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Community Member

3750x Hulc LED Process


I'm facing problem in the CPU Utilization on Cisco 3750x, the below is the resault of "show process cpu sorted":

  5Sec         1Min         5Min            TTY Process

16.47%    16.93%       17.03%          Hulc LED Process

how i can minimze the CPU Utilziation for this process. I'm using to SFP interface only.

This normal behavior or i can optimize that ?

the version on switch: c3750e-universalk9-mz.122-58.SE2.bin

Best Regards


Community Member

3750x Hulc LED Process


I have the same problem with most of our 3750X

CPU utilization for five seconds: 44%/1%; one minute: 44%; five minutes: 44%

PID Runtime(ms)     Invoked      uSecs   5Sec   1Min   5Min TTY Process

179   367617815    42704985       8608 19.77% 19.58% 19.46%   0 Hulc LED Process

Soft is

Switch Ports Model              SW Version            SW Image                

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

*    1 54    WS-C3750X-48P      15.0(2)SE4            C3750E-UNIVERSALK9-M    

     2 54    WS-C3750X-48P      15.0(2)SE4            C3750E-UNIVERSALK9-M    

     3 54    WS-C3750X-48P      15.0(2)SE4            C3750E-UNIVERSALK9-M    

Best Regards


Hall of Fame Super Silver

3750x Hulc LED Process

The Hulc LED process accounting for a fairly significant amount of switch CPU resources is not at all unusual. There are numerous threads here on CSC about this exact issue going back several years.

It has waxed and waned with varying IOS releases but has been around for at least four years. The conclusion that most folks come to is that it's normal behavior. (Sandeep's explanation here is the best one I've seen.) The LED process, among other things, is constantly scanning the ports' link status, system environment and other things and is pretty much the background workhorse on the switch.

Unless and until you have other process which, when added to the CPU load caused by the LED process, push your switch's CPU to the point of dropping traffic it is generally not an issue.

Hall of Fame Super Blue

3750x Hulc LED Process

Hmmmmm ... 3750X ... with PoE.

If you are running PoE and/or 802.1x, it's best to AVOID 15.0.  This means even the one you are running.

Consider 12.2(55)SE8.  All my 3750 fleet are running this version and I have both PoE & 802.1x. 

Community Member

3750x Hulc LED Process

Thanks Marvin for your support.

yes Leo I'm using the POE because we have Telephony on our Network.

Best regards

Nadeem Saleem

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