SMC 8624T 24-port 10/100/1000 switch

Mark Hahn hahn at physics.mcmaster.ca
Tue Nov 12 11:34:09 EST 2002


> From what I can tell this is an unmanaged switch,
> that doesn't support port aggregation or
> mirroring, jumbo frames, etc?

does standard port aggregation work with the kernel?
would anyone care about managable switches in a cluster environment?
shame about jumbo frames, but doesn't the use of interrupt mitigation
by the kernel ameliorate that lack?

I suspect the lack of jumbo frames just reflects the size of 
buffers attached to each port.  I also guess that HP/d-link/smc/etc
are all using the same chipset, since they do seem to offer
pretty much exactly the same performance specs:

http://www.hp.com/rnd/products/switches/switch2708-2724/specs.htm

actually, the latency figures are interesting (and I don't remember
seeing them on the other specs).  I'm guessing there's a modular,
8pt chip that supports glueless connection to two peers.  the HP specs
show linear scaling for throughput, fabric speed and MAC table size;
it's sort of interesting that the max latency goes from 2.5 to 
12us in the 3-way config.  I expect that means that the throughput
rating only holds if you don't cross chip boundaries as well...

the dlink sheet says "8 Mbits of buffer per device" - I wonder 
if that's per 8-port chip?  the SMC datasheet is almost identical
except that it says "2 Mb per system" (it's also managed, does 
link aggregation))

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