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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Last Mile QoS WAS: RE: QOS or more bandwidthy
On Tue, 29 May 2001, Nathan Stratton wrote: > > On Tue, 29 May 2001, Pete Kruckenberg wrote: > > > A 1536-byte frame has a fairly significant impact (~8ms) at > > 1.5Mb/s. QoS appears to have diminishing return as you move > > beyond 45Mbps, at least as far as multi-service networks go. > > Maybe QoS isn't necessary or useful in the core if you have > > line-speed switching and no congestion on an OC-X/DWDM > > network. > > It has even a larger impact on a 128K frac T1 (~93ms). QoS is a big help, > but at slower speeds you also need to deal with fragmentation and the > layer 2 transport. I am surprised that there has been so little movement > as far as QoS and efficiency in regards to VoIP. Take a standard voice call > using G.726 at 32 kbps, you get 40 bytes of voice every 10 ms. Now add on > your 20 byte IP header, 8 bytes UDP, and 12 byte RTP header. So now we are > at 80 bytes and most of the time we are shoving this on ATM so our 32K > voice stream now sucks 84.8 kbps. > > If you are interested in more info on QoS and Voice/Data over last mine > networks check out my website: > > http://www.robotics.net/papers/integratedvoice.html > > > ><> > Nathan Stratton CTO, Exario Networks, Inc. > [email protected] [email protected] > http://www.robotics.net http://www.exario.net > >
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