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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical RE: fractional gigabit ethernet links?
I may be missing something but.. presumably their rate-limiting involves some form of queuing/buffering.. in which case assuming the ping is the only thing occuring, when the rate hits the limit it will queue, delay and slow down the echo/reply and no packets should be lost? on the other hand, if as is i think suggested below theres no buffer ie when it hits the limit it starts dropping then i dont think thats a good way of rate limiting as it only works for tcp and the network really needs to provide a way to slow the ip layer down. i cant see how that will provide a usable service... Steve -- Stephen J. Wilcox IP Services Manager, Opal Telecom http://www.opaltelecom.co.uk/ Tel: 0161 222 2000 Fax: 0161 222 2008 On Mon, 15 Jul 2002, Phil Rosenthal wrote: > > Hello Alex, > > I'd say this sounds obvious, but may be deceptively so... > If you are taking a pipe capable of 1000 mbit, and rate-limiting it to > 311 mbit, the logic used may be: > > In the last 1000 msec have there been more than 311mbits? If yes: drop. > > What you want is to shape the traffic, so the rule would be: > In the last 1000 msec have there been more than 311 mbits? If yes: store > until the msec period is up, then transmit. > > If you are pushing 100 mbits over this link, it is entirely likely that > there will be a few sub-second burts up to 1000 mbit, and a few > sub-second drops to 0mbit. > > An option for you would be to just figure out what the exact > rate-limiting rules are, and then shape it into those rules on your side > of the link -- assuming they wont change it to a shaping rule. > > --Phil > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of > Alex Rubenstein > Sent: Monday, July 15, 2002 10:48 PM > To: [email protected] > Subject: fractional gigabit ethernet links? > > > > > Hello, > > I'm trying to troubleshoot a problem with a fractional (311 mbit/second) > gigabit-ethernet line provided to me by a metro access provider. > Specifically, it is riding a gig-e port of a 15454. > > The behavior we are seeing is an occasional loss of packets, adding up > to a few percent. When doing a cisco-type ping across the link, we were > seeing a consistent 3 to 4 percent loss. > > For fun, the provider brought it up to 622 mbit/second, and loss dropped > considerably, but still hangs at about 1 to 2 percent. > > There is no question in my mind the issue is with the line, as we've > done a wide variety of tests to rule out the local equipment (MSFC2s, > FYI). > > Any clues would be exceptional. > > > > -- Alex Rubenstein, AR97, K2AHR, [email protected], latency, Al Reuben -- > -- Net Access Corporation, 800-NET-ME-36, http://www.nac.net -- > > > >
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