Threshold values are not referring to bandwidth - the refer to queue depth (or buffers). The 3750 has buffers reserved per port and a pool of shared buffers, hence why the value can be greater than 100%. If the question asks to address output traffic based on bandwidth, you need to focus on shape and share commands. If it wants you to address traffic based on queue depth, you need to focus on thresholds.
DQ d...@cisco.com<mailto:d...@cisco.com> On Sep 3, 2012, at 11:36 AM, "Jason Murray" <murr...@usa.com<mailto:murr...@usa.com>> wrote: Ok so threshold is used a little differently. So yes default auto qos config queue 1 the priority queue has a threshold of 100 percent or more. I myself do really get the whole more than 100% but don't know if it matters so let me give an example of how to use threshold. So lets say for example you are to assign COS 2, 6 and 7 to que 4. And it also states if the link becomes 45 percent saturated then start dropping cos 6. You need to use thresholds to accomplish this So first you need to assign those cos values to queue four also keeping in mind that second requirement of dropping cos 6 once the link is 45 percent saturated. mls qos srr-queue output dscp-map queue 4 threshold 3 2 7 mls qos srr-queue output dscp-map queue 4 threshold 2 6 Now you notice how I split the COS values out between thresholds but they are still assigned to queue 4. The next command will address that mls qos queue-set output 2 threshold 2 100 100 100 45 Ok lets explain this last one so "output 2" corresponds to the queue set that is assigned to that particular port so in this case "queue set 2" Threshold 2 matches up with the the second command so that only affects COS 6 in queue 4 and not anything cos values assigned to queue 4. Now we assign those configurations to the interface by using the queue-set command int f1/0/1 queue-set 2 So that's what thresholds have to do with it. Jason ----- Original Message ----- From: Krishna Sent: 09/02/12 12:00 AM To: murr...@usa.com<mailto:murr...@usa.com>, Randall Crumm, Dan Quinlan \(daquinla\) Subject: Re: [OSL | CCIE_Voice] LAN Qos Question jason, reg: If you leave priority que out configured along with shape of 25 percent then essentially que 1 can have 100 percent of the bandwidth if needs it. Isn't it queue 1 takes whatever the value defined in the threshold i.e. for example mls qos queue-set output 1 threshold 1 138 138 92 138, this takes queue 1 to 138%, and once it is over it comes back to share mode, since the priority queue overwritten the shape, and left over is share value whatever defined at the interface level... please correct me if i m wrong.. thank you krishna. ________________________________ From: "murr...@usa.com<mailto:murr...@usa.com>" <murr...@usa.com<mailto:murr...@usa.com>> To: murr...@usa.com<mailto:murr...@usa.com>; Randall Crumm <rrcr...@yahoo.com<mailto:rrcr...@yahoo.com>>; Dan Quinlan (daquinla) <daqui...@cisco.com<mailto:daqui...@cisco.com>> Cc: ccie_voice@onlinestudylist.com<mailto:ccie_voice@onlinestudylist.com> Sent: Saturday, September 1, 2012 8:20 PM Subject: Re: [OSL | CCIE_Voice] LAN Qos Question > Priority goes in this order > > Priority queue out > Shape > Share > > If lets say for example you want cos 5 to be in the priority queue but it > also states that cos 5 should have no more than 25 percent of the bandwidth. > Of course in the mappings you need to put cos 5 in que 1. Then you need to > disable priority que out and use shape to give cos 5 only 25 percent (shape 4 > 0 0 0). If you leave priority que out configured along with shape of 25 > percent then essentially que 1 can have 100 percent of the bandwidth if needs > it. Make sure you read the question carefully to see what it is wanting. > > Jason > > > > > > On 9/1/12 at 10:56 AM, Randall Crumm wrote: > > > Hi, > > I have a question about LAN QoS. > > > > If I do shape and share on an interface do I have to disable priority queue > > out on the interface? > > > > > > > > Cheers, > > Randall _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com<http://www.ipexpert.com/> Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com<http://www.platinumplacement.com/>
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
