SFP ports and Giga ports

Unanswered Question
Oct 5th, 2009

Hi all,

I am designing a network where fiber will have a key role and I am wondering what is the max throughput of a SFP port (1000BaseSX), and why would I go for that kind of port rather than a normal Giga port...

I have been looking around for documents and papers but nothing so far.

Thanks to help

I have this problem too.
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viyuan700 Mon, 10/05/2009 - 04:37


SFP port (1000BaseSX) will not give you a better throughput BUT will certainly give you a better distance. Fiber media is to give you longer distance not possible with copper.

For better throughput i think you have to look for a switch which gives you better packet per second forwarding rate. Not able to get a document which list packet per second forwarding rate. You can ask in LAN area of the discussion.

Leo Laohoo Mon, 10/05/2009 - 13:48

Maximum throughput is based entirely on your appliance.

Switch Performance Portable Product Sheet


Router Performance Portable Product Sheet


Take note that the file is dated 2008 so I don't know how often Cisco updates these.

Hope this helps.

coletemple Tue, 10/06/2009 - 01:06

Thanks guys.

My customer has specified to have fibers between distribution and access switches, the access switch I have choosen is a catalyst 2960 which have trunk with distribution switch (SFP port). I have been obliged to put a 3750G-12S (12 SFP ports) to increase my SFP ports and connect all the switches together (see pict). But the budget for this design is expensive (fibers, transceivers, switches...) that's why I start wondering why not to use giga ports (even bundle them up...). I am still looking for a guidance here.

Tom Randstrom Tue, 10/06/2009 - 04:58

As has been stated, a copper GE port and a fiber GE port carry the same amount of data. The fiber solution will enable longer distances. Thus, most users use copper cables when the distances are shorter and save money on the optics, cabling and switches.

Your customer may be trying to future-proof his infrastructure by installing fiber, expecting to move to 10G, 40G or 100G in the future. Your customer might be able to build a more cost effective solution by installing both copper and fiber cabling today, but turn-up the network using only the copper cables today.

viyuan700 Tue, 10/06/2009 - 06:18

"why not to use giga ports (even bundle them up"

FOr access switches, 48 10/100 ports right now you have one Gig port uplink going to 2 different switch. You cannot bundle those 2 ports as they are going to different switches. If you are using 1 uplink for all the vlan then other is blocked by STP. What can be done is if you have more than 1 vlan on access switch you can use 1 uplink for some vlan and other for some vlan.

Your distribution switch with 12SFP port is using 8 ports as per your design, so you left with 4 SFP ports which you can use in future when your traffic grows. That time you can bundle the link which has 2 links between the same switches.


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