I agree with Marko on this one.
The Delay cannot be verified to be 40/30/30 since you cannot measure how
many packets from the Priority Q are actually being serviced in relation to
the WFQ scheduler that only spits out one packet at a time.
Also, what delay are you referencing for a 40/30/30 share. Queuing delay
only?
What about CPU, Serialization which change pending the packet size. Sure,
Serialization delay is almost non-existent with Ethernet designs but it is
still there. Thus, you cannot guarantee effective throughput.
Paul
-- Paul Negron CCIE# 14856 CCSI# 22752 Senior Technical Instructor > From: gp <gs4me2me_at_gmail.com> > Reply-To: gp <gs4me2me_at_gmail.com> > Date: Sun, 7 Aug 2011 20:16:40 +0200 > To: 'Carlos G Mendioroz' <tron_at_huapi.ba.ar>, 'Marko Milivojevic' > <markom_at_ipexpert.com> > Cc: <ccielab_at_groupstudy.com> > Subject: RE: shape on 3560 > > So queue which is shaped has guaranteed bandwidth in relation to shared > queues? > > Gp > > > -----Original Message----- > From: Carlos G Mendioroz [mailto:tron_at_huapi.ba.ar] > Sent: Sunday, August 07, 2011 8:05 PM > To: Marko Milivojevic > Cc: gp; <ccielab_at_groupstudy.com> > Subject: Re: shape on 3560 > > Marko, > you say that all queues have guaranteed BW but not delay. > I don't fully understand that. > > Are you saying that the delay for a packet of some class is not bounded? > If not, delay is also guaranteed. > > If you have 3 queues, one with 50Mb shape and the other two 1/3 the BW > on a 100 Mb link, anything below congestion (and below 50Mb) will be > just served, but if the 3 queues try to get 40Mb, what will be the > effective throughput of each ? > I would say 40/30/30. > > -Carlos > > Marko Milivojevic @ 07/08/2011 14:22 -0300 dixit: >> All queues are guaranteed bandwidth, but not the delay. SRR is round-robin >> alghoritm. Shaped queues are assigned bandwidth first and whatever remains is >> used by shared queues, but servicing the data in queues is always equal >> between all the queues. >> >> When you enable PQ, Q1 is serviced until empty and only then Q2-4 are >> processed according to the SRR configuration and remaining bandwidth in the >> time interval. >> >> -- >> Marko Milivojevic - CCIE #18427 >> Senior Technical Instructor - IPexpert >> >> Free CCIE Training: http://bit.ly/vLecture >> >> Mailto: markom_at_ipexpert.com >> Telephone: +1.810.326.1444 >> Community: http://www.ipexpert.com/communities >> >> :: Sent from my phone. Apologies for errors and brevity. :: >> >> >> On Aug 7, 2011, at 2:42, "gp" <gs4me2me_at_gmail.com> wrote: >> >>> I read somewhere that shaped queue is processed before shared. Unfortunately >>> cannot find it:) >>> >>> Is it possible to guaranteed some traffic bandwidth to be processed before >>> other with limit in task that it cannot be mapped in priority queue because >>> some other traffic more important is mapped to priority queue? >>> >>> For example: >>> Q1 - traffic X - priority >>> Q2 - traffic XY - less important than traffic X, more important than traffic >>> XYZ >>> Q3&Q4 - traffic XYZ >>> >>> >>> Regards, >>> Gp >>> >>> >>> >>> -----Original Message----- >>> From: Marko Milivojevic [mailto:markom_at_ipexpert.com] >>> Sent: Saturday, August 06, 2011 10:46 PM >>> To: gp >>> Cc: ccielab_at_groupstudy.com >>> Subject: Re: shape on 3560 >>> >>> Sharing and shaping has nothing to do with priority queueing. I.e. >>> shaped traffic is not processed before shared - it's only limited to >>> certain percentage of the traffic, while shared queues are simply >>> guaranteed a minimum. >>> >>> You can configure shaping as a percentage of negotiated speed, of >>> course. By default 100% of interface bandwidth (negotiated speed) is >>> available for all queues. If you want to limit Q2 to say, 33% you can >>> configure it as "srr-queue bandwidth shape 0 3 0 0". However, if you >>> want to limit it to say 5 Mb/s REGARDLESS of the negotiated speed, >>> this cannot be done on 3560, as this is a policing and policing is not >>> available in the outbound direction on 3560. >>> >>> -- >>> Marko Milivojevic - CCIE #18427 >>> Senior Technical Instructor - IPexpert >>> >>> FREE CCIE training: http://bit.ly/vLecture >>> >>> Mailto: markom_at_ipexpert.com >>> Telephone: +1.810.326.1444 >>> Web: http://www.ipexpert.com/ >>> >>> On Sat, Aug 6, 2011 at 13:19, gp <gs4me2me_at_gmail.com> wrote: >>>> Thank you Marko for explanation, it helps. >>>> >>>> What confusing me if I have a task to guaranteed some traffic for example >>>> 10Mbps on giga interface on switch, and I cannot use priority queue, so I >>>> want to send that traffic before packet in shared queue in way to put it in >>>> shaped queue which will be served before shared queues. >>>> >>>> The problem is that I donbt know what type of interface will be connected >>>> to my switch (1Gbps or 100M) and that is value from which will be >>>> calculated value for shaping on particular queue. >>>> >>>> For example: >>>> Negotiated speed = 1Gbps >>>> Srr-queue bandwidth shape 0 100 0 0 >>>> Queue 2 will be shaped to 100Mbps >>>> >>>> Negotiated speed = 100Mbps >>>> Srr-queue bandwidth shape 0 100 0 0 >>>> Queue 2 will be shaped to 10Mbps >>>> >>>> In other way as I understand there is no way to hard code shape value >>>> regarding to negotiated speed? >>>> >>>> Regards, >>>> Gp >>>> >>>> >>>> >>>> >>>> -----Original Message----- >>>> From: Marko Milivojevic [mailto:markom_at_ipexpert.com] >>>> Sent: Saturday, August 06, 2011 7:42 PM >>>> To: gp >>>> Cc: ccielab_at_groupstudy.com >>>> Subject: Re: shape on 3560 >>>> >>>> It will be using the bandwidth available to the SRR. >>>> >>>> Cat2#sh mls qos interface fa0/18 queueing >>>> FastEthernet0/18 >>>> Egress Priority Queue : disabled >>>> Shaped queue weights (absolute) : 25 0 0 0 >>>> Shared queue weights : 25 25 25 25 >>>> The port bandwidth limit : 100 (Operational Bandwidth:100.0) <<<<<<< >>>> The port is mapped to qset : 1 >>>> >>>> See the "port bandwidth limit" line - that's the BW available to the >>>> SRR. It is derived from the negotiated speed by default, but can be >>>> limited using "srr-queue bandwidth limit" command on the interface. >>>> >>>> Now, let's see if configured bandwidth influences this in any way: >>>> >>>> interface FastEthernet0/18 >>>> bandwidth 50000 >>>> ! >>>> >>>> Cat2(config-if)#do sh mls qos int fa0/18 qu >>>> FastEthernet0/18 >>>> Egress Priority Queue : disabled >>>> Shaped queue weights (absolute) : 25 0 0 0 >>>> Shared queue weights : 25 25 25 25 >>>> The port bandwidth limit : 100 (Operational Bandwidth:100.0) >>>> The port is mapped to qset : 1 >>>> >>>> Doesn't look like it does. If I change the bandwidth limit. >>>> >>>> interface FastEthernet0/18 >>>> bandwidth 50000 >>>> srr-queue bandwidth limit 25 >>>> ! >>>> >>>> Cat2(config-if)#do sh mls qos int fa0/18 qu >>>> FastEthernet0/18 >>>> Egress Priority Queue : disabled >>>> Shaped queue weights (absolute) : 25 0 0 0 >>>> Shared queue weights : 25 25 25 25 >>>> The port bandwidth limit : 25 (Operational Bandwidth:27.28) >>>> The port is mapped to qset : 1 >>>> >>>> Whenever in doubt - ask IOS :-) >>>> >>>> -- >>>> Marko Milivojevic - CCIE #18427 >>>> Senior Technical Instructor - IPexpert >>>> >>>> FREE CCIE training: http://bit.ly/vLecture >>>> >>>> Mailto: markom_at_ipexpert.com >>>> Telephone: +1.810.326.1444 >>>> Web: http://www.ipexpert.com/ >>>> >>>> On Sat, Aug 6, 2011 at 01:18, gp <gs4me2me_at_gmail.com> wrote: >>>>> Hello experts, >>>>> >>>>> >>>>> >>>>> When doing shaping on 3560 interface does reference bandwidth is >>>>> configured >>>>> bandwidth with bandwidth command or negotiated speed? >>>>> >>>>> >>>>> >>>>> For example the switch port is connected on Fast Ethernet router interface >>>>> and I configured bandwidth 1000000 on switch port. >>>>> >>>>> With srr-queue bandwidth shape 0 100 0 0, will queue 2 be shaped on 10 or >>>>> 1 >>>>> Mbps? >>>>> >>>>> >>>>> >>>>> Thank you! >>>>> >>>>> >>>>> Blogs and organic groups at http://www.ccie.net >>>>> >>>>> _______________________________________________________________________ >>>>> Subscription information may be found at: >>>>> http://www.groupstudy.com/list/CCIELab.html >> >> >> Blogs and organic groups at http://www.ccie.net >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html >> >> >> >> >> >> >> > > -- > Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html Blogs and organic groups at http://www.ccie.netReceived on Sun Aug 07 2011 - 13:04:23 ART
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