Written by James McDonald

July 4, 2023

I have 3 Cisco ws-c2960x-24pd-l switches on a site with SFP+ slots (10GB)

The switches were relocated when the business moved to another factory. The old factory must of had single-mode fibre links because the switches had SFP-10G-LR-S SFP+’s which are single-mode transcievers.

The IT company relocated the switches installed and patched them into the new factory cabinets using a mix of single-mode and multi-mode patch leads.

What SR and LR means

SR = Short Read = Multimode Fibre
LR = Long Read = Singlemode Fibre

Who I got to do a cable audit

I got https://www.connexsolutions.com.au/ to inspect the cabinet to cabinet cabling and found OM1 and OM3 links. OM1 doesn’t support 10GB so I had to get a mix of 1GB and 10GB SFP’s. Both OM1 and OM3 are multi-mode fibres.

Who I bought replacement SFP’s and patch leads from

I ended up buying Cisco compatible Plusoptic SFP’s from 4 Cabling https://www.4cabling.com.au/

Cisco compatible (SFP-10G-SR SFP-10G-SR-X SFP-10G-SR-S) 10G, SFP+, 850nm, 300M Transceiver, LC Connector for MMF with DOM. SFP-10G-SR-CIS – Single UnitSFP-10G-SR-CISA$75.002A$150.00
Cisco compatible (GLC-SX-MM GLC-SX-MMD ONS-SC-GE-SX SFP-GE-S) 1.25G, SFP, 850nm, 300M Transceiver, LC Connector for MMF with DOM. SFP-1G-SX3-CIS – Single UnitSFP-1G-SX3-CISA$45.002A$90.00

I haven’t done many SFP swaps

I had to power cycle all the switches to get them to recognize the SFP’s these take about 6 – 10 minutes to fully power up.

How to Identify SFP’s

Cisco command to show installed SFP’s is show inventory


NAME: "1", DESCR: "WS-C2960X-24PD-L"
NAME: "TenGigabitEthernet1/0/1", DESCR: "SFP-10GBase-LR"
PID: SFP-10G-LR-S        , VID: V01  , SN: FNS22090L47
NAME: "TenGigabitEthernet1/0/2", DESCR: "SFP-10GBase-LR"
PID: SFP-10G-LR-S        , VID: V01  , SN: FNS22090L4V


NAME: "1", DESCR: "WS-C2960X-24PD-L"
NAME: "GigabitEthernet1/0/25", DESCR: "1000BaseSX SFP"
PID: GLC-SX-MMD , VID: V01 , SN: PC23020839
NAME: "TenGigabitEthernet1/0/2", DESCR: "SFP-10GBase-SR"
PID: SFP-10G-SR , VID: V03 , SN: E230529031


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