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Trouble with Cisco 6509 being used as router

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20 years 5 months ago #4263 by n8
I have been trying to figure out why every time i disconnect an interface on my 6509 and re-connect it, it takes 40 seconds for the interface to come back up.

The 6509 has a l3 routing module built into the supervisor module. I have a SUP1A. Port negotiation doesn't seem to make a difference.

Anyone else seen this?

Thanks,

N8
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20 years 5 months ago #4273 by huliyar
HI,

Though I won't be able to give you full detail about how it actually works, but i think that its due to STP convergence time that is taking place.

When you disconnect the link and reconnect, the port will be in blocking mode and it has to enter listening mode. Here two forward delay timer is used each 15 seconds.
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20 years 5 months ago #4275 by TheBishop
Replied by TheBishop on topic Port
I seem to remember that there are two Spanning Tree modes you can set a port into on Cisco. Fast Spanning Tree makes the port come up much faster. If that is featured on your device then it could be the issue
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20 years 5 months ago #4279 by Chris
I was thinking of the same Huliyar and Bishop.... a STP Problem.

The Bishop is also correct, there is a command that will bring the port up immediately. Enter the config mode and go to your interface, issue the "spanning-tree portfast" command.

With the spanning-tree portfast command, the switch will enable the interface and place it into 'FORWARD' mode, bypassing the usual STP procedure.

Note, when you issue the command, the router will warn you that this command should only be used when the interface is connect to a Host, and not another other switch, because looping problems can occur.

Let us know if this resolved your problem.

Cheers,

Chris Partsenidis.
Founder & Editor-in-Chief
www.Firewall.cx
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20 years 5 months ago #4286 by n8
Thanks for the feedback guys, I'll give it a shot. I didn't even think of STP. I'm too used to seeing all my other devices come up as soon as I plug the fiber in. I assume there could be an STP difference between the router module and the l2 switch fabric.

I'll let you know how it goes.

N8
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20 years 5 months ago #4307 by n8
After manipulating spantree settings on the switch I was able to drop the port recovery time down to 15 seconds from 40. Now I just need to figure out a way to get it to 1-2 seconds and I'm set.

Thanks for the help guys.

N8
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