VSS Dual-Active concept doubt

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Jul 30th, 2013
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Hi All

My doubt is about the need of each switch connected to the VSS using L2 or L3 MEC to be ePagp trustable for Dual-Active Detection.

If just one or two of my switches are configured with ePagp and are trustable for Dual-Active Detection, is this enough to the entire VSS realize that it´s in Dual-Active condition and take the action required to stablish the whole enviroment (all switches) ?


Each switch must have a Dual-Active Detection mechanism in implemented on it, so it can keep working when Dual-Active condition ocour?

Can i use ePagp for some switches and BFD for others (3750 stack) ?


Rafael Giuri

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Reza Sharifi Tue, 07/30/2013 - 17:16
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You just need to enable ePAGP dual active detection on one portchannel that connects to one of your access switch..

dual-active detection pagp trust channel-group xx

Also, you usually run only one method for dual active detection and not ePAGP and BFD as the same time.

They are different, BFD is a direct connection between the 2 VSS switches, but ePAGP uses the access switch.


Simon Leigh Wed, 07/31/2013 - 02:58
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I would also recommend using fast hello as a back up detection for dual active detection.

You can use upto 4 Ethernet connections for this.

I use 2 copper ports in my VSS for this.

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