ATM0 drops + fallbacks

[iamkryoxx]

Howdy i'am new to cisco and i recently found out that my atm0 interface has lots of fallbacks..

ATM0 buffers, 1536 bytes (total 16, permanent 16):
     0 in free list (0 min, 16 max allowed)
     16 hits, 729960 fallbacks
     16 max cache size, 16 in cache
     0 hits in cache, 0 misses in cache

also the "show int atm0" shows up some drops..

sh int atm0
ATM0 is up, line protocol is up 
  Hardware is MPC ATMSAR (with Alcatel ADSL Module), address is 0026.cb25.7c5f (bia 0026.cb25.7c5f)
  MTU 4470 bytes, sub MTU 4470, BW 512 Kbit/sec, DLY 720 usec, 
     reliability 255/255, txload 2/255, rxload 27/255
  Encapsulation ATM, loopback not set
  Keepalive not supported 
  Encapsulation(s): AAL5
  10 maximum active VCs, 64 VCs per VP, 1 current VCCs
  VC Auto Creation Disabled.
  VC idle disconnect time: 300 seconds
  Last input never, output 00:00:01, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 393
  Queueing strategy: Per VC Queueing
  5 minute input rate 56000 bits/sec, 1 packets/sec
  5 minute output rate 5000 bits/sec, 3 packets/sec
     731696 packets input, 1046130477 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     351480 packets output, 26814253 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 unknown protocol drops
     0 output buffer failures, 0 output buffers swapped out

any luck to fix this?

Thanks in advance!

[lgijssel]

The output drops are in fact not many when compared to the total amount of traffic sent.

Output drops can have many causes, from temporary overloading the available bandwidth to the operation of qos.

With the amount seen here, no special actions are necessary.

With the fallbacks, the story is more or less the same. It all depends on the amount of time over which the value has accumulated. Best course of action is to monitor the parameter regularly and determine the hourly or daily increase.

Most probable cause is the quality or overbooking of the ATM link. Are you experiencing slow performance?

If not, there seems little need for concern.

regards,

Leo