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Rising star

Switch is restarting from time to time

Hi All,

I noticed on of my switches on the Network is restarting periodically each 7 hours.

I Have checked the power & made sure that every thing is worked fine, this issue puzzled me for a lot of time,

please find bellow the output of (sh logg) command:-

Log Buffer (4096 bytes):

0Log Buffer (4096 bytes):

00:00:17: %LINK-5-CHANGED: Interface Vlan1, changed state to administratively do


00:00:17: %SYS-5-CONFIG_I: Configured from memory by console

00:00:18: %SYS-5-RESTART: System restarted --

Cisco Internetwork Operating System Software

IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(6)EA2c, RELEASE SOFTWARE


Copyright (c) 1986-2002 by cisco Systems, Inc.

Compiled Thu 28-Feb-02 14:44 by antonino

00:00:18: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state t

o down

00:00:20: %LINK-3-UPDOWN: Interface FastEthernet0/19, changed state to up

00:00:21: %LINK-3-UPDOWN: Interface FastEthernet0/2, changed state to up

00:00:21: %LINK-3-UPDOWN: Interface FastEthernet0/3, changed state to up

00:00:21: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up

00:00:21: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/19, chan

ged state to down

00:00:21: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up

00:00:21: %DTP-5-TRUNKPORTON: Port Fa0/19 has become dot1q trunk

00:00:22: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, chang

ed state to down

please find bellow the output of (sh stacks) command:-

Switch-2#sh stacks

Minimum process stacks:

Free/Size Name

4924/6000 calhoun_flash init

5592/6000 SPAN Subsystem

5584/6000 platform SPAN Subsystem

9504/12000 Init


8112/9000 DHCP Client

Interrupt level stacks:

Level Called Unused/Size Name

3 7994 7872/9000 StrataSwitch

4 2090 8712/9000 EIC intr

7 23233 8748/9000 Timer Interrupt Handler

Spurious interrupts: 1

Any help would be highly appreciated,



Could you show us the output of this command "sh ver | inc ystem returned"?



The sh ver | inc system returned is not supported on my switch, only (sh ver) command and bellow the output:-

Switch-2#sh version

Cisco Internetwork Operating System Software

IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(6)EA2c, RELEASE SOFTWARE


Copyright (c) 1986-2002 by cisco Systems, Inc.

Compiled Thu 28-Feb-02 14:44 by antonino

Image text-base: 0x80010000, data-base: 0x8042C000

ROM: Bootstrap program is CALHOUN boot loader

Bayanat-sw2 uptime is 1 hour, 18 minutes

System returned to ROM by power-on

System image file is "flash:c2950-i6q4l2-mz.121-6.EA2c.bin"

cisco WS-C2950-24 (RC32300) processor (revision C0) with 21295K bytes of memory

Processor board ID FOCX0711Z172

Last reset from system-reset

Running Standard Image

24 FastEthernet/IEEE 802.3 interface(s)

32K bytes of flash-simulated non-volatile configuration memory.

Base ethernet MAC Address: 00:0D:28:BF:DE:40

Motherboard assembly number: 73-5781-10

Power supply part number: 34-0965-01

Motherboard serial number: FOC07291RD9

Power supply serial number: PHI0146WATO

Model revision number: C0

Motherboard revision number: A0

Model number: WS-C2950-24

System serial number: FOCX0711Z172

Configuration register is 0xF


Any Ideas,



Hi Friend,

I got some information from the cisco output interpreter using the stack information which you posted.

Have a look at this

This device has reported 1 spurious interrupts. These interrupts occur

when an unnecessary interrupt is raised for an already processed packet, possibly

due to an internal race condition, or due to improper initialization of interrupt

handling routines. These may be caused either by defective hardware, or by software.

There is no discernable impact on the behavior of the router due to such spurious

interrupts. They are only counted for monitoring purposes. They may safely be ignored

as long as the number of spurious interrupts is not high and increasing, along

with some dropped packets or degraded performance.

For more information on spurious interrupts

HTH, if yes please rate the post.



Hi Ankur,

Ur post is helpfull, I red it but I am really wondering what is the suitable solution for such issue??



HI Friend,

As I see Spurious Interrupts you can first try upgrading the IOS on your BOX to the latest one in its train as continuous restart can be result of IOS bug.

If still the problem is not resolved I am afraid if it is a hardware failure. But before replacing hardware you can contact Cisco TAC is possible.

HTH, if yes please rate the post.




in addition to Ankur's post, from your first output it looks like your port FastEthernet0/19 is changed to trunk mode. Can you check what the port is supposed to be used for ? You might want to set it to either 'switchport mode trunk' and configure it with 'switchport nonegotiate' in order to disable any sort of DTP. Or, if the port is left to it's defaults, set it to 'switchport mode access', and check if the problem persists...



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