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High CPU usage for Catalyst 3750X on IP Input proccess

Dago_O
Level 1
Level 1

Dear Community members,

 

I need your advise for troubleshooting a high CPU usage problem on a Catalyst 3750X L3 switch, which is the core one in my network.  This problem is producing high latency and data lost that is driving my network slow and unstable.

So, the evidence.  This is the output of "show proc cpu sorted" command

 

#show proc cpu sorted
CPU utilization for five seconds: 98%/28%; one minute: 99%; five minutes: 99%
 PID Runtime(ms)     Invoked      uSecs   5Sec   1Min   5Min TTY Process
 214    41003600    13944778       2940 24.15% 25.21% 25.35%   0 IP Input         
 169    34067372     3928624       8671 16.31% 14.55% 14.37%   0 Hulc LED Process
 232    20500311     2892288       7087  8.95%  8.43%  8.43%   0 Spanning Tree    
 125    19816534     4237944       4675  5.59%  7.24%  7.74%   0 hpm main process
  12     3744640     2199415       1702  2.87%  2.56%  2.45%   0 ARP Input        
  85     1858596      630601       2947  1.27%  0.95%  0.89%   0 RedEarth Tx Mana
 129     2207888      176060      12540  0.95%  1.04%  1.03%   0 hpm counter proc
 212     2836209      795249       3566  0.79%  1.46%  1.32%   0 IP ARP Adjacency
  53      137483        4075      33738  0.79%  0.09%  0.06%   0 Per-minute Jobs  
 245      608854      166106       3665  0.79%  0.64%  0.54%   0 PI MATM Aging Pr
 121       68235       11682       5841  0.63%  0.07%  0.01%   0 Strider Tcam Mem
  91     1099121       68040      16154  0.47%  0.52%  0.48%   0 Adjust Regions   
 340      471153      649411        725  0.31%  0.27%  0.23%   0 VLAN Manager     
  84      686262      849745        807  0.31%  0.34%  0.36%   0 RedEarth I2C dri
  51      278373     3518118         79  0.31%  0.30%  0.28%   0 Net Input        
 170      398886      133716       2983  0.15%  0.14%  0.15%   0 HL3U bkgrd proce

As you can see, the CPU is completely utilized and the top process is IP Input.  Googleing I learned that the idea is to use interrupt-level switching (Fast,CEF, between others) instead of proccess-level one, so there is no CPU payload on switching.  Checking this...


