Re: mac-address ageing per vlan

Thanks Johny !
That answered my question directly but i had a confusion with accelerated
aging/forward delay config.and thats why this thread popped up.

Andrew,
Is it 15 secs that the "short aging" time the Doc refers to in the case of
pvst+ ?
Better to test it though, i can do it tomorrow.

Thanks again guys !

Tharak Abraham.

On Sat, Nov 14, 2009 at 6:57 PM, ALL From_NJ <all.from.nj_at_gmail.com> wrote:

> I have always found this to be an interesting topic ... mainly, because it
> occurs automatically and we do not think much of it (except for CCIE
> studies!)
>
> Here is the link I assume you are referring to?
>
> http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_25_se/configuration/guide/swstp.html#wp1169222
>
>
> Johnny mentioned the command to set the aging time manually. I think he
> answers your question.
>
> - Team - keep me honest here ...
>
> A couple of thoughts around this and to try and keep things clear (at least
> in my head).
>
> W/ rapid spt the mac address is immediately deleted when a TCN is learned,
> no need to rely on the aging timers per mac address. MSTP is built on
> rapid
> stp, so it also performs the same.
>
> When spt needs to converge different paths may exist throughout. What
> would
> happen if all the mac addresses are learned over an interface that is no
> longer the forwarding one? Some confusion within the switch perhaps;
> especially when it starts to learn mac addresses over different interfaces.
>
>
> So the switch should age these mac addresses per the forwarding time, and
> as
> the documentation mentions. This makes sense for STP.
>
> Does the forwarding time have affect with rapid and or mstp for alternate
> links? Humm ... not really. What does this mean for the aging times? My
> understanding is that these are aged out immediately for the vlans that
> were
> affected.
>
> Anyone see this in the docs or a lab test? I would lab test it but I have
> no time today till maybe late tonight.
>
> Can you believe I am still working on leaves and honey-do lists? Ok,
> honey-do lists of course ... these never end, but still raking leaves?
> Sadly true ...
>
> I feel like Fred Sanford from 'Sanford and son' crying about my back and
> heart ... no one seems to care. ;-) ... crickets and tumbleweeds are all
> I
> hear and see when I say these things ... oh humm ... it is hard to be me.
> lol
>
> Andrew Lee Lissitz
>
>
>
>
> On Sat, Nov 14, 2009 at 1:11 AM, Johnny B CCIE <jbccie_at_gmail.com> wrote:
>
> > conf t
> > mac address-table aging-time x vlan xx
> >
> > The default value x is 300 seconds = 5minutes.
> > If you use x = 0, then you have disabled aging for the vlan in question.
> >
> >
> >
> > On Sat, Nov 14, 2009 at 12:42 AM, Abraham, Tharak
> > <tharakabraham_at_gmail.com> wrote:
> > > Gents,
> > >
> > > Could you explain how to enable mac-add ageing for a particular vlan ?
> > >
> > > Just read that accelerated-ageing for a particular vlan can be linked
> > with
> > > STP for that vlan with the forward time.
> > > i.e spanning-tree vlan x forward-time y
> > >
> > > Could someone add more thoughts on this ?
> > >
> > > Tharak
> > >
> > >
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>
>
> --
> Andrew Lee Lissitz
> all.from.nj_at_gmail.com
>
>
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Received on Sat Nov 14 2009 - 22:20:59 ART