From: Victor Cappuccio (vcappuccio@gmail.com)
Date: Tue Nov 06 2007 - 11:55:22 ART
to what Jose just mentioned, I would like to add that you can also play a
little bit with this commands in the Switch
Sw1#test spanning-tree diameter 2
diameter 2 and hello time 2 gives max age = 10 and forward delay 7
Sw1#test spanning-tree diameter 3
diameter 3 and hello time 2 gives max age = 12 and forward delay 9
Sw1#test spanning-tree diameter 4
diameter 4 and hello time 2 gives max age = 14 and forward delay 10
Sw1#test spanning-tree diameter 5
diameter 5 and hello time 2 gives max age = 16 and forward delay 12
Sw1#test spanning-tree diameter 6
diameter 6 and hello time 2 gives max age = 18 and forward delay 13
Sw1#test spanning-tree diameter 7
diameter 7 and hello time 2 gives max age = 20 and forward delay 15
Sw1#test spanning-tree diameter 7
diameter 7 and hello time 2 gives max age = 20 and forward delay 15
On Nov 6, 2007 3:35 PM, Joseph Brunner <joe@affirmedsystems.com> wrote:
> Actually I have seen diameters greater than 7 just recently (perhaps as
> much
> as 11).
>
> I believe the original standard was written at a time when they didn't
> have
> what we know as a switch (hubs, translational bridges, etc.)
>
> Its far better to layer 3 route as we all know, so why not just keep your
> diameter around 2 (access to distribution) then route after that?
>
> Layer 3 switches today can be had for dirt prices (ok, maybe dell/hp)...
>
> -Joe
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> sheherezada@gmail.com
> Sent: Tuesday, November 06, 2007 4:43 AM
> To: Cisco certification
> Subject: OT: STP diameter
>
> Hi,
>
> I suppose that daisy-chaining switches beyond 3 or 4 bridges is not
> recommended, because I have never saw this in a reference design. I
> also know the IEEE 802.1D recommendation of having no more than 7
> bridges diameter with the default STP timers. However, can anyone
> tell me WHY having a 7-8 bridge loop topology is such a bad idea in
> practice after all, especially with RSTP, apart from possibly
> degrading convergence time? I am not saying that this would be good,
> I just want to clear the FUD. My understanding is that the
> theoretical diameter is given by the Max Age value, hence we may have
> a maximum diameter of 20.
>
> Thanks,
>
> Mihai
>
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-- Victor Cappuccio www.vcappuccio.wordpress.com
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