#show cef interface brief
Interface                       IP-Address      Status  Switching               
Vlan1                           10.100.10.1     up      no dCEF                 
FastEthernet0                   unassigned      down    no dCEF                 
GigabitEthernet1/0/1            unassigned      up      CEF                     
GigabitEthernet1/0/2            unassigned      down    CEF                     
GigabitEthernet1/0/3            unassigned      up      CEF                     
GigabitEthernet1/0/4            unassigned      up      CEF                     
GigabitEthernet1/0/5            unassigned      up      CEF                     
GigabitEthernet1/0/6            unassigned      up      CEF                     
GigabitEthernet1/0/7            unassigned      up      CEF                     
GigabitEthernet1/0/8            unassigned      down    CEF                     
GigabitEthernet1/0/9            unassigned      up      CEF                     
GigabitEthernet1/0/10           unassigned      down    CEF                     
GigabitEthernet1/0/11           unassigned      up      CEF                     
GigabitEthernet1/0/12           unassigned      up      CEF                     
GigabitEthernet1/0/13           unassigned      up      CEF                     
GigabitEthernet1/0/14           unassigned      up      CEF                     
GigabitEthernet1/0/15           unassigned      up      CEF                     
GigabitEthernet1/0/16           unassigned      up      CEF                     
GigabitEthernet1/0/17           unassigned      up      CEF                     
GigabitEthernet1/0/18           unassigned      up      CEF                     
GigabitEthernet1/0/19           unassigned      up      CEF                     
GigabitEthernet1/0/20           unassigned      up      CEF                     
GigabitEthernet1/0/21           unassigned      up      CEF                     
GigabitEthernet1/0/22           unassigned      up      CEF                     
GigabitEthernet1/0/23           unassigned      up      CEF                     
GigabitEthernet1/0/24           unassigned      up      CEF                     
GigabitEthernet1/1/1            unassigned      down    CEF                     
GigabitEthernet1/1/2            unassigned      down    CEF                     
GigabitEthernet1/1/3            unassigned      down    CEF                     
GigabitEthernet1/1/4            unassigned      down    CEF                     
TenGigabitEthernet1/1/1         unassigned      down    CEF                     
TenGigabitEthernet1/1/2         unassigned      down    CEF                     
Null0                           unassigned      up      no CEF                  
Vlan2                           X.X.171.126  up      CEF                     
Vlan3                           unassigned      up      CEF                     
Vlan4                           unassigned      up      CEF                     
Vlan6                           X.X.165.65   up      CEF                     
Vlan7                           X.X.166.190  up      CEF                     
Vlan8                           X.X.152.2    up      CEF                     
Vlan9                           X.X.166.62   up      CEF                     
Vlan10                          unassigned      up      CEF                     
Vlan12                          X.X.161.126  up      CEF                     
Vlan13                          X.X.171.254  up      CEF                     
Vlan14                          X.X.167.254  up      CEF                     
Vlan15                          X.X.166.65   up      CEF                     
Vlan16                          unassigned      up      CEF                     
Vlan17                          X.X.167.62   up      CEF                     
Vlan19                          X.X.161.190  up      CEF                     
Vlan21                          X.X.167.126  up      CEF                     
Vlan22                          X.X.171.158  up      CEF                     
Vlan27                          X.X.162.226  up      CEF                     
Vlan28                          X.X.162.242  up      CEF                     
Vlan30                          10.201.6.67     up      CEF                     
Vlan60                          192.168.60.1    up      CEF                     
Vlan61                          unassigned      up      CEF                     
Vlan100                         192.168.100.1   up      CEF                     
Vlan200                         unassigned      up      CEF                     
Vlan201                         unassigned      up      CEF                     
Vlan240                         X.X.168.253  up      no dCEF                 
Vlan250                         X.X.171.190  up      CEF                     
Vlan251                         192.168.101.1   up      CEF                     
Vlan252                         192.168.102.1   up      CEF                     
Vlan253                         192.168.103.30  up      CEF                     
Vlan260                         X.X.162.190  up      CEF                     
Vlan280                         unassigned      up      CEF                     
Vlan281                         unassigned      down    CEF                     
Vlan298                         unassigned      down    CEF                     
Vlan301                         unassigned      down    CEF                     
StackPort1                      unassigned      down    CEF                     
Virtual1                        unassigned      up      -                       
Virtual2                        unassigned      up      -    

I can see that CEF is enabled on almost every interface, but checking "show interface switching" (output cropped for readability)

#show interface switching  
Vlan1
          Throttle count          0
                   Drops         RP       1139         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     339540   75121303      57097    4611829
            Cache misses          0          -          -          -
                    Fast          0          0         11       1053
               Auton/SSE          0          0          0          0

    Protocol  ARP                 
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process    1596666   95800784      72413    4344780
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    NOTE: all counts are cumulative and reset only after a reload.
Vlan2

    Protocol  IP                  
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process    2816137  201283125      10400    1470747
            Cache misses          0          -          -          -
                    Fast       1205     183277         10       2542
               Auton/SSE          0          0          0          0

    Protocol  ARP                 
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process     132743    7964580      86383    5182980
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    NOTE: all counts are cumulative and reset only after a reload.
Vlan3

    Protocol  ARP                 
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process      68260    4095600          0          0
            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          2        120          0          0
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    NOTE: all counts are cumulative and reset only after a reload.
Vlan4

    All statistics for this interface are zero.
Vlan6
          Throttle count          0
                   Drops         RP          9         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    5140914  356471282      23015    2993665
            Cache misses          0          -          -          -
                    Fast        428      39212          6       1135
               Auton/SSE          0          0          0          0

    Protocol  ARP                 
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process      13803     828180      16550     993000
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    NOTE: all counts are cumulative and reset only after a reload.
Vlan7

    Protocol  IP                  
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process     151934   14734706       7539    1527065
            Cache misses          0          -          -          -
                    Fast        156      14866          6       1315
               Auton/SSE          0          0          0          0

    Protocol  ARP                 
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process      10696     641760       9251     555060
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    NOTE: all counts are cumulative and reset only after a reload.
Vlan8
          Throttle count          0
                   Drops         RP      53150         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   76358777 5367493319     759413   66953170
            Cache misses          0          -          -          -
                    Fast     110151   10095563         74      13479
               Auton/SSE          0          0          0          0

    Protocol  ARP                 
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process     779028   46741694     459708   27582480
            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        127       7620          0          0
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    NOTE: all counts are cumulative and reset only after a reload.

 

... I notice that almost all the switching is done by process, so I don't know how to work around this.

To put into context.  This switch connect directly or indirectly almost 190 other devices, between switches (2960s, 2950s, 3560, and 3750) and access points.  It is the default gateway for a lot of VLAN and directly connect our WAN access. 

The switch is running IOS 12.2(58)SE2.  I have red that in other post (lik this one https://supportforums.cisco.com/discussion/11628666/cisco-3750x-24se-12258se2-cpu-utilization-high) that it's advice to to downgrade to 12.2(55)SE8 for stability reason, but this post is 3 years old so I'd like to know if this remains as a valid solution or is another preferable IOS version to work around this problem.

From the "show proc cpu" command I can see other 2 proccess eating CPU resource, HULC LED and Spanning Tree, but I'd like to troubleshoot the IP Input one first, cause is the top most one.

Please, advise for where should I look for solving this problem.

Thanks very much.

30 Replies 30

Hi Dago,

You could also configure Dynamic ARP inspection on the switch to overcome this situation. Please refer to the document in the link below:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/troubleshooting/cpu_util.html#wp1003452

Following is the link to the config guie of this feature:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_55_se/configuration/guide/3750xscg/swdynarp.html

HTH,

Roopa

roor
Cisco Employee
Cisco Employee

Hi Martin,

I dont think broadcast storm control rate limits CPU bound traffic like ARP. I think it does it for data traffic.

Another feature apart from DAI Referenced above , that can be used to ratelimit arp is the protocol storm protection feature. Please take a look at the link below.

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_58_se/configuration/guide/3750xscg/swtrafc.html#pgfId-1173343

Regards,

Roopa

How many link flapping messages are you getting?  A few from wireless clients (or even wired ones) isn't an issue, but a lot might indicate a loop that STP can't resolve.  I've seen a hub accidentally connected to 2 separate network ports that can cause serious problems.

Guys, thanks for the advice for ARP issue resolution, but I must say that somehow I  made a mistake (or wireshark had some trouble polting data .... don't know), but after notice some strange behavior whit plotted IO graph (some values remained the same even after changing it filter), I reopened wireshark and reloaded capture file and then ARP package wasn't as high as I reported.  Atached is the Protocl Hierarchy which show very few ARP traffic and a lot of RTSP (from IP surviliance cameras .... will check on that latter).

How many link flapping messages are you getting?  A few from wireless clients (or even wired ones) isn't an issue, but a lot might indicate a loop that STP can't resolve.  I've seen a hub accidentally connected to 2 separate network ports that can cause serious problems

Sometimes there is no MACFLAP messages, they aren't constant, but if I do a "show log" mostly the only thing I can see are those one.  They all came from wifi clients.  There is no HUB on our network, just switches, all with SPT capability.

Will keep on searching for the couse of my problem.

Thanks.

It's worth checking where all the RSTP packets are coming from.

If the TCNs are coming from ports connected to end clients then make sure you have enabled "spanning-tree portfast" for access ports.

But don't enable it on any switch to switch connections.

If there a lot of TCNs being generated, for whatever reason, then this will cause your switch to flush it's mac addresses tables which will mean traffic is flooded until the mac addresses are learnt again.

