CoS, ToS, QoS work on the information units queued in a buffer of a device. I think that, in the same way of a circuit switched network, an establishment phase could exist. In this phase the network could reserve the right resources. i.e. virtual circuit, bandwidth, .... Thanks. ----- Original Message ----- From: "Mike S" <ietf@xxxxxxxxxxxxxxx> To: "Daniele Giordano" <d.giordano@xxxxxxxxxx> Cc: <ietf@xxxxxxxx> Sent: Monday, March 28, 2005 1:40 PM Subject: Re: reduce jitter in routed network for voip applications > At 06:09 AM 3/28/2005, Daniele Giordano wrote... > >RTP is transparent at the transport layer. We analyse TCP and UDP: > >TCP is connection oriented and so the communication begins with the > >definition of a virtual circuit. > >A virtual circuit is a temporary connection of sequence nodes with relative > >reservation of bandwidth. > >A connection oriented service gives the certainty that all information units > >use the same nodes with a same medium latency. > >Same latency maintains reduced the jitter. > > That is incorrect unless _other_, stateful protocols (ex. RSVP, integrated services) are in use throughout the entire network. That is not the general case. > > IP routes on a per hop basis, whether TCP or UDP. There is no "virtual circuit" created, except at the endpoints. > > >I think that RTP should use a layer 4 connection oriented protocol (like > >TCP) but without retransmissions of information units with excessive delay > >or errors (like UDP). > > > >What do you think about this? > > You're trying to solve a problem which is incorrectly defined, and therefore doesn't exist. > > Diffserv already provides a QoS mechanism for VoIP and does not require gateways to maintain state for each connection. It, like Intserv, cannot be assumed to exist through any random Internet path. RFC2474, RFC2475. > > > > _______________________________________________ > Ietf mailing list > Ietf@xxxxxxxx > https://www1.ietf.org/mailman/listinfo/ietf > _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf