[c-nsp] 3550 high cpu & process switched traffic

[Jon Lewis]

I just checked several of ours (3550-48s), and we also seem to be process 
switching most traffic, but the CPU load is negligible (4%).  I have to 
wonder if this is counter buggery.  Even ones that are strictly being used 
as L2 switches show all traffic (input and output) as process switched. 
The ones doing a mix of L2/L3 show some traffic route cache switched, but 
mostly processor switched.

On Fri, 18 Aug 2006, Rodney Dunn wrote:

> Something is wrong.
>
> What is the config?
>
> I'm not too good with the 3550 as that is a L3 capable switch.
>
> But usually it's a feature of some sort configured causing it.
>
> On Fri, Aug 18, 2006 at 07:44:36PM +0300, Tassos Chatzithomaoglou wrote:
>> I have a 3550 (12.1(22)EA8) which is constantly showing high cpu usage :
>>
>> 3550#sh proc cpu
>> CPU utilization for five seconds: 99%/96%; one minute: 97%; five minutes: 97%
>>
>> If i'm not wrong, most of it is due to interrupts and i'm trying to find out what exactly is causing
>> this. The 3550 has 3 SVIs (1 for management), 6 routed interfaces (5 of them have mls qos
>> configured) and 2 L2 interfaces (one is trunk).
>>
>> Also I would like to ask if the following output (only processor used for eggress traffic on ALL
>> interfaces) is considered normal for 3550 switches:
>>
>> 3550#sh int stats
>> Vlan1
>>            Switching path    Pkts In   Chars In   Pkts Out  Chars Out
>>                 Processor        179      12172        179      10740
>>               Route cache          0          0          0          0
>>                     Total        179      12172        179      10740
>> Vlan4
>>            Switching path    Pkts In   Chars In   Pkts Out  Chars Out
>>                 Processor       2806     179584       2806     168360
>>               Route cache       8295     581139          0          0
>>                     Total      11101     760723       2806     168360
>> Vlan10
>>            Switching path    Pkts In   Chars In   Pkts Out  Chars Out
>>                 Processor   21993427 2785897656   20910415 2025707486
>>               Route cache 2289603255 1233480520          0          0
>>                     Total 2311596682 4019378176   20910415 2025707486
>> Interface FastEthernet0/1 is disabled
>>
>> FastEthernet0/2
>>            Switching path    Pkts In   Chars In   Pkts Out  Chars Out
>>                 Processor          0          0     718962  112668280
>>               Route cache          0          0          0          0
>>                     Total          0          0     718962  112668280
>> FastEthernet0/3
>>            Switching path    Pkts In   Chars In   Pkts Out  Chars Out
>>                 Processor      98405    6710609     535543   50002650
>>               Route cache 2288708113 1141208459          0          0
>>                     Total 2288806518 1147919068     535543   50002650
>> FastEthernet0/4
>>            Switching path    Pkts In   Chars In   Pkts Out  Chars Out
>>                 Processor      89343   11874108  396765671 2089412449
>>               Route cache  543340008 1149008067          0          0
>>                     Total  543429351 1160882175  396765671 2089412449
>>
>> ....
>>
>>
>> "sh int switching" shows the same problem for all interfaces : The Fast path has 0 entries for all
>> protocols including IP.
>>
>> Regards,
>> Tassos
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----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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