Increase buffer size Cisco

Hi,

I'm getting a lot of packet drop on an interface and i suspect its because the traffic is burst type and the buffer is to small to handle it.

I want to increase the buffer size, but a little unsure what the cmds are to do it ?

thanks,
-P-HendersonAsked:
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greg wardConnect With a Mentor Systems EngineerCommented:
have you tried a show buffers to see if you need to change this?

buffers fastethernet 0/0 permanent 65536

the above might be overkill...

Greg
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-P-HendersonAuthor Commented:
Buffer elements:
     1505 in free list (500 max allowed)
     26478789 hits, 0 misses, 1024 created

Public buffer pools:
Small buffers, 104 bytes (total 50, permanent 50, peak 89 @ 7w0d):
     49 in free list (20 min, 150 max allowed)
     7342901 hits, 13 misses, 39 trims, 39 created
     0 failures (0 no memory)
Middle buffers, 600 bytes (total 25, permanent 25, peak 46 @ 7w0d):
     23 in free list (10 min, 150 max allowed)
     2099422 hits, 11 misses, 33 trims, 33 created
     0 failures (0 no memory)
Big buffers, 1536 bytes (total 50, permanent 50, peak 59 @ 7w0d):
     42 in free list (5 min, 150 max allowed)
     22491327 hits, 3 misses, 9 trims, 9 created
     0 failures (0 no memory)
VeryBig buffers, 4520 bytes (total 17, permanent 10, peak 19 @ 7w0d):
     1 in free list (0 min, 100 max allowed)
     122792 hits, 8 misses, 924 trims, 931 created
     0 failures (0 no memory)
Large buffers, 5024 bytes (total 1, permanent 0, peak 2 @ 7w0d):
     1 in free list (0 min, 10 max allowed)
     25211 hits, 1 misses, 917 trims, 918 created
     0 failures (0 no memory)
Huge buffers, 18024 bytes (total 1, permanent 0, peak 4 @ 7w0d):
     1 in free list (0 min, 4 max allowed)
     165492 hits, 5 misses, 925 trims, 926 created
     0 failures (0 no memory)

Interface buffer pools:
Syslog ED Pool buffers, 600 bytes (total 132, permanent 132):
     100 in free list (132 min, 132 max allowed)
     269 hits, 0 misses
RxQFB buffers, 2040 bytes (total 904, permanent 904):
     902 in free list (0 min, 904 max allowed)
     142426 hits, 0 misses
RxQ0 buffers, 2040 bytes (total 1200, permanent 1200):
     700 in free list (0 min, 1200 max allowed)
     500 hits, 0 misses
RxQ1 buffers, 2040 bytes (total 128, permanent 128):
     1 in free list (0 min, 128 max allowed)
     128 hits, 1 fallbacks
RxQ2 buffers, 2040 bytes (total 128, permanent 128):
     0 in free list (0 min, 128 max allowed)
     128 hits, 0 fallbacks, 0 trims, 0 created
     0 failures (0 no memory)
RxQ3 buffers, 2040 bytes (total 128, permanent 128):
     1 in free list (0 min, 128 max allowed)
     14643311 hits, 142425 fallbacks
RxQ4 buffers, 2040 bytes (total 128, permanent 128):
     0 in free list (0 min, 128 max allowed)
     1097672 hits, 1195532 misses
RxQ5 buffers, 2040 bytes (total 128, permanent 128):
     64 in free list (0 min, 128 max allowed)
     64 hits, 0 misses
RxQ6 buffers, 2040 bytes (total 128, permanent 128):
     0 in free list (0 min, 128 max allowed)
     142 hits, 14 misses
RxQ7 buffers, 2040 bytes (total 192, permanent 192):
     63 in free list (0 min, 192 max allowed)
     5884700 hits, 0 misses
RxQ8 buffers, 2040 bytes (total 64, permanent 64):
     0 in free list (0 min, 64 max allowed)
     14860263 hits, 14853095 misses
RxQ9 buffers, 2040 bytes (total 1, permanent 1):
     0 in free list (0 min, 1 max allowed)
     1 hits, 0 misses
RxQ10 buffers, 2040 bytes (total 64, permanent 64):
     0 in free list (0 min, 64 max allowed)
     64 hits, 0 fallbacks
RxQ11 buffers, 2040 bytes (total 16, permanent 16):
     0 in free list (0 min, 16 max allowed)
     16 hits, 0 misses
RxQ12 buffers, 2040 bytes (total 96, permanent 96):
     0 in free list (0 min, 96 max allowed)
     96 hits, 0 misses
RxQ13 buffers, 2040 bytes (total 16, permanent 16):
     0 in free list (0 min, 16 max allowed)
     16 hits, 0 misses
RxQ15 buffers, 2040 bytes (total 4, permanent 4):
     1 in free list (0 min, 4 max allowed)
     206091111 hits, 206091108 misses
IPC buffers, 2048 bytes (total 300, permanent 300):
     296 in free list (150 min, 500 max allowed)
     1382494 hits, 0 fallbacks, 0 trims, 0 created
     0 failures (0 no memory)

Header pools:
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-P-HendersonAuthor Commented:
looking at the buffers i think your right, the buffer pools look ok.

Its a high number of output drops i'm getting on an interface.



Router 2#sh int gi0/16
GigabitEthernet0/16 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is ec30.9181.8c90 (bia ec30.9181.8c90)
  Description: *****
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 25/255, rxload 3/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseLX SFP
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output 00:00:19, output hang never
  Last clearing of "show interface" counters 2d20h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 37594064
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  30 second input rate 14157000 bits/sec, 7000 packets/sec
  30 second output rate 99377000 bits/sec, 11801 packets/sec
     1963134151 packets input, 469942764558 bytes, 0 no buffer
     Received 829 broadcasts (0 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     3416471468 packets output, 3790907026574 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     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
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-P-HendersonAuthor Commented:
I think i'll disable CEF
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greg wardSystems EngineerCommented:
Did that fix it?
Can you stress test the interface to measure throughput?

Greg
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-P-HendersonAuthor Commented:
Unable to disable CEF, its a ME3400 switch, it wont let me disable CEF on that platform.

Its a production interface so i'm limited to what tests i can perform.

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greg wardConnect With a Mentor Systems EngineerCommented:
Try reading this http://www.frameip.com/dos-cisco/queue_drops.pdf
has useful hidden commands
show interfaces stats
show interfaces ethernet 0/0 switching

Greg
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-P-HendersonAuthor Commented:
Thanks Greg
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