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Webcast-Catalyst9k
New Member

Please help!! WAN router "misses in cache" keep increasing in "show buffer"

Hi all,

 

I see ""misses in cache" keep increasing for Gi0/1 when using "show buffer".

Yet,  no increasing of "no buffer" when using "show int gi0/0".

Also, no "cache misses" when using "show int gi0/1 switching"

-------------------------------------------------------

Router#show buffer

Private particle pools:
GigabitEthernet0/0 buffers, 1664 bytes (total 768, permanent 768):
     0 in free list (0 min, 768 max allowed)
     768 hits, 0 fallbacks
     768 max cache size, 512 in cache
     3600120405 hits in cache, 0 misses in cache
GigabitEthernet0/1 buffers, 1664 bytes (total 768, permanent 768):
     0 in free list (0 min, 768 max allowed)
     768 hits, 0 fallbacks
     768 max cache size, 512 in cache
     2726795893 hits in cache, 200441 misses in cache

---------------------------------------------------------------------

Router# sh int gi0/1 | be rate
  Queueing strategy: fifo
  Output queue: 0/768 (size/max)
  30 second input rate 4693000 bits/sec, 1611 packets/sec
  30 second output rate 2979000 bits/sec, 1539 packets/sec
     254675070 packets input, 95687414119 bytes, 0 no buffer
     Received 219458 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 215127 multicast, 0 pause input
     248063195 packets output, 69304150380 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     4320 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
-------------------------------------------------------------------------

 

Router#sh int gi0/1 switching
GigabitEthernet0/1 ## To Customer LAN ##
          Throttle count          1
                   Drops         RP          1         SP          0
             SPD Flushes       Fast          0        SSE          0
             SPD Aggress       Fast          0
            SPD Priority     Inputs          0      Drops          0

    Protocol  IP
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process    4942282  351308330    3318353  251134393
            Cache misses          0          -          -          -
                    Fast 2723729330 1182856208773 2588069178 720679718936
               Auton/SSE          0          0          0          0

    Protocol  DEC MOP
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process          0          0       3501     269577
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    Protocol  ARP
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process      61525    3691500      26317    1579020
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    Protocol  Other
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process      35024   17161760     210174   12610440
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

--------------------------------------------------------------------------------------

 

BTW,what is the meaning of "Throttle" when using "sh int [interface] switching"

 

Router# sh int gi0/0 switching
GigabitEthernet0/0 ## To ##
          Throttle count        767
                   Drops         RP       1132         SP          0
             SPD Flushes       Fast          0        SSE          0
             SPD Aggress       Fast          0
            SPD Priority     Inputs          1      Drops          0
 

 

Thanks a lot in advance.

 

Everyone's tags (3)
3 REPLIES
Super Bronze

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Posting

Unsure same applies to interface cache buffers, but in documentation for router buffers, a buffer cache miss just means a buffer needed to allocated.  No buffer should indicate a packet drop as a buffer was not immediately availalble (a hit miss) or couldn't be allocated at all (a cache miss).  I.e. other then perhaps slower perforamnce, waiting for a buffer allocation, not something to be worried about.

 

Re: throttle

https://learningnetwork.cisco.com/thread/55975

https://supportforums.cisco.com/discussion/9522611/throttles-ethernet

New Member

Thanks for the information,

Thanks for the information, Joseph.

This is a WAN router and it only has one WAN interface and one LAN interface. What goes in the WAN , must go out from the LAN and vice versa.

But why only Gi0/1(LAN interface) keep increasing "misses in cache", yet Gi(0/0) doesn't?

And is there a way to tune the buffer of the interface ?

Thanks in advance.

 

 

Super Bronze

DisclaimerThe Author of this

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Although you note you have just a single LAN and WAN interface, my guess would be cache misses might be caused by microbursts.

 

I don't know of a away to "tune" interface buffers.

 

If you believe this is an issue, contact TAC.

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