; configuration in this
instance is more complex because LiveManager' control over video conference
throughput usage and the number of calls is based on the location of conference users.
The LiveManager management application can manage LiveManager services on remote
Windows NT systems. The NT system that LiveManager is running on must have a fixed IP
address, which is referenced by LiveLAN workstations.
The LiveGateway installation went smoothly, although the ISDN BRI adapter does use an
interrupt, which can be a limiting factor with today' PCs. PictureTel has a PRI ISDN
adapter that addresses this limitation; a single PRI adapter can support multiple H.320
connections while using a single interrupt. The BRI approach works best for sites that
need only one or two outside connections.
BRI line setup only required selecting the ISDN switch type; this information is
supplied by the telephone company when an ISDN line is installed. Multiple BRI adapters
are set up in a pool and allocated on a first-come-first-served basis for outgoing calls.
Incoming calls can access any H.323 client on the network. SNMP support can be enabled,
but I had to do that after LiveGateway was installed because it first requires
installation of the Windows NT SNMP support.
The next step was to install the LiveLAN workstations. The workstations can obtain
their IP address dynamically, using DHCP, since each workstation is given its own
identification number. The identification numbers are arbitrary, so for ease of
recognition, they can match the user' telephone extension. This ability to use
workstation identification numbers instead of IP addresses is a proprietary feature of
LiveLAN. It' more flexible than H.323' use of a fixed IP address, but the
LiveLAN workstation number can only be used between LiveLAN clients.
LiveLAN supports H.323, but LiveLAN' proprietary support is more extensive. For
example, a look in the address book shows that each entry has a connection type associated
with it. These include H.323, H.320 via LiveGateway, and LiveLAN connections. Local
LiveLAN connections use the workstation' identification number. Entries for a call to
a remote LiveGateway network include the LiveGateway ISDN telephone number and the
identification number of the workstation. This allows automatic connections from one
LiveLAN workstation to another, via ISDN. Incoming H.320 calls cannot use this feature,
because the H.320 standard is designed for a point-to-point connection. LiveGateway
handles H.320 calls by routing them to a designated operator station.
The workstation software' diagnostic program exercises the LiveManager and
LiveGateway connections. Audio and video information can be echoed back to the workstation
to see how this type of connection performs.
Once I had a pair of workstations configured, I was able to test the LiveLAN-to-LiveLAN
connection. This type of connection was one of the best I have seen for network-based
video conferencing systems that use a conventional network backbone. The workstation
displays only the view from the workstation or the caller' camera. The window size
can be QCIF, CIF, or full screen; QCIF and CIF work best with the H.323 and H.320
connections. In case the LiveManager server does not limit throughput, the LiveLAN client
can restrict its data transfer rate.
I set up a workstation with Microsoft NetMeeting and a third-party video capture system
to test LiveLAN' H.323 compatibility. This worked well, but I did have to know the
workstations' IP addresses. Calls could be placed in either direction. NetMeeting did
not work with LiveGateway.
LiveLAN clients required minimal configuration. The configuration that was needed
consisted primarily of updating the global address book maintained through LiveManager.
LiveManager logs were of limited use, but they can be helpful in debugging problems.
LiveGateway testing was done using an Intel ProShare Business Video system, which supports
H.320. It is comparable to PictureTel' Live200p ISDN video conference system. Calls
could be placed in either direction, although incoming calls were always directed to the
designated operator station. The operator could forward a call to a LiveLAN client or an
H.323 client.
H.323 and H.320 connections were not as clear or clean as the LiveLAN-to- LiveLAN
connections. Still, the standards-based connections proved more than adequate. LiveShare
Plus, PictureTel' whiteboard application, was usable between LiveLAN workstations.
The main limitation I encountered was that the LiveLAN client only worked with the
stock Windows 95 IP stack. Unfortunately, I had some workstations set up to use other IP
stacks. In this case, I installed Microsoft' NetMeeting on these workstations using
third-party hardware.
Once the workstations and server were thoroughly tested, White Pine' MeetingPoint
was added to the mix.
MEETINGPOINT
White Pine Software' MeetingPoint Conference Server provides multiperson video
conference support for H.323 clients, which normally provide only point-to-point
connections. MeetingPoint accepts audio and video input from an H.323 client and
broadcasts that information to other clients attached to the same conference. Figure 2 shows how MeetingPoint servers might be used in
conjuction with LiveLAN clients, LiveManager servers, and LiveGateway servers.
The MeetingPoint server can host multiple conferences, although a client can only be
attached to one conference at a time. MeetingPoint can use IP multicast, so one connection
can support a number of receiving clients, significantly reducing network bandwidth usage.
MeetingPoint servers can be linked together for coordinated conferences; this
configuration is especially useful in WAN environments when conference clients are spread
across multiple sites. In this case, a MeetingPoint conference would be set up between
MeetingPoint servers at each site with a single connection between two servers; the
servers then distribute the information to local clients, enlarging the conference.
MeetingPoint conferences are static entities that are maintained even if no client is
attached to the conference. Clients can attach and detach from a conference at any time,
and MeetingPoint' security system can limit which clients can attach to a particular
conference.
Each conference has a moderator who can control which user has the floor, which users
can send information, and which users can only view the conference. For clients like
NetMeeting and LiveLAN, which only have a single video window, the user that has the floor
is the person displayed in the window. White Pine' CU-SeeMe H.323 video conferencing
client can simultaneously display all sending clients attached to a conference.
MeetingPoint installation is straightforward. It is installed as a Windows NT service
that can display an optional log window. Web-based management is done using any late-model
Java-equipped Web browser. The MeetingPoint Web server uses a different port than a
standard Web server, which uses port 80, so MeetingPoint can be placed on a system
that' already running a Web server.
