Re: Video Conferencing: Products, and Issues with Network Bandwidth and Security

[Marshall Eubanks <tme () multicasttech com>]

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
>
>
>
>
> ==================================================
> Filtered by: TRUSTEM.COM's Email Filtering Service
> http://www.trustem.com/
> No Spam. No Viruses. Just Good Clean Email.