Skype and LAN traffic

The_Techie

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If two PCs are connected to the same router on the LAN and both are signed into Skype, would a call between the two use LAN traffic only, instead of internet traffic?
 
that's not possible. Skype needs to connect to their server on the internet, to make a call. So, if you sign in to your skype on your PC, it connects to their server on the internet. Now, when you mate, in the other room, connects to skype, his skype again connects to their server, it doesn't connect to your server.

In the same way, calls have to go from your own PC, via the ADSL / 3G / ISDN / iBurst modem / router to their server, and then onto the user name that you "phoned", regardless of where that user is. Thus, if you phone your mate, on the same internet connection, you both connect to the remote server and transmit data to & from the remote server.
 
skype IS p2p, but cant do jack without contacting a supernode, which acts as a traffic relay between the two skype clients.

no machine that is using NAT will ever be nominated as a supernode.
aka, that rules out 99% of machines on a local lan.
so skype calls between two clients on a local lan WILL go out via the internet and still chew bandwidth.

to do what you want to do, without using internet bandwidth, use something like microsoft portrait
http://research.microsoft.com/mcom/portrait/
 
Aag Please...
Have you actually tested it or not?

The question was:
"If two PCs are connected to the same router on the LAN and both are signed into Skype, would a call between the two use LAN traffic only, instead of internet traffic?"

This would imply the the LAN is being NATed and Firewalled using the same PUBLIC IP. This means that the 2 Skype clients are using the same PUBLIC IP and different LOCAL IPs. Why would skype route traffic via their own servers if it is coming from the same PUBLIC IP?

The initial call-setup traffic travels directly to the SKype servers. This is mostly to determine if the other Skype users is online and WHERE that client is. After that initial chatter the actual call is handled by the two skype clients themselves. That means to handle the call themselves they will route the call via the LAN since they are using the same PUBLIC IP but different LOCAL IPs.

We can speculate all day long, but the point is: I tested it (more than once) and it does use the LAN for the actual voice traffic and the WAN to do the signalling traffic (In very much the same way as the SIP protocol works)
 
Try dragging a huge file into the other local persons Skype Window and see how fast it transfers. That should answer your question.
 
Aag Please...
Have you actually tested it or not?

The question was:
"If two PCs are connected to the same router on the LAN and both are signed into Skype, would a call between the two use LAN traffic only, instead of internet traffic?"

This would imply the the LAN is being NATed and Firewalled using the same PUBLIC IP. This means that the 2 Skype clients are using the same PUBLIC IP and different LOCAL IPs. Why would skype route traffic via their own servers if it is coming from the same PUBLIC IP?

The initial call-setup traffic travels directly to the SKype servers. This is mostly to determine if the other Skype users is online and WHERE that client is. After that initial chatter the actual call is handled by the two skype clients themselves. That means to handle the call themselves they will route the call via the LAN since they are using the same PUBLIC IP but different LOCAL IPs.

We can speculate all day long, but the point is: I tested it (more than once) and it does use the LAN for the actual voice traffic and the WAN to do the signalling traffic (In very much the same way as the SIP protocol works)

Soif you disconnect the router's adsl line you are still skype connected?
 
Unless u have a skype lan server that is not possible.Skype must connect to a server online to work.It will use internet traffic.
 
I'm sharing an ADSL connection with 2 friends wirelessly. Both of them are in different locations, but we are about 160 m from each other. Each one of us makes our own PPPOE connections.

I don't use Skype, rather GoogleTalk*. I need to be connected to the internet to call my friend, but once we're talking we can both disconnect our routers from the internet. The call still works until we end it. After that, we need to connect on PPPOE again to re-initialise a call.

When we talk to each other we have one hop via the 3rd dude's router that is effectively sitting "in the middle" of us. I haven't tested how quickly GTalk "reroutes" the call directly via our wireless connection, but it certainly does work. And copying files over GTalk we get about 2 Mbits/sec. The ADSL line is only 384 kbits/sec.

*Skype uses more bandwidth, about 2x as much as GTalk, more RAM and more CPU time. My computer is an old AMD 750 MHz with 256 MB of RAM. So GTalk works for me!
 
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