Jon

You can use this commanmd to help narrow down where STP loops are coming from in a Cisco network in case thats the issue

sh spanning-tree detail | i ieee|occur|from|is exec

So .... I still running this problem and bosses are starting to press me up :(

What we have done and notice this las tieme

We did a IOS downgrade from 12.2(58)SE2 to 12.2.(55)SE10.  Althought we noticed a "base" consumption decrease during non-work hours, didn't solve the issue, couse during work hours CPU hit 99-100% utilization, so we assume this is not a IOS bug problem.

After downgrading we started geting this log message. 

Nov 13 18:22:41.462: %PLATFORM_ENV-1-FRU_PS_ACCESS: FRU Power Supply is not responding

I know this is not related to CPU utilization, but if anyone can point out what is about.  Some guy on another forum advise to upgrade to IOS v15 becouse of this message     ¬¬U

Checking Input Queue Drops I'm getting this

#show controllers cpu-interface
.
.
.
cpu-queue-frames  retrieved  dropped    invalid    hol-block  stray
----------------- ---------- ---------- ---------- ---------- ----------
rpc               0          0          0          0          0
stp               8734828    0          0          0          0
ipc               0          0          0          0          0
routing protocol  361277676  0          0          0          0
L2 protocol       715921     0          0          0          0
remote console    0          0          0          0          0
sw forwarding     1105974    0          0          0          0
host              65489122   0          0          0          0
broadcast         145536630  0          0          0          0
cbt-to-spt        0          0          0          0          0
igmp snooping     219056228  0          0          0          0
icmp              186191930  0          0          0          0
logging           0          0          0          0          0
rpf-fail          0          0          0          0          0
dstats            0          0          0          0          0
cpu heartbeat     5453326    0          0          0          0

cpu-queue         static inuse static added
----------------- ------------ ------------
rpc               0            0
stp               0            0
ipc               0            0
routing protocol  0            0
L2 protocol       0            0
remote console    0            0
sw forwarding     0            0
host              0            0
broadcast         0            0
cbt-to-spt        0            0
igmp snooping     0            0
icmp              0            0
logging           0            0
rpf-fail          0            0
dstats            0            0
cpu heartbeat     0            0



#show buffers
Buffer elements:
     1061 in free list (500 max allowed)
     237838781 hits, 0 misses, 1024 created

