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Flapping HSRP
Hi guys, I know this is not a troubleshooting forum, but just thought I may share my problem with you and see what you think.
I have been having problems with a cat 6503 that is one of the core/distribution switches in the network. It is a basic switch block, two core/distribution switches connected to each other, with several access switches hooked up to them, by the way the access switches have no redundant conection to the core/distribution switches.
The problem
HSRP flapps spontaneusly two times a week, this 6503 starts claiming it is active, then it realizes the other core switch is up, and goes back to standby, then it claims its active again, and so on and on . The only way I can solve it is restarting the offending switch.
What have I done
I have done my homework, I have checked there are no physical problems on the link between the core switches, I replaced the single link that was connecting them with an etherchannel, using different FO cables and different ports on different cards, just to rule out a physical problem. show interface shows no errors or interface resets.
Next, I made sure there are no STP loops, I even run some spantree debugs when this flapping happened without any STP instabilities reported.
I also removed the preempt option, and still getting the flapping.
show process cpu history reports zero cpu utilization
Traffic is low, reported from show interface.
Any ideas?
I have been having problems with a cat 6503 that is one of the core/distribution switches in the network. It is a basic switch block, two core/distribution switches connected to each other, with several access switches hooked up to them, by the way the access switches have no redundant conection to the core/distribution switches.
The problem
HSRP flapps spontaneusly two times a week, this 6503 starts claiming it is active, then it realizes the other core switch is up, and goes back to standby, then it claims its active again, and so on and on . The only way I can solve it is restarting the offending switch.
What have I done
I have done my homework, I have checked there are no physical problems on the link between the core switches, I replaced the single link that was connecting them with an etherchannel, using different FO cables and different ports on different cards, just to rule out a physical problem. show interface shows no errors or interface resets.
Next, I made sure there are no STP loops, I even run some spantree debugs when this flapping happened without any STP instabilities reported.
I also removed the preempt option, and still getting the flapping.
show process cpu history reports zero cpu utilization
Traffic is low, reported from show interface.
Any ideas?
I hate pandas
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Netstudent
Member Posts: 1,693 ■■■□□□□□□□
Hey vegetable,
Have you tried looking at this whitepaper?
http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094afd.shtml#t1
It has some case studies with a similar symptoms of flapping states. If you haven't already checked it out, it might be worth a gander.
It talks about loss of successive HSRP packets due to spanning-tree instability and a few other case studies.There is no place like 127.0.0.1 BUT 209.62.5.3 is my 127.0.0.1 away from 127.0.0.1! -
OptionsCucumber
Member Posts: 192
Thats a very good doc, I had read another cisco doc, not as detailed as this one. I will give ita detailed look, btw, the network provider has not found the source of the problem neither.I hate pandas
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dtlokee
Member Posts: 2,378 ■■■■□□□□□□
More information would help understand and resolve the issues you're having.The only easy day was yesterday!