Video Conferencing: Products, and Issues with Network Bandwidth and Security
Marshall Eubanks
tme at multicasttech.com
Fri Feb 8 19:27:46 UTC 2008
Hello;
There are some things you need to think through. (I am CTO at
Iformata Communications, and this
is our core competency.)
- Point to point only, or multipoint ? Multipoint will mean MCU's.
- Webcams or professional gear (like Polycom HDX 8000 HD video) or
telepresence ? (Over
an order of magnitude of cost increase between each step.)
- Bandwidth ? - from under 384 Kbps to over 20 Mbps at each endpoint.
- and, of course, the budget, which is tightly coupled to all of the
above.
Also, are any sites ISDN only ?
On Feb 8, 2008, at 1:04 PM, Jon R. Kibler wrote:
> Hi All,
>
> I have a client that wants to implement video conferencing.
> They would like to have multiple video participants and
> collaborative whiteboards.
>
> Anyone have any experience with such products? Comments
> and/or recommendations on products?
>
> More to the point of this post... what are the network
> and security issues associated with VC? For example:
>
> -- Would it be reasonable to expect that a remote user
> on a DSL connection to be able to VPN into a WAN
> and participate?
>
Why not, if the symmetric bandwidth is (truly) there ? You may need
some QOS if the DSL has other
uses (like, say, it's in someone's home).
> -- Are most of the products multicast? If so, what are
> the security issues with multicast and will it work
> through, for example, a Cisco VPN client tunnel?
>
Basically, none of them are, except for some academic products like
VRVS or the Access Grid conferencing system.
> -- What are the typical network bandwidth requirements?
> Are they per participant based or some other basis?
>
Generally, it is static for each participant, for a given video quality.
(Typically, if one full screen is 1 Mbps at a given quality, then it
can do a
1 Mbps point to point call, a 512 Kbps half screen 3 point call, a
250 Kbps quarter screen 5 point call, etc.)
So the outbound bandwidth may decrease, but the inbound bandwidth is
roughly constant for
any number of end-points and a given quality. (You can also mix and
match,
1/2 screen for one site and 1/4 screens for two,
for example, but it doesn't change this principle).
Note that all of this multi-point stuff has to go through an MCU and
MCU bandwidth frequently
requires more thought than endpoint bandwidth. (If you have a simple
star topology, then the MCU may need
N x the endpoint bandwidth. YMMV.)
> -- What are the general security issues with VC? Can it
> be run through an IPSec tunnel or does that break it?
>
You can do IPSEC or you can do application layer encryption or even
both.
Note that firewall / NAT traversal is also frequently an issue.
Polycom sells
gear for this and it also frequently requires some thought.
> Any ideas for good sources of information? Google doesn't
> seem to provide me with much usable information when
> trying to answer these types of questions.
Hope this is useful. If you are coming to Apricot I would be glad to
talk, as I intend to
present on just this topic, for Telepresence.
Regards
Marshall
>
> THANKS!
> Jon K.
> --
> Jon R. Kibler
> Chief Technical Officer
> Advanced Systems Engineering Technology, Inc.
> Charleston, SC USA
> o: 843-849-8214
> m: 843-224-2494
>
>
>
>
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