Public buffer pools:
Small buffers, 104 bytes (total 84, permanent 50, peak 209 @ 3d05h):
     78 in free list (20 min, 150 max allowed)
     115746099 hits, 95 misses, 227 trims, 261 created
     0 failures (0 no memory)
Middle buffers, 600 bytes (total 34, permanent 25, peak 177 @ 3d03h):
     25 in free list (10 min, 150 max allowed)
     1930057 hits, 752 misses, 369 trims, 378 created
     125 failures (0 no memory)
Big buffers, 1536 bytes (total 50, permanent 50, peak 77 @ 3d05h):
     50 in free list (5 min, 150 max allowed)
     1318164 hits, 9 misses, 27 trims, 27 created
     0 failures (0 no memory)
VeryBig buffers, 4520 bytes (total 16, permanent 10, peak 16 @ 3d05h):
     1 in free list (0 min, 100 max allowed)
     73 hits, 3 misses, 28 trims, 34 created
     0 failures (0 no memory)
Large buffers, 5024 bytes (total 0, permanent 0):
     0 in free list (0 min, 10 max allowed)
     0 hits, 0 misses, 0 trims, 0 created
     0 failures (0 no memory)
Huge buffers, 18024 bytes (total 0, permanent 0):
     0 in free list (0 min, 4 max allowed)
     0 hits, 0 misses, 0 trims, 0 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)
     227879 hits, 33 misses
RxQ1 buffers, 2040 bytes (total 128, permanent 128):
     0 in free list (0 min, 128 max allowed)
     8002569 hits, 774927 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):
     0 in free list (0 min, 128 max allowed)
     242385008 hits, 119511351 fallbacks
RxQ4 buffers, 2040 bytes (total 128, permanent 128):
     0 in free list (0 min, 128 max allowed)
     716488 hits, 21290530 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)
     1106795 hits, 1179012 misses
RxQ7 buffers, 2040 bytes (total 192, permanent 192):
     55 in free list (0 min, 192 max allowed)
     65557510 hits, 5927947 misses
RxQ8 buffers, 2040 bytes (total 64, permanent 64):
     0 in free list (0 min, 64 max allowed)
     145678354 hits, 274164627 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):
     1 in free list (0 min, 64 max allowed)
     215847135 hits, 3575586 fallbacks
RxQ11 buffers, 2040 bytes (total 16, permanent 16):
     0 in free list (0 min, 16 max allowed)
     186217703 hits, 186383864 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):
     0 in free list (0 min, 4 max allowed)
     5456770 hits, 5456766 misses
HRPCRespFallback buffers, 1500 bytes (total 80, permanent 80):
     80 in free list (0 min, 80 max allowed)
     0 hits, 0 misses
RxQFB buffers, 2040 bytes (total 904, permanent 904):
     858 in free list (0 min, 904 max allowed)
     123328761 hits, 534252 misses
RxQ0 buffers, 2040 bytes (total 1200, permanent 1200):
     700 in free list (0 min, 1200 max allowed)
     500 hits, 0 misses
IPC buffers, 2048 bytes (total 300, permanent 300):
     296 in free list (150 min, 500 max allowed)
     36908 hits, 0 fallbacks, 0 trims, 0 created
     0 failures (0 no memory)
Jumbo buffers, 9240 bytes (total 200, permanent 200):
     200 in free list (0 min, 200 max allowed)
     0 hits, 0 misses

Header pools:

I can see that there is a lot of droped (misses) packages on almost any queue.

#show int | include Vlan|Input|Giga
Vlan1 is up, line protocol is up
  Input queue: 1/75/5/0 (size/max/drops/flushes); Total output drops: 0
Vlan2 is up, line protocol is up
  Input queue: 10/75/173/0 (size/max/drops/flushes); Total output drops: 0
Vlan3 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan4 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan6 is up, line protocol is up
  Input queue: 17/75/4/0 (size/max/drops/flushes); Total output drops: 0
Vlan7 is up, line protocol is up
  Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan8 is up, line protocol is up
  Input queue: 166/75/37691/0 (size/max/drops/flushes); Total output drops: 0
Vlan9 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan10 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan12 is up, line protocol is up
  Input queue: 11/75/3/0 (size/max/drops/flushes); Total output drops: 0
Vlan13 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan14 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan15 is up, line protocol is up
  Input queue: 8/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan16 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan17 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan19 is up, line protocol is up
  Input queue: 7/75/864/0 (size/max/drops/flushes); Total output drops: 0
Vlan21 is up, line protocol is up
  Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan22 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan27 is up, line protocol is up
  Input queue: 34/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan28 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan30 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan60 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan61 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan100 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan200 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan201 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan240 is administratively down, line protocol is down
  Input queue: 0/75/17/0 (size/max/drops/flushes); Total output drops: 0
Vlan250 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan251 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan252 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan253 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan260 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan280 is up, line protocol is up
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan281 is down, line protocol is down
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan298 is down, line protocol is down
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Vlan301 is down, line protocol is down
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/1 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8481 (bia 10f3.11ca.8481)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/2 is administratively down, line protocol is down (disabled)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8482 (bia 10f3.11ca.8482)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/3 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8483 (bia 10f3.11ca.8483)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/4 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8484 (bia 10f3.11ca.8484)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/5 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8485 (bia 10f3.11ca.8485)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/6 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8486 (bia 10f3.11ca.8486)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/7 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8487 (bia 10f3.11ca.8487)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/8 is administratively down, line protocol is down (disabled)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8488 (bia 10f3.11ca.8488)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/9 is down, line protocol is down (notconnect)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8489 (bia 10f3.11ca.8489)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 31817
GigabitEthernet1/0/10 is down, line protocol is down (notconnect)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.848a (bia 10f3.11ca.848a)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 55
GigabitEthernet1/0/11 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.848b (bia 10f3.11ca.848b)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/12 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.848c (bia 10f3.11ca.848c)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/13 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.848d (bia 10f3.11ca.848d)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/14 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.848e (bia 10f3.11ca.848e)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 24708
GigabitEthernet1/0/15 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.848f (bia 10f3.11ca.848f)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/16 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8490 (bia 10f3.11ca.8490)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/17 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8491 (bia 10f3.11ca.8491)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/18 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8492 (bia 10f3.11ca.8492)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/19 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8493 (bia 10f3.11ca.8493)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/20 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8494 (bia 10f3.11ca.8494)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/21 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8495 (bia 10f3.11ca.8495)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 3005
GigabitEthernet1/0/22 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8496 (bia 10f3.11ca.8496)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
GigabitEthernet1/0/23 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8497 (bia 10f3.11ca.8497)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 56
GigabitEthernet1/0/24 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10f3.11ca.8498 (bia 10f3.11ca.8498)
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

