[c-nsp] ME3600X Output Drops

[Ivan]

Thanks George.  I am raising a SR to get some more information too. Are 
you able to explain how the queue-limit of 2457 was selected? Also were 
you given a version for the increase in the default queue size?  I am 
running me360x-universalk9-mz.152-2.S1.bin

Cheers

Ivan


On 23/Aug/2012 5:48 p.m., George Giannousopoulos wrote:
> Hi Ivan,
>
> In fact the default queue limit in 3800x/3600x is quite small
> We also had issues with drops in all interfaces, even without congestion
>
> After some research and an SR with Cisco, we have started applying qos 
> on all interfaces
>
> policy-map INTERFACE-OUTPUT-POLICY
>   class dummy
>   class class-default
>    shape average X00000000
>    queue-limit 2457 packets
>
>
> The dummy class does nothing.
> It is just there because IOS wouldn't allow changing queue limit otherwise
>
> Also there were issues with the policy counters which should be resolved after15.1(2)EY2
> Cisco said they would increase the default queue sizes in the second half of 2012..
> So, I suggest you try the latest IOS version and check again
>
> 10G interfaces had no drops in our setup too.
>
> Regards
> George
>
>
> On Thu, Aug 23, 2012 at 1:34 AM, Ivan <cisco-nsp at itpro.co.nz 
> <mailto:cisco-nsp at itpro.co.nz>> wrote:
>
>     Replying to my own message....
>
>     * Adjusting the hold queue didn't help.
>
>     * Applying QOS and per referenced email stopped the drops
>     immediately - I
>     used something like the below:
>
>     policy-map leaf
>     class class-default
>     queue-limit 491520 bytes
>
>     policy-map logical
>     class class-default
>     service-policy leaf
>
>     policy-map root
>     class class-default
>     service-policy logical
>
>     * I would be interested to hear if others have ended up applying a
>     similar
>     policy to all interfaces.  Any gotchas?  I expect any 10Gbps
>     interfaces
>     would be okay without the QoS - haven't seen any issue on these
>     myself.
>
>     *Apart from this list I have found very little information around this
>     whole issue.  Any pointers to other documentation would be
>     appreciated.
>
>     Thanks
>
>     Ivan
>
>     Ivan
>
>     > Hi,
>     >
>     > I am seeing output drops on a ME3600X interface as shown below
>     >
>     > GigabitEthernet0/2 is up, line protocol is up (connected)
>     >   MTU 9216 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
>     >      reliability 255/255, txload 29/255, rxload 2/255
>     >   Encapsulation ARPA, loopback not set
>     >   Keepalive set (10 sec)
>     >   Full-duplex, 1000Mb/s, media type is RJ45
>     >   input flow-control is off, output flow-control is unsupported
>     >   ARP type: ARPA, ARP Timeout 04:00:00
>     >   Last input 6w1d, output never, output hang never
>     >   Last clearing of "show interface" counters 00:12:56
>     >   Input queue: 0/75/0/0 (size/max/drops/flushes); Total output
>     drops: 231
>     >   Queueing strategy: fifo
>     >   Output queue: 0/40 (size/max)
>     >   30 second input rate 10299000 bits/sec, 5463 packets/sec
>     >   30 second output rate 114235000 bits/sec, 12461 packets/sec
>     >      3812300 packets input, 705758638 bytes, 0 no buffer
>     >      Received 776 broadcasts (776 multicasts)
>     >      0 runts, 0 giants, 0 throttles
>     >      0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
>     >      0 watchdog, 776 multicast, 0 pause input
>     >      0 input packets with dribble condition detected
>     >      9103882 packets output, 10291542297 bytes, 0 underruns
>     >      0 output errors, 0 collisions, 0 interface resets
>     >      0 unknown protocol drops
>     >      0 babbles, 0 late collision, 0 deferred
>     >      0 lost carrier, 0 no carrier, 0 pause output
>     >      0 output buffer failures, 0 output buffers swapped out
>     >
>     > I have read about similar issues on the list:
>     > http://www.gossamer-threads.com/lists/cisco/nsp/157217
>     > https://puck.nether.net/pipermail/cisco-nsp/2012-July/085889.html
>     >
>     > 1. I have no QoS policies applied to the physical interface or EVCs.
>     > Would increasing the hold queue help?  Is there a recommended
>     value - the
>     > maximum configurable is 240000.  What is the impact on the 44MB
>     of packet
>     > buffer.
>     >
>     > 2. If the hold queue isn't an option is configuring QoS required to
>     > increase the queue-limit from the default 100us.  Again are
>     there any
>     > recommended values and what impact is there on the available 44MB of
>     > packet buffer.
>     >
>     > 3. I have found that when applying policies to the EVCs the
>     "show policy
>     > map" output does not have information for the queue-limit as I
>     have seen
>     > when applying polices to the physical interface.  Does this mean
>     that EVCs
>     > will still suffer from output drops?
>     >
>     > Thanks
>     >
>     > Ivan
>
>
>
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