Re: FW: Skype allowance

[Cal Frye <cjf () CALFRYE COM>]

Martin Radford wrote:
> Skype for Business is supplied as an MSI and can be managed by Group
> Policy, according to their site.  Their Guide for Network
> Administrators can be found here:
> <http://www.skype.com/security/guide-for-network-admins-30beta.pdf>
Thanks, Martin, for pointing me to this. Quoting page 9:

"And although supernodes need to accept a relatively small number of
directory entries, they do not actually carry content: voice, text,
video, or file-transfer data. Supernodes are restricted from using more
than 5 kilobits per second of bandwidth."

"A relay host is similar to a supernode but is [sic] has a different
role and purpose in the Skype network. While each supernode functions as
temporary directory index server for nearby peer nodes in the cluster, a
relay hosts [sic] acts as data transfer /relay/ station by connecting
Skype clients that are unable to connect directly with one another."

"Relay hosts /do/ carry Skype network traffic but they have strict
limits in terms of how much bandwidth they can consume on a per-session
basis. Note also, that while in theory a relay host can carry more than
one relayed session, in practice this is uncommon..."

This clarifies what I've seen watching our Language Lab folks use Skype.
Some computers create a few hundred separate flows, but don't consume
substantial bandwidth in the process. I believe at least a few of these
I've watched were /not/ supernodes, but those individuals had several
dozen buddies in their directory, and the tiny but numerous flows relate
to checking the online status of all those contacts in the buddy list. I
have not seen much trouble, either with overall bandwidth or Skype
traffic, that I could blame on either supernodes or relay hosts on my
campus. I feel some of these fears have been overblown.

--
Regards,
-- Cal Frye, Network Administrator, Oberlin College

   www.calfrye.com,  www.pitalabs.com

"When everything comes your way, you're in the wrong lane."