Thanks James - If the queue-limit percent 100 alleviates the issue for the one service instance Ive applied it to, I might look at implementing your solution, if you have had success with it eliminating tail drops.
Side note - Are "most" using this type of solution on the ME3600's...we've only got approx 100 services deployed on 8 ME's, and havent run into any issues until now with tail drops....but this service is provided by a carrier that requires insane shaping to be applied at both ends(PE/CE), or there service simply works horribly. We have recently purchased a whole bunch of ASR920's(Instead of ME3600's) - Are they also afflicted with this issue? Thanks again to all who replied....much appreciated. ________________________________________ From: James Bensley <[email protected]> Sent: Wednesday, 16 September 2015 10:49 PM To: [email protected]; CiscoNSP List Subject: Re: [c-nsp] Tail drops on ME3600 with shaping policy On 16 September 2015 at 10:10, CiscoNSP List <[email protected]> wrote: > > Thanks very much James - Very helpful! > > > So there's no singular way I can test this (queue-limit percent 100) on a > single service instance under an Interface? i.e. Id have to re-do the entire > qos policy for the Interface and associated service instances? > > > In our current situation, we have ~30 service instances, all varying > subscribed speeds under one Interface...only a few of them are showing tail > drops, so I was hoping to test the queue limit "fix" on one or two of > them...but from what Im reading in your reply, this doesnt look to be > possible? As per Adam's suggestion you can apply the policy lower down in the tree of physical port > VLAN/service instance > individual traffic class. Also you could match based on service instance in a parent policy applied at the interface level. There's often more than way to to achieve the same result. Spyros mentioned about over-buffering. I don't see any problem with this, with "queue-limit percent 100" the IOS resource manager will allocate more buffers to the port as requried (as throughput increases) and de-allocated them when they aren't need, otherwise you couldn't have more than one traffic class on the entire switch with "queue-limit percent 100" configured. The idea/approach I use is that the command can be applied everywhere and just let the ASIC handle it. This has removed tail-drops for us without any further issues or repercussions. Cheers, James. _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