I can see that VLAN 8 and G1/0/14 are getting a lot of dorps

You can use this commanmd to help narrow down where STP loops are coming from in a Cisco network in case thats the issue

sh spanning-tree detail | i ieee|occur|from|is exec

#sh spanning-tree detail | i ieee|occur|from|is exec
 VLAN0001 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 116 last change occurred 00:19:30 ago
          from GigabitEthernet1/0/1
 VLAN0002 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:30 ago
          from GigabitEthernet1/0/1
 VLAN0003 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 52 last change occurred 00:19:30 ago
          from GigabitEthernet1/0/1
 VLAN0004 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:30 ago
          from GigabitEthernet1/0/1
 VLAN0005 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:31 ago
          from GigabitEthernet1/0/1
 VLAN0006 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:31 ago
          from GigabitEthernet1/0/1
 VLAN0007 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:31 ago
          from GigabitEthernet1/0/1
 VLAN0008 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:31 ago
          from GigabitEthernet1/0/1
 VLAN0009 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:31 ago
          from GigabitEthernet1/0/1
 VLAN0010 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:31 ago
          from GigabitEthernet1/0/1
 VLAN0012 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 115 last change occurred 00:19:32 ago
          from GigabitEthernet1/0/1
 VLAN0013 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 55 last change occurred 00:19:32 ago
          from GigabitEthernet1/0/1
 VLAN0014 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:32 ago
          from GigabitEthernet1/0/1
 VLAN0015 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:32 ago
          from GigabitEthernet1/0/1
 VLAN0016 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 77 last change occurred 00:19:32 ago
          from GigabitEthernet1/0/1
 VLAN0017 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:32 ago
          from GigabitEthernet1/0/1
 VLAN0018 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:32 ago
          from GigabitEthernet1/0/1
 VLAN0019 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 39 last change occurred 00:19:33 ago
          from GigabitEthernet1/0/1
 VLAN0020 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 31 last change occurred 04:02:05 ago
          from GigabitEthernet1/0/7
 VLAN0021 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:33 ago
          from GigabitEthernet1/0/1
 VLAN0022 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:33 ago
          from GigabitEthernet1/0/1
 VLAN0023 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 54 last change occurred 00:19:34 ago
          from GigabitEthernet1/0/1
 VLAN0024 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 12 last change occurred 00:19:34 ago
          from GigabitEthernet1/0/1
 VLAN0027 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:34 ago
          from GigabitEthernet1/0/1
 VLAN0028 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 34 last change occurred 00:19:34 ago
          from GigabitEthernet1/0/1
 VLAN0030 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:35 ago
          from GigabitEthernet1/0/1
 VLAN0040 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:35 ago
          from GigabitEthernet1/0/1
 VLAN0051 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 35 last change occurred 00:19:35 ago
          from GigabitEthernet1/0/1
 VLAN0060 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:35 ago
          from GigabitEthernet1/0/1
 VLAN0061 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 35 last change occurred 00:19:35 ago
          from GigabitEthernet1/0/1
 VLAN0062 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 35 last change occurred 00:19:35 ago
          from GigabitEthernet1/0/1
 VLAN0063 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 34 last change occurred 00:19:35 ago
          from GigabitEthernet1/0/1
 VLAN0100 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:35 ago
          from GigabitEthernet1/0/1
 VLAN0200 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 97 last change occurred 00:19:36 ago
          from GigabitEthernet1/0/1
 VLAN0201 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 84 last change occurred 00:19:36 ago
