Hi Michael, Let me put how I understand it, if it's wrong I'd like someone to correct me please.
Imagine whole buffer for egress queue of one interface, this whole buffer is divided by four queues. But maybe at some point some queues might need more buffers than others, so they don't reserve specific amount of buffers for every queue. Instead it's better to reserve a percent. that is what reserved means, it's not the 3rd threshold. example: Q1 -> reserved 50% Q2 -> reserved 30% Q3 -> reserved 80% Q4 -> reserved 10% After all reservations, all the rest of buffers stays in common pool of buffers, which may be allocated to other queues per demand. for example consider the following: mls qos queue-set output 1 threshold 1 120 140 50 140 In this example thresholds are: T1 - 120 T2 - 140 T3 - full queue T1 means, when 50 per cent of reserved is already used, it will try to borrow from common pool up to 120 per cent. Same for T2, only up to 140 per cent. And T3 -> will drop, only when there is no more buffers available, neither in reserved nor in common pool. If this is not right, please someone correct! Regards, On Sun, Jun 5, 2011 at 6:55 PM, Michael Luo <hout...@gmail.com> wrote: > Also per > http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/configuration/guide/swqos.html#wp1163863 > , > > "The drop-threshold percentage for threshold 3 is predefined. *It is set > to the queue-full state. *" > > If it is set to the queue-full state, shouldn't it be 100 instead of 50? > > Thanks! > Michael > > > On Sun, Jun 5, 2011 at 12:51 PM, Michael Luo <hout...@gmail.com> wrote: > >> Can somebody help me understand the statement on >> http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/configuration/guide/swqos.html#wp1284809 >> : >> >> "Each queue has three threshold values. The QOS label is determines which >> of the three threshold values is subjected to the frame. Of the three >> thresholds, *two are configurable (explicit) and one is not (implicit)*." >> >> I'm curious about the "implicit" threshold that was NOT configurable. >> >> When I used the command "show mls qos queue-set", I got the following. >> >> Queueset: 1 >> Queue : 1 2 3 4 >> ---------------------------------------------- >> buffers : 25 25 25 25 >> threshold1: 100 200 100 100 >> threshold2: 100 200 100 100 >> * reserved : 50 50 50 50* >> maximum : 400 400 400 400 >> >> Was the line "reserved" corresponding to the "implicit" threshold? If >> yes, I think it's configurable with the following command: >> >> SW(config)#mls qos queue-set output 1 threshold 2 60 80 ? >> <1-100> enter *reserved threshold* 1-100 >> >> Did I misunderstand it? >> >> Thanks! >> Michael >> > > > _______________________________________________ > 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 >
_______________________________________________ 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
