QSFP: Difference between revisions
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In the world of network switching hardware (and to a lesser degree host [[NIC]]s), | |||
SFP, QSFP and acronyms like it describe a kind of physical slot that leaves the lowerst level of the [[network stack]], | |||
the PHY translation, up to the thing that slots in. | |||
The switch-transciever connection is OSI layer 1 - they move data, they are protocol-agnostic (they don't inspect it, they just move it). | |||
The switch-transciever connection is OSI layer 1 - they move data, they are protocol-agnostic (they don't inspect it). | |||
This means that with the right transceiver, it supports | This means that with the right transceiver, it supports | ||
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'''A little more practically''' | |||
In hosts there is not a lot of difference between a SFP card plus specific PHY, and a card that happens to have that PHY on its board, | |||
but in network switching hardware, the added flexibility (at only some extra cost) can save so much headache. | |||
In a lot of uses you'll see it just means "switch with a lot of 1gbit or 10gbit ports, with one or two SFP style slots that leave it open how you connect that to the rest of your infrastructure", then not unusually: | |||
10GBASE-X: offers choice between long distance and cheap at short run, | 10GBASE-X: offers choice between long distance and cheap at short run, | ||
CX4: Copper (4 parallel paths), ~15m over infiniband-style cable -- and a lot cheaper than LX4 | 10GBASE-CX4: Copper (4 parallel paths), ~15m over infiniband-style cable -- and a lot cheaper than LX4 | ||
LX4: Optical (4 wavelengths of light), depending on optics ~300m or 10km | 10GBASE-LX4: Optical (4 wavelengths of light), depending on optics ~300m or 10km | ||
...but will probably be replaced by 10GBASE-LRM for long distance optical, and 10BASE-T (Cat & RJ) for short runs. | ...but will probably be replaced by 10GBASE-LRM for long distance optical, and 10BASE-T (Cat & RJ) for short runs. | ||
40 gbit variant where you need that speed | |||
Only in a limited number of cases would you want to opt for a switch that consists of ''primarily'' unpopulated SFP style slots. | |||
QSFP is also hot-swappable (at physical layer, not all ''uses'' will be equally happy with you doing that). | |||
On the hardware side | |||
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* QSFP+ | * QSFP+ | ||
** | ** Typically 40Gbit max, mainly aimed at four 10 Gbit/s channels, 10GFC FiberChannel, or QDR InfiniBand, sometimes a single 40GBit Ethernet link | ||
* QSFP14 | |||
:: 50 Gbit/s, aimed at FDR InfiniBand, SAS-3, 16G Fibre Channel | |||
* QSFP28 | |||
:: 100 Gbit/s, aimed at 100 Gigabit Ethernet, EDR InfiniBand, 32G Fibre Channel | |||
* QSFP56 | |||
:: 200 Gbit/s, aimed at 200 Gigabit Ethernet, HDR InfiniBand, or 64G Fibre Channel | |||
Revision as of 14:16, 16 October 2023
✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.