          from GigabitEthernet1/0/1
 VLAN0202 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 83 last change occurred 00:19:36 ago
          from GigabitEthernet1/0/1
 VLAN0203 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 85 last change occurred 00:19:36 ago
          from GigabitEthernet1/0/1
 VLAN0204 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:37 ago
          from GigabitEthernet1/0/1
 VLAN0205 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:37 ago
          from GigabitEthernet1/0/1
 VLAN0206 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:37 ago
          from GigabitEthernet1/0/1
 VLAN0210 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 203 last change occurred 00:19:37 ago
          from GigabitEthernet1/0/1
 VLAN0211 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 111 last change occurred 00:19:38 ago
          from GigabitEthernet1/0/1
 VLAN0213 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 39 last change occurred 00:19:38 ago
          from GigabitEthernet1/0/1
 VLAN0214 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:38 ago
          from GigabitEthernet1/0/1
 VLAN0215 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:38 ago
          from GigabitEthernet1/0/1
 VLAN0220 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:38 ago
          from GigabitEthernet1/0/1
 VLAN0230 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:38 ago
          from GigabitEthernet1/0/1
 VLAN0237 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:38 ago
          from GigabitEthernet1/0/1
 VLAN0238 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:39 ago
          from GigabitEthernet1/0/1
 VLAN0240 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 45 last change occurred 00:19:39 ago
          from GigabitEthernet1/0/1
 VLAN0241 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 32 last change occurred 00:19:39 ago
          from GigabitEthernet1/0/1
 VLAN0242 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:39 ago
          from GigabitEthernet1/0/1
 VLAN0250 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:39 ago
          from GigabitEthernet1/0/1
 VLAN0251 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:40 ago
          from GigabitEthernet1/0/1
 VLAN0252 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 53 last change occurred 00:19:40 ago
          from GigabitEthernet1/0/1
 VLAN0253 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:40 ago
          from GigabitEthernet1/0/1
 VLAN0260 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:40 ago
          from GigabitEthernet1/0/1
 VLAN0280 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 35 last change occurred 00:19:40 ago
          from GigabitEthernet1/0/1
 VLAN0290 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 36 last change occurred 00:19:40 ago
          from GigabitEthernet1/0/1
 VLAN0291 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:40 ago
          from GigabitEthernet1/0/1
 VLAN0292 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 37 last change occurred 00:19:41 ago
          from GigabitEthernet1/0/1
 VLAN0299 is executing the ieee compatible Spanning Tree protocol
  Number of topology changes 38 last change occurred 00:19:41 ago
          from GigabitEthernet1/0/1

What I can see with this output is that there is a lot of TCN and most of them come from G1/0/7 which happen to be the interface that generate most of the CPU utilization (if I shutdown the interface CPU goes down).

If the TCNs are coming from ports connected to end clients then make sure you have enabled "spanning-tree portfast" for access ports.

But don't enable it on any switch to switch connections

That's what we do :)

Any advice on how can I proceede?

Thanks ;)

You need to run that spanning-tree command a few times to see if the TCN count is increasing and how fast.

All the TCNs are coming from the same port.

If it is a switch connected to that port you need to run the same command on there and work out what is generating them.

It may not be STP but if you are seeing a lot of RSTP traffic you need to work out why.

Jon

Dago

I think that becouse of so high level of CPU and Interrupts,your 3750 has no ability to send BPDUs to other devices in correct timing periods,or worse maybe missed to send some.If there is 100% link utilization on some ports,then some BPDUs cant reach lower levels.And ther you go,then all of that TCN are just consequence to that.

