That isn't always true. Some switches are already speced as full. It's best to read the product docs or speak with a rep to be sure. tv ----- Original Message ----- From: "Eric Gearhart" <eric@nixwizard.net> To: "NANOG list" <nanog@nanog.org> Sent: Tuesday, February 24, 2009 9:51 AM Subject: Re: switch speed question
On Tue, Feb 24, 2009 at 2:33 AM, Bruce Grobler <bruce@yoafrica.com> wrote:
Hi,
It depends on how heavily loaded your switch is expected to be, for instance two machines using the switch will be able to get a full 1Gbps, however depending on the backplane (switching fabric), it limits how many ports will receive full 1Gbps when the switch is congested, e.g. a 2 gig backplane against a 24 gig.
Regards,
Bruce
Note that the traffic to a switch is bi-directional (full duplex) - so a 24 port gigabit switch can max out its 32 Gig backplane, if all 24 ports have a gig coming in and going out (24 X 2 is 48, more than the 32 gig backplane).
This isn't immediately apparent - the other day someone at my work asked the exact question "Why's the 32 gig backplane > the 24 ports on the switch?"
-- Eric http://nixwizard.net