: Bit Torrent to offer DRM's video content
Russell McMahon email (remove spam text)
> I didn't find any clear information, though, whether this is true or
> Do you have any?
I had this ref to hand
More hearsay than hard info, but the P2P phrase may ring a few alarm
bells. But maybe not :-).
skype "peer to peer"
produced the interesting pages referred to below, amongst many others:
These may be somewhat surprising to many people. Even if not all 100%
correct they do rather point to things being abit different than most
people may realise. Even ignoring bandwidth usage considerations,
software that is designed to penetrate firewalls invisibly as of right
is both a 'bad corporate citizen' and a virus writers wildest dream.
Skype explains its peer to peer arrangement
Which includes this
Firewall and NAT (Network Address Translation) traversal.
Non-firewalled clients and clients on publicly routable IP addresses
are able to help NAT'ed nodes to communicate by routing calls. This
allows two clients who otherwise would not be able to communicate to
speak with each other. Because the calls are encrypted end-to-end,
proxies limit the security or privacy risk.
Likewise, only proxies with available spare resources are chosen so
that the performance for these users is not affected.
Several new techniques were also developed in order to avoid end-user
configuration of gateways and firewalls, whose non-intuitive
configuration settings typically prohibit the majority of users from
communicating successfully. In short, Skype works behind the majority
of firewalls and gateways with no special configuration.
An Experimental Study of the Skype Peer-to-Peer VoIP System
This paper presents the rst measurement study of the
Skype VoIP system. From the empirical data we have gath
ered, it is clear that Skype differs signicantly from other
peertopeer lesharing networks in several respects. Ac
tive clients show diurnal and workweek behavior analogous
to webbrowsing rather than lesharing. Stability of the su
pernode population tends to mitigate churn in the network.
Supernodes typically use little bandwidth even though they
relay VoIP and letransfer trafc in certain cases....
Using Webwasher to block Skype peer-to-peer IP-based telephony
... Skype does not use standard VoIP protocols, which makes it easy
for the software, along with any vulnerabilities or malware that may
be attached to it, to pass through the corporate firewall. Other VoIP
solutions that are used successfully and safely by corporations use
open protocols such as SIP, IAX, or H.323. Because its protocol is
proprietary, there is no way to verify Skype's own security claims.
And because Skype calls are undetectable and do not leave an audit
trail, there are significant compliance problems that several
corporations may face if they allow its use ...
The bandwidth used during file transfers or during internet telephony
can be tremendous, depending on the amount of usage--and Skype can
turn your network into a "Supernode" without your consent, using it as
a relay station for calls that do not originate or terminate on your
site. The impact on productivity is severe. The reason Skype calls
work so well is that it uses "intelligent routing," which sounds like
a good idea until you realize what that means: Skype routes calls over
the most effective path possible, leveraging available bandwidth from
users on the Skype network. Skype calls itself as a "true P2P system,"
which it describes as "one where all nodes in a network join together
dynamically to participate in traffic routing-, processing- and
bandwidth-intensive tasks that would otherwise be handled by central
servers." This means that if one person in your company is using
Skype, your bandwidth may get pressed into service by Skype to handle
the tasks that another VoIP provider would be handling on its own
servers. If your connection is used by Skype in this way, bandwidth
consumption can notably affect your network's performance. Skype
provides no option for disabling use of your resources in this way
Most interesting pdf "slide show".
Any node with a public
IP address having
sufficient CPU, memory
and network bandwidth
is a candidate to
become a super node
???? An ordinary host must
connect to a super node
and must register itself
with the Skype login
Almost an ad, but interesting.
Skype bugging your network? Here's how to squash it
... The Skype peer-to-peer protocol is designed to penetrate
firewalls: experts emphasise the potential security risks of the Skype
peer-to-peer protocol and say the use of Skype in a corporate network
significantly increases traffic volumes. One company claims to have
some tools to stop it. ...
See also: www.piclist.com/techref/displays.htm?key=video
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