But first of all,you must decide which device was suppose to be--root--in your network and on that device you must set highest priority.

You must find out,which traffic is compromise your CPU,after lowering those CPU,it will maybe everything settle down include those TCNs.

I would suggest to use these commands

show controllers utilization   to see from where is coming most of traffic.If you see 80-100% utilization on some interface,then use wireshark and analyize traffic.Use Statistic--IOgraph and in filter line wrote  arp,icmp,stp

show mac address-table count | inc Available  to see how many MACs are in table

clear counters

and then use

show interfaces accounting | inc ARP|Vlan    to see how many ARPs are on some interfaces.And IF there is a lot of them on some explicite interface,then look with wireshark in these interface and see who is the source of them,and then find out why.

If there is problem with ICMP which may be very annoying,you can discover  that on Controllers Queues.I wrote down this in my upper post,where I mention Debug.Whith debug tool,you must be very carefull and follow those instruction line by line.They are writen in those cisco article in my post,below your post.

I hope that you will soon find out what is happening in your network and solve the problem

BR

Hi Dago,

i think, you need verify / reconfiguring STP and on all switches. make sure your network having root of the STP. After you decide on the root switch, set the appropriate variables to designate the switch as the root switch. The only variable that you must set is the bridge priority. If the switch has a bridge priority that is lower than all the other switches, the other switches automatically select the switch as the root switch.

Note: Remember that one root switch is identified per-VLAN

You can also issue the set spantree portfast command, on a per-port basis.However, do not use this command when you have switch-to-switch connection. In this case, the command can result in a loop.

based on log spanning-tree details, you have a lot of number the topology changes.STP Path Cost Automatically Changes When a Port Speed/Duplex Is Changed. STP calculates the path cost based on the media speed (bandwidth) of the links between switches and the port cost of each port forwarding frame. Spanning tree selects the root port based on the path cost. The port with the lowest path cost to the root bridge becomes the root port. The root port is always in the forwarding state.


If the speed/duplex of the port is changed, spanning tree recalculates the path cost automatically. A change in the path cost can change the spanning tree topology.

Recommendation, set manually speed / duplex on each all interface. 

for analysis, go to output interpreter tool cisco. put your show tech log before.

Regards, Habibi

Make a few more discovery with command which you already use--show controllers cpu-interface

Then compare the counters result on each Queue--stp,icmp,hosts etc

Where you see a lot of counter differences,that is the reason for a higher CPU&Interrupts--but you could have a few of them.Go step by step.

When you see what is cause your problem go for Debug.

It,s all well writen in this article and it always help me to solve the high cpu problems on my 3750G or X.

Article.Read carefuly and go step by step--you cant fail.

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/troubleshooting/cpu_util.html

Hello

You might want to configure broadcast storm-control on the port where you're receiving the ARP queries, to limit the number of broadcast ARP queries that you have to process. Have a look at this link: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_53_se/configuration/guide/3750xscg/swtrafc.html#wp1063295

Best regards,
Martin

Ok Leo.  Thanks.  I'll consider this downgrade.  What do you think about 15.0(2)SE8?  As roor suggested that one.

What do you think about 15.0(2)SE8?

I can't comment on 15.0(2)SE8 running on 3750X.  15.0(2)SE8 works well with 2960S and I'm testing this version on 3560CG but I've been burnt with 15.0(2)SE train before plus the 3750X sits in a site distribution level.  I ain't going to risk it again.  

Hi Dago,

 

should be ip route-cache enabled on interface vlan 240. for this case if you disable ip route-cache maybe impact to CPU. i had experience with same case before, and then i trying to enable ip route-cache on each interface (by default the services is enabled on interface).

why you should enabled "ip route-cache" on interface because on your switch for "ip routing" activated.

my assumption, if you want layer 3 services on your switches. Do not disable ip route-cache on each interface.

 

try this on interface vlan 240

interface Vlan240
 ip address X.X.168.253 255.255.255.0
 default ip route-cache cef
 default ip route-cache

 

Regards, Habibi
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