Re: Puzzling QoS Issue

yeh without further tests it's hard to say what the issue is, what's the
uptime? is the code/license identical to your other working router ;)

--
BR
Tony
Sent from my iPhone on 3
On 20 Apr 2013, at 00:50, Joe Astorino <joeastorino1982_at_gmail.com> wrote:
> CPU and memory seem to be OK.  sh proc cpu shows it sitting about 7-10% when
the problem occurs.  sh proc cpu history does not show any really bad spikes.
sho proc mem seems to show I have plenty of free RAM as well.
>
>
> On Fri, Apr 19, 2013 at 7:43 PM, Joe Astorino <joeastorino1982_at_gmail.com>
wrote:
> Sorry, 2GB of RAM is what it has
>
>
> On Fri, Apr 19, 2013 at 7:41 PM, Matt Bentley <mattdbentley_at_gmail.com>
wrote:
> Interesting.  I've done testing with Spirent and other traffic-gen
platforms.  I never saw shaping add to the latency - until I actually got up
close to the CIR - maybe slightly with a lower-end platform.  But I don't
think shaping even activates until it senses backpressure and activates
"itself".
>
>
> On Fri, Apr 19, 2013 at 4:17 PM, Tony Singh <mothafungla_at_gmail.com> wrote:
> The reason why you get the extra delay when the policy is applied is down to
the extra work the CPU has to do on top of inbound congestion, what's your
memory/free?
>
> I would also raise a TAC to get the definitive answer "show tech-support" &
pass to them
>
> --
> BR
>
> Sent from my iPhone on 3
>
> On 19 Apr 2013, at 23:13, Joe Astorino <joeastorino1982_at_gmail.com> wrote:
>
> > Another interesting fact - When the policy is applied as shown above, the
> > problem only occurs when the inbound RX is congested.
> >
> > So basically, if the service-policy is applied outbound towards the WAN
as
> > shown, and the output utilization of the WAN link (TX) is low, and the
> > inbound (RX) utilization is low,  everything is fine.
> >
> > In the event that the inbound utilization of the interface (RX) is
> > significant, and the policy is applied outbound as usual, the policy is
> > adding the 200-400ms extra delay. If I remove the policy, the extra delay
> > goes away.
> >
> > I guess I don't understand why inbound congestion would change how the
> > outbound queue / shaping works.
> >
> > input is low, output is low, policy applied: fine
> > input is high, output is low, policy not applied: expected poor response
> > times
> > input is high, output is low, policy is applied: expected poor response
> > time PLUS an additional 200-400ms of delay
> >
> >
> > On Fri, Apr 19, 2013 at 5:49 PM, Joe Astorino
<joeastorino1982_at_gmail.com>wrote:
> >
> >> I have a 3945 ISR router connected via a GigabitEthernet link to a
service
> >> provider that is providing 10Mbps WAN access.  I wish to use CBWFQ and
the
> >> service provider requires dot1q tagging.  As such, I must shape my
> >> sub-interface and use a hierarchical type QoS policy...no big deal
> >>
> >> policy-map WAN-EDGE
> >> class VOICE
> >>  priority percent 20
> >> !
> >> class VIDEO
> >>  bandwidth remaining percent 60
> >>  queue-limit 128 packets
> >> !
> >> class APPS_SIGNALING
> >>  set dscp af21
> >>  bandwidth remaining percent 30
> >> !
> >>  class class-default
> >>  bandwidth remaining percent 10
> >> !
> >> !
> >> policy-map SHAPE-OUT
> >> class class-default
> >>  shape average 10000000
> >>   service-policy WAN-EDGE
> >> !
> >> !
> >> int gi0/1.2
> >> encapsulation dot1q 2
> >> ip address ...
> >> service-policy output SHAPE-OUT
> >>
> >>
> >> Here is the very strange thing.  Even when the TX of this WAN interface
is
> >> barely being used, when and only when the service-policy is applied, the
> >> response in pings to anything behind this router increase immediately by
> >> 200-400ms.  Immediately after removing the service-policy things return
to
> >> normal.
> >>
> >> Investigating the output of "show policy-map interface" reveals a large
> >> number of output drops in the shaper class-default. So far I have tried
> >>
> >> - increasing the queue-limit to many different combinations
> >> - increasing the burst size
> >>
> >> I also have the exact same configuration on another remote site router
> >> running the same version of IOS with the same setup (10Mbps Ethernet WAN
> >> link) on the same platform.
> >>
> >> I'm really baffled as to what would cause this.  Any insight
appreciated.
> >>
> >>
> >>
> >> --
> >> Regards,
> >>
> >> Joe Astorino
> >> CCIE #24347
> >> http://astorinonetworks.com
> >>
> >> "He not busy being born is busy dying" - Dylan
> >>
> >
> >
> >
> > --
> > Regards,
> >
> > Joe Astorino
> > CCIE #24347
> > http://astorinonetworks.com
> >
> > "He not busy being born is busy dying" - Dylan
> >
> >
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> --
> Regards,
>
> Joe Astorino
> CCIE #24347
> http://astorinonetworks.com
>
> "He not busy being born is busy dying" - Dylan
>
>
>
> --
> Regards,
>
> Joe Astorino
> CCIE #24347
> http://astorinonetworks.com
>
> "He not busy being born is busy dying" - Dylan
Blogs and organic groups at http://www.ccie.net