Interesting People mailing list archives
Re: Skype asks FCC to open up cellular networks
From: David Farber <dave () farber net>
Date: Tue, 27 Feb 2007 07:05:14 +0900
This has gotten to be one of the most "nasty" discussions on IP n a while. (not just the "nasty" noted below but emails I have not posted. Reminds me of the net neutrality discussions. Too much emotion.
Dave Begin forwarded message: From: Brad Templeton <btm () templetons com> Date: February 26, 2007 6:19:34 PM JST To: David Farber <dave () farber net> Cc: dpreed () reed com, brett () lariat net Subject: Re: [IP] Re: Skype asks FCC to open up cellular networks
Skype does nothing magic here. If you "call somebody" on your Skype connection, the bits sent are (strangely and wonderfully) exactly those bits needed to send your voice to his machine.technical -- is that Skype works by "robbing" bandwidth from its users and their ISPs. Skype does not buy enough bandwidth to route or connect all of the calls placed via its network.
The real answer is somewhere between Brett's point and David's surprisingly nasty rebuttal. VoIP is generally a peer 2 peer application, using the net exactly as it was intended. A VoIP phone company does not need to buy more than a trivial amount of switching bandwidth in order to operate in the ideal end to end internet, so the line about Skype "not buying enough bandwidth" is perhaps the source of confusion. The problem occurs when users are behind NAT, which happens by their own choice, or the choice of their facility, or because their ISP does not provide them with enough routable IP addresses (or for example, IPv6 which some P2P apps can use though I am unsure if Skype does.) In this situation sometimes the P2P applications are forced to not route the traffic end-to-end as they would like to. Many companies took the path of installing relay servers and buying bandwidth to relay the traffic when the two endpoints can't reach one another directly. Skype took the more unusual approach of using other computers running Skype on reachable machines as the relays. While this is fairly well known, and I think spelled out in the Skype EULA, it is true that many Skype users are not aware their machine is doing this, and that the bandwidth they have paid for is going to this purpose. Because Skype reveals this on their web site, it's not really stealing, but because many people are unaware, it often feels that way. Skype claims they limit bandwidth used by relays to 1kb/second per channel, and about 5kb/second total, which suggests that they must use multiple relays simultaneously, as a single GIPS voice channel needs at least 2kb/second, I believe. It's clear that they could be more explicit about this, however. For most ISPs, having the relay be on the same ISP is a big win for the user and causes minimal trouble for the ISP. Brett runs an unusual ISP which is based on wireless. For him, it is not a win. I must admit that sometimes Brett seems to act as though all network applications should be designed with the constraints of a wireless ISP in mind. While I don't think it is bad to think about those constraints, it is wrong to declare applications as evil because they are designed with the constraints of wired ISPs. Wireless ISPs do not have full duplex transmission, they can't do upstream and downstream at the same instant, and traffic between peers is often particularly expensive because it goes to an access point and back, and in the case of a relaying peer goes through once again. These constraints lead Brett to wish to run his ISP differently, and this is as it should be. I believe he is fairly open with his customers that he can't sell them the sort of service that would be no problem on a wired network. ------------------------------------------- Archives: http://v2.listbox.com/member/archive/247/@now Powered by Listbox: http://www.listbox.com
Current thread:
- Skype asks FCC to open up cellular networks David Farber (Feb 22)
- <Possible follow-ups>
- Skype asks FCC to open up cellular networks David Farber (Feb 24)
- Re: Skype asks FCC to open up cellular networks David Farber (Feb 25)
- Re: Skype asks FCC to open up cellular networks David Farber (Feb 25)
- Re: Skype asks FCC to open up cellular networks David Farber (Feb 25)
- Re: Skype asks FCC to open up cellular networks David Farber (Feb 25)
- Re: Skype asks FCC to open up cellular networks David Farber (Feb 26)
- Re: Skype asks FCC to open up cellular networks David Farber (Feb 26)
- Re: Skype asks FCC to open up cellular networks David Farber (Feb 26)
- Re: Skype asks FCC to open up cellular networks David Farber (Feb 28)