====== SFP module (Small Form-factor Pluggable) ======

SFP modules followed on from [[rb:gbic|GBIC]] modules and are used in both ethernet and fibre channel switches (and others too), they are usually optical I/O modules although RJ45 copper Ethernet ones are available. Ethernet modules are most commonly 1GB/s but 10GB/s and higher are available. 

SFP used for Fibre channel can be 1 or 2GB/s but most common is 4GB/s.


===== LC Fibre =====


{{:rb:sfp1.jpg?200|}}
{{:rb:sfp2.jpg?200|}}
{{:rb:sfp3.jpg?200|}}

All the optical interfaces are either single or multimode fibre terminated on LC connectors.

{{:rb:sfp-plug.gif?200|}}


===== RJ45 =====


Although less common, SFP modules can have an RJ45 socket for copper connectivity.

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{{:rb:20180117_193033.jpg?200|}}


===== WDM Fibre =====

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{{rb:img_20250129_181046.jpg?170 |}}
Another option is Wavelength Division Multiplex SFP which use two different wavelength for Tx and Rx, so only needing one fibre. This example uses SC single mode ( SC == Stick 'n' Click )


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{{ :rb:single-bidirectional-fibre.jpg?400 |}}
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As this used two wavelengths, the SFP needs an optical splitter, and will have both a laser and receiver on the two prism ports.

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{{:rb:img_20250129_181211.jpg?200 |}}
I'm guessing here, but I believe the laser is mounted at the rear with the 3 pins connection to the PCB, and the RX connections are on the side with flexible connection to the PCB.
{{ rb:img_20250129_181824.jpg?200|}}

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{{:rb:img_20250129_181655.jpg?200 |}}
Close-up of the Prism housing and SC receptacle.



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===== Multimode Fibre =====

Just a look inside for interest...

{{:rb:sfp_152322.jpg?200 |}}


{{:rb:sfp_152240.jpg?200 |}}

My guess is that the Single mode SFP are very similar to the Multi Mode, although the lasers may be more powerful, possibly bigger or have a heatsink?

===== SFP commands - IOS =====

Specific to Cisco IOS as SFPs can be found in Fibre Channel SAN switches and other manufacturer's kit.


Inserting a SFP module
<code>
router01#
*Nov 30 19:44:22.751: %EHWIC_1GE_SFP_CU-6-SFP_INSERTED: Transceiver module 1000BaseSX SFP is inserted in GigabitEthernet0/0/0 interface.
</code>

This is in a [[networking:cisco-1921|Cisco 1921 Gigabit router]] with a WIC for gigabit copper and and SFP module.
<code>
router01#sh inventory 
NAME: "CISCO1921/K9", DESCR: "CISCO1921/K9 chassis, Hw Serial#: FCZ1625C5YF, Hw Revision: 1.0"
PID: CISCO1921/K9      , VID: V04 , SN: FCZ1625C5YF

NAME: "Enhanced High Speed WAN Interface Card-1 Port Gigabit Ethernet SFP/Cu on Slot 0 SubSlot 0", DESCR: "Enhanced High Speed WAN Interfa"
PID: EHWIC-1GE-SFP-CU  , VID: V01, SN: FOC15164VRP

NAME: "1000BASE-SX SFP", DESCR: "1000BASE-SX SFP"
PID:  , VID:    , SN: FNS1007Q4PF

</code>