Equipment Supporting 2.5gbps and 5gbps

Matthew Newton mcn4 at leicester.ac.uk
Thu Jan 28 16:42:43 UTC 2016


Hi,

On Thu, Jan 28, 2016 at 04:52:59PM +0100, Baldur Norddahl wrote:
> The standard 24 or 48 port SFP+ switch is 10 times the price of the
> equivalent switch with 24 or 48 port SFP. The same is true for the optics.
> 
> 2.5 and 4 Gbit/s SFP modules are available and cheap. It is just that
> ethernet ports will not take advantage of the extra speed. So it is only
> useful on fibrechannel ports.
> 
> It would be an improvement if we can get 2.5 or 4 Gbit/s ethernet on SFP
> instead of paying for an all SFP+ switch.

The issue that causes the need for 2.5 and 4Gbps is older cable
(cat5) that can't do anything faster, not the switches. You still
need to replace the switches to use the faster speeds.

This isn't the same issue with fibre, which can already support
10Gbps+. So it's the same difference. Upgrade switch on copper to
go from 1 to 2.5/4 Gbps; upgrade switch on fibre to go from 1 to
10Gbps.

The only possibility is if you got a 2.5/4Gbps SFP that would work
in a current generation switch. I very much doubt that's going to
work (but happy to be proven wrong by those in the know).

In my experience 10Gbps switches now cost about the same as 1Gbps
switches did a few years ago, so it's only the optics that are
pricey. Unless you get them from one of the many cheap suppliers
around, in which case there's essentially no difference in cost.

Cheers,

Matthew


-- 
Matthew Newton, Ph.D. <mcn4 at le.ac.uk>

Systems Specialist, Infrastructure Services,
I.T. Services, University of Leicester, Leicester LE1 7RH, United Kingdom

For IT help contact helpdesk extn. 2253, <ithelp at le.ac.uk>



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