MeetingPoint' Web interface is used to add users, configure conferences, and
manage links to other MeetingPoint servers. You can control user access to conferences
based on their IP address or by user name and password; the IP address can limit a
conference to an intranet. Users must be added to the conference list individually,
although it is possible to allow a block of IP addresses to use the server. An import
option or self-registration feature would be useful.
Conference creation is a simple process of giving the conference a number and a
description, setting the maximum number of attendees, defining what features can be used
in a conference, and then selecting or configuring a server layout template. The latter is
only an issue for conferences that span multiple servers. Templates let a network
administrator handle details, such as how multicast is to be handled, so even multiple
server conferences can be set up easily. The test configuration used a single server, so
conference creation was very simple. I skipped the documentation when creating my first
conference, and I failed to note that the conference identification must be a number.
MeetingPoint' error message was a bit cryptic, forcing a thorough reading.
The MeetingPoint conferences were tested with White Pine' CU-SeeMe video
conferencing client (a demo copy was included with MeetingPoint), as well as LiveLAN and
NetMeeting clients. A Web interface provides authentication, but the video conference
client must be run after that. A Web interface for conference selection can be created by
configuring the Web server and the Web client, and creating an HTML page; however, this is
a job that should be incorporated into the MeetingPoint Web server. The documentation
allowed me to create such a page. It was well worth the effort, but it is only suitable
for conferences that stay active for a long period of time.
MeetingPoint actually consists of two conference servers: one for H.323 and one for
T.120. The two operate independently, but moderators can set up both when creating an
H.323 conference. User access is another matter; for example, NetMeeting clients must
attach separately to a T.120 and H.323 conference.
MeetingPoint only accepts incoming calls, so participants need to know when and where a
conference will be held. MeetingPoint accepted calls through LiveGateway, but only when
the security controls were relaxed (because there was no way to authenticate the incoming
caller).
MeetingPoint introduced a very minor delay because it must echo incoming information to
clients. H.323 clients impose more delay because of encoding, decoding, and network
transmission, so MeetingPoint' contribution is negligible.
MeetingPoint has basic performance and logging capabilities. It also has rudimentary
billing support, but network administrators must obtain third-party support or set up a
mechanism to process log files.
MeetingPoint works well if all clients are from the same vendor. H.323 conferences do
allow mixed clients, but T.120 conferences require the same kind of client for all
participants.
MeetingPoint' lack of scheduled meetings was a disappointment. In fact, the
existing support made it more convenient to have a conference mimic a conference room
which was then scheduled using an external application. Unfortunately, this tended to
allow anyone to drop in unexpectedly. Dynamic conference creation was possible, but it was
definitely not on par with making a three-way call on a telephone- with the most
cryptic telephone system.
Overall, MeetingPoint does what it claims. Some of its limitations are due to
limitations in the standards. Others are due to product maturity. It is possible to come
up with a whole host of wish list features, such as the ability to put up a video note
when a conference is full, but this should not detract from an otherwise worthwhile
product.
TRY IT AND SEE
Video conferencing has finally reached the point where PCs were many years ago. Falling
prices and improved performance will always make next year' products look better than
today', but the technology is practical now.
Video conferencing is not for every desktop-. Universal serial bus cameras and a
growing use of data and audio conferencing will eventually bring video conferencing to
almost every desktop.
Products like LiveLAN and MeetingPoint do work together, but there are still rough
edges. All combinations of clients and servers are not equal, which can cause problems in
a heterogeneous video conferencing environment.
The technology has advanced to the point that it' time for any company that can
benefit from video conferencing to start some trial tests or even deploy it on a small
scale.
William Wong is a computer consultant and author. You can reach him at bwong@voicenet.com.
Objective: Enhance communication and collaboration among an organization'
staff by providing video conferencing capability for intranet and remote users.
Issues: Audio and video quality. Bandwidth management. Interaction with
third-party H.323 and H.320 clients.
Products or implementation tested: PictureTel LiveLAN clients running on Windows
95. LiveManager and LiveGateway running on Windows NT Server 4.0. White Pine
Software' MeetingPoint Conference Server 3.0 running on Windows NT Server 4.0.
Advantages: LiveGateway provides integrated local H.323 and remote ISDN H.320
video conferencing support, interacts with any H.323 or H.320 clients, and supports
multiple ISDN H.320 lines (with additional ISDN adapters). MeetingPoint supports any T.120
and H.323 clients, multiple servers, multicast IP, and browser-based management.
Disadvantages: H.323 clients do not, on their own, permit multipoint
conferencing (but third-party products like MeetingPoint can be used for this). No H.324
modem gateway. LiveLAN has no video capture support. MeetingPoint offers limited group
management, no published conference schedules, and no scheduled activation/deactivation of
conferences.
Price: PictureTel LiveLAN 3.0 costs $1,195, LiveManager 3.0 costs $595,
LiveGateway 3.0 costs $2,395. MeetingPoint Conference Server 3.0 starts at $1,995 for a
10-user license.
PictureTel
100 Minuteman Rd., Andover, MA 01810
(978) 292-5000
(800) 716-6000
www.pictel.com
White Pine Software
542 Amherst St., Nashua, NH 03063
(603) 886-0903
www.wpine.com
Other vendors that offer H.323 video conferencing solutions include:
Intel
Intel Business Video Conferencing System
www.intel.com/proshare/conferencing/products/
Microsoft
NetMeeting
www.microsoft.com
White Pine Software
CU-SeeMe
www.wpine.com
