My understanding of peer-to-peer was that it indicated that all hosts had equal ability to originate or terminate (as in accept, not as in end) sessions. That is, the role of client or server is defined by the choice of the application and/or software on the host and not by the network.
IP is a peer to peer network because all nodes are equal at the protocol level. IP does not make a protocol-level distinction between clients or servers. See: http://en.wikipedia.org/wiki/Peer-to-peer Noting specifically from http://en.wikipedia.org/wiki/Client-server#Comparison_to_peer-to-peer_architecture It would appear to me that IP is, by definition peer to peer while TCP seems inherently client-server in most implementations and UDP is ambiguous and can be used in either mode, as in DNS where a recursive resolver operates simultaneously as both a server and a client or peer and an authoritative server with secondaries also operates simultaneously as a server and as a peer. You are correct about the peer to peer or not nature of an architecture being possibly different at different layers, but, I don't think you are right in saying that having routers in between makes two IP nodes not peers. Owen On Feb 19, 2011, at 11:42 AM, Dave CROCKER wrote: > > > On 2/19/2011 10:11 AM, kmedc...@dessus.com wrote: >> >> And that has nothing to do with whether a protocol is a peer protocol or not. >> IP is a peer-to-peer protocol. As SMTP is implemented over IP, it is also a >> peer-to-peer protocol. > > > At each layer of an architecture, the question of whether a mechanism is peer > to > peer can be newly defined. Even within a layer it can be, depending upon > configuration choices. > > IP is typically /not/ peer to peer, since getting from the originating host to > the target host is typically mediated by many routers. That is the essence of > /not/ being peer to peer. > > One layer up, we find that TCP typically /is/ peer-to-peer. > > "SMTP" as a one-hop email transmission protocol is peer-to-peer from the SMTP > client to the corresponding SMTP server. However email exchange from an > author's MUA to a recipient's MUA is, again, the essence of /not/ being peer > to > peer. It is typically massively mediated by lots of different email servers. > > One could configure two MUAs to talk with each other 'directly' using SMTP, > but that's never done. > > Instant message services similarly are not peer-to-peer technical terms. > > d/ > > -- > > Dave Crocker > Brandenburg InternetWorking > bbiw.net
