Hi, On Sun, Jan 27, 2013 at 11:04:28PM +0000, Nick Hilliard wrote: > On 25/01/2013 19:45, Gert Doering wrote: > > Which is not god-given but a design decision by certain BUs that *should* > > be able to get a faster CPU than a Z80 these days... > > but where do you want to stop? 128 vlans means 128 customers with a single > vlan each. What happens when you want 2000 customers or 4094 customers? > If you have a switch accepting hellos every 2 seconds per vlan and then > running the spanning tree calculation for each of these every time a > designated link flaps, you'll trash any cpu. The protocol itself doesn't > scale - it's great for small networks but it cannot scale beyond relatively > small installations.
Oh, please. Cisco can do it amazingly well on a 6500, which really does
not have that much of a CPU. It's a matter of having sane algorithms (STP
itself is not *that* complex to get right), a reasonable scheduler, and
a bit of beef in the CPU.
The pure number of VLANs is not the real deciding factor either - having
1000 VLANs on a single port each is less burden than 100 VLANs, but all
of them on 50 trunk ports. (I could see a router vendor having a limit
there, like "your number of active STP port-vlans must not exceed 100.000"
or such, but "128 vlan limit" is just silly^W product marketing)
gert
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Gert Doering - Munich, Germany [email protected]
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