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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?
Since this is being done with the 15454s this is not true rate limiting, more its a matter of STS channels being made available for use on the Vlan assigned to the two GigE ports. We have experienced this problem when sending traffic in excess of 250mbps through either: a) 4 or more 15454 hops that tired to achieve timing off of eachother rather than a stratum one source: <timing>===<15454>===<15454>===<15454>===<15454>===<15454> OR b) a 15454 that "uplinked" its OC48 backhaul through an active DWDM device (in our case a Sycamore SN8000) when both the SN8000 and 15454 were again not on the same stratum one source : <15454>===<sn8000>===<sn8000>===<15454> By not allowing a timing source to be more than 4 hops from any chassis and by ensuring that all DWDM devices in between are also timed the same, we have pushed up to 605mbps over a 15454 GigE link with no recorded packet loss. Hope this helps Alex, Vin PS As another aside we have seen problems when simultaneously using both ports on the 2 x GigE card for more then 200mbps a piece, but not with any regularity. -vb ----- Original Message ----- From: "Sush Bhattarai" <[email protected]> To: "Alex Rubenstein" <[email protected]> Cc: <[email protected]> Sent: Monday, July 15, 2002 11:57 PM Subject: Re: fractional gigabit ethernet links? > > Might want to query your provider as to where the rate limitting is being > done. In some cases, if rate limit is being done egress from the layer 3 > infracture towards the MAN layer 2 equipment, there might be a lack of > processing power on that device, causing the drops. Of course this will > depend on the type of device and whether the rate limiting is being done on > hardware or not too. > > Sush > > > > > > > > > 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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