Re: mac-address ageing per vlan

This might help.

http://books.google.com/books?id=eskSfkT3QMkC&pg=PA41&lpg=PA41&dq=accelerated+aging+forward-time&source=bl&ots=QZgqUkVCQc&sig=tNQOBdhMfuJKJwql_DCoKlLJBgs&hl=en&ei=jOD-Sun0AYe0tgez5Y2SDg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAgQ6AEwAA#v=onepage&q=accelerated%20aging%20forward-time&f=false

On Sat, Nov 14, 2009 at 11:50 AM, Abraham, Tharak
<tharakabraham_at_gmail.com> wrote:
> 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
>> > >
>> > >
>> > > Blogs and organic groups at http://www.ccie.net
>> > >
>> > >
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>> >
>> >
>> >
>> >
>> >
>> >
>>
>>
>> --
>> Andrew Lee Lissitz
>> all.from.nj_at_gmail.com
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
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Received on Sat Nov 14 2009 - 11:56:20 ART