A UCS 6332 fabric interconnect has only 40G QSFP+ ports, but the upstream switches are 10G. How can the FI be uplinked at 10G, and why does the breakout option not appear on some ports?
With auto-negotiation off and 10G configured on sfp1/sfp2 of a CCR1036-12G-4S (RouterOS 6.43.8), MikroTik S+DA0001 and Amphenol DACs still run at 1G and the Cisco side shows no link at 10G. Which part of this link should be checked first?
Cisco troubleshooting document: inserting certain SFPs (for example GLC-SX-MMD or third-party modules) into a Catalyst 3850 C3850-NM sub-module produces %PLATFORMPM-6-MODULEERRDISABLE: The inserted SFP module ... is not supported and %PM-4-ERRDISABLE: gbic-invalid ... putting ... in err-disable…
The poster asked how to test fibre cables from a switch. The guidance covers reading optical levels with show interfaces transceiver / show controllers, comparing TX and RX at both ends, and recognising that a reading of -40, -50 or -80 dBm means no signal is being received. Hardware involved…
The poster could not find documentation for the command service unsupported-transceiver and asked what it does and whether there are consequences. It is one of Cisco's hidden commands: without it IOS disables a port when a non-Cisco transceiver is inserted, because the OS reads the vendor field and…
Discussion of why re-coded modules fail Cisco validation: Cisco SFPs carry a unique signature tied to each serial number in bytes 96-127, and editing vendor name or serial makes the signature no longer match, so the switch rejects the module unless the signature is regenerated. Hardware involved…
Dell R740xd servers with OEM Intel X710 adapters were cabled to Cisco switches with SFP-H10GB-CU5M and SFP-H10GB-CU3M DACs. Two cables linked, five did not; the working ones carried a blank or V02 version ID (made 2013), the failing ones V03 (made 2019), all identified as SFP-10GBase-CX1 on the…
Between VxRail Dell S5212F-ON TOR switches and Cisco C9500-48Y4C switches, FS.com SFP28 DACs behaved inconsistently: a 5 m cable custom-coded Cisco on one end and Dell on the other came Line Up, Protocol down; a 2 m Cisco/Cisco-coded cable linked; a 3 m cable would not link even with the 2 m…
A MikroTik CSS610-8P-2S+ (SwOS Lite) needed to connect its SFP+ ports to a Cisco Nexus 5596UP. The ports showed the transceivers in the web UI but no link, after trying several fibre cables and transceivers. The switch web UI listed vendor and type for each module, yet the port stayed at no-link…
A site decommission left me with a drawer of pulled Cisco optics, a mix of GBICs, 1G SFPs and 10G SFP+, and I have to decide which of them go back into production and which go in the bin. The GBICs I have put aside for now, since nothing on the bench takes them, so everything below is about the SFP…
All 10G ports on a Netgear M5300-28G3 were used, so the poster asked whether a Cisco 3 m SFP+ DAC (H10GB-CU3M) or Finisar FTLX8571D3BCL 10G SR modules could be used in the switch's 1G SFP ports to add another 10G-capable device at reduced speed. Hardware involved: Netgear M5300-28G3, Cisco…
The poster bought a Cisco SFP-10G-SR on eBay (markings suggesting 2007 manufacture) and, warned about counterfeit Cisco optics with longevity and safety risks, asked how to tell whether it was genuine before deploying it. Hardware involved: Cisco SFP-10G-SR. Reported symptoms/messages: authenticity…
We run a pair of racks that hand off to a carrier-facing Cisco NCS, and one of the 100G server uplinks has never come up since the build. Same result after moving the server to another cabinet with a different patch panel, so I have stopped treating it as a one-off. Supermicro server…
New ESXi host going into a rack that hangs off a campus 3850. Management on copper came up without drama, the 10G uplinks did not: as soon as the server boots, the switch port drops into err-disable and the host sees nothing on that vmnic. Lenovo ThinkSystem SR650, 7X06CTO1WW, with an Emulex VFA5.2…
Running a CWDM ring at the access layer, Catalyst 3750 at aggregation. I got plain modules with no vendor encoding, case marking TTG965D1, 1470-1610 nm grid. The link comes up, traffic flows, but the switch treats them as SX modules: in both inventory and monitoring it shows SX instead of CWDM, so…
