[c-nsp] ME3600X Output Drops

[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