[Pc_Support] Re: ABS 8-Port, 5-Port GbE Switch -- VSC7388, VSC7385 (Blog article)

[Bryan J. Smith]

Derek Konigsberg <octo at logicprobe.org> wrote:
> Actual file transfers are much worse than these benchmarks,
> probably due to plenty of other factors including the fact that
> I'm using default 1500byte MTUs on all the links.

Using a layer-3 switch with wire-speed forwarding of separate
subnets/VLANs would let you transparently use 9000 byte jumbo frames.
 Around 400Mbps "real-world performance" becomes possible with NFS
UDP then.

> However, most people often don't even fully utilize 100Mbit
> ethernet. (though I'll easily exceed the speed of 10Mbit ethernet)

And I've seen some trashy, 802.3x-less setups where GbE is _slower_
than 100Mbps.  ;->

At least you're using some quality (if 8 year old) hardware -- both
concentrator and NIC.  Without the SRAM size on the GA620, you'd
probably run into performance issues.

Derek Konigsberg <octo at logicprobe.org> wrote:
> Yes, they are only layer-2 managed, and older ones.  But, I only
> need layer-2 switches.  Also, they work just perfectly fine for
> most needs.  I do all my layer-3 stuff on other devices, and just
> run VLANs through the switches.

Not if you want wire-speed performance.  I like switches where I can
plug in a node and it is in one VLAN/segment if it uses 1500 byte
MTUs and another if it uses 9000 byte MTUs and the switch does direct
switching.

> I also tend to prefer managed switches whenever I have the option,
> so I can do things like VLANs.  (and manual port settings, SNMP
> stuff, etc.)

And that's why I use layer-3 switches, taken to another level with
wire-speed routing of VLANs/different MTUs.  I'll then downlink to a
GbE desktop switch for cost.


-- 
Bryan J. Smith     Professional, Technical Annoyance
b.j.smith at ieee.org      http://thebs413.blogspot.com
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*** Speed doesn't kill, difference in speed does ***