Popular discussions about programming, compatibility and testing of optical transceivers.
An HPE FlexFabric 5950 48SFP28 8QSFP28 (JH402A) always downgrades an HPE JH419A 100G QSFP28 LC SWDM4 transceiver to 40G and never brings it up at full speed. Why?
What do the port states in the switchshow output of a Brocade Fibre Channel director or switch mean, and which of them point at the transceiver rather than the fabric?
An M290 with the optional two-port fibre module was fitted; can ports A0 and A1 be used as ordinary interfaces, for example for an ISP fibre handoff, and can a 1 Gb SFP be used in them?
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?
A 1000BASE-T copper SFP (Arista SFP-1G-T) in an Arista switch does not link to a device that only rnus 100 Mbit/s, and a 10GBASE-T SFP+ does not fall back to a lower rate either. How does EOS handle speed negotiation for copper SFP modules?
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…
Home rack, and the RB5009 has exactly one SFP+ cage. I wanted a second copper gigabit uplink out of it rather than pulling fibre across the room, so a copper module went in instead. MikroTik RB5009UG+S+IN, RouterOS 7.1rc4 MikroTik S-RJ01 1000BASE-T copper SFP in sfp-sfpplus1 Cat6 patch, about three…
Small vSphere cluster, two 10G uplinks per host into a pair of top-of-rack switches. After the ToR was rebooted for a firmware update, part of the VMs on one host went silent and vMotion failed on both uplinks - yet ESXi never marked anything down and the adapter LEDs stayed lit the whole time…
A customer with a 10Gtek ASF-10G-T 10GBASE-T transceiver could not read its EEPROM: ethtool -m ens802f0 returned Cannot get module EEPROM information: Operation not supported. The vendor attributed it to a firmware version mismatch between the NIC and the transceiver. Hardware involved: 10G NIC…
We are standing up four DGX Spark nodes for disttributed training and hung them off a MikroTik CRS812-8DS-2DQ-2DDQ. The plan was one 400G QSFP-DD port on the switch feeding two nodes at 200G each, so a couple of breakout cables cover the whole cluster. MikroTik CRS812-8DS-2DQ-2DDQ, QSFP-DD ports…
Huawei switches with third-party optics log SRM/3/SFPEXCEPTION ... Optical module exception, SFP is not certified daily, cluttering the logs during migrations even though the modules work. The modules pass traffic normlaly, but the daily SFPEXCEPTION traps flood the log buffer and the syslog…
We look after the switch management firmware on our own hardware, and ever since the SP/FPGA interface was changed from memory mapped buffers to a FIFO, the transceiver inventory has been coming back as junk on some ports. QSFP28 optics, all of them AFBR-89BDDZ out of the same batch reads go over…
I am putting together a switchless Fibre Channel setup at home: one box holds the storage and has to act as the FC target, the other two are plain initiaators. No FC switch in the middle, just direct cables between HBAs. Hardware: QLogic QLE2694 in the storage box, the one that should be the target…
We push traffic from a lab server into a CRS518-16XS-2XQ over a 100G QSFP28 uplink, and it leaves the switch through a MikroTik S+RJ10 copper SFP+ into a plain 1G RJ45 host. The receiving side is missing a large share of the packets and I cannot pin it on anything obvious. Setup: MikroTik…
On a Banana Pi BPI-R4 running OpenWRT 24.10.0 an SFP module failed with kernel logs failed to read EEPROM: -ENXIO and warnings that the module was slow to respond. The internet still worked but the log filled with the error, and the poster was unsure whether it pointed to a faulty stick, a GPON…
We run a pair of FortiGate 101F units for a 40-person office, nothing exotic. port17 carries an SFP uplink to the core switch, port19 is an RJ45 run to the server room, both of them inside the shared RJ45/SFP block (ports 17-20). In the maintenance window last month we took the pair up to FortiOS…
Adapter boards that, with a serial programmer, read and write transceiver memory across SFP, SFP+, SFP28, SFP112, QSFP/QSFP+/QSFP28, SFP-DD, QSFP-DD, XFP and OSFP. The software covers the MSA/CMIS memory maps, manages host/manufacturer passwords including brute-force search, changes…
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…
A pre-built HL15 server (Supermicro X11SPH-nCTPF wth Intel X722 SFP+ ports, Rocky Linux) would not link to a UniFi USW-24-POE over a VANDESAIL SFP+ DAC: the switch port stayed Disconnected under every negotiation setting on both sides. After ordering a 10Gtek cable the host reported network driver…
We are collapsing two aggregation rows onto FortiSwitch, and the last piece is a 25G interconnect between an FS2048 and an FS648 in adjacent racks. Everything else in the design came up on the first attempt; this one link refuses to. FortiSwitch 2048, 25G front-panel port FortiSwitch 648, 25G…
At home I've got Rostelecom fiber with the carrier's ONT installed, and I'd like to get the extra box out of the cabinet: plug an SFP ONU straight into the router and distribute it myself from there. I bought the stick, but I can't get past the first step. Keenetic Giga router, SFP port free Eltex…
Replacing an old Dell switch with an Extreme 5420M-24, the same SFP module that had worked in the Dell would not bring the network up: the uplink port was active with rising TX counters but RX stayed at zero, no DHCP address, no ping to the firewall, and a new SFP+ module behaved the same. Ethernet…
I run a small ISP's network and regularly reflash cheap modules for HP. Usual task: flash the vendor module's image into cheap Chinese 1.25G WDM modules so the switch accepts them without complaint. Donor is a J4859C, target hardware is an HP 2530-24G J9776A. What's on the bench: HP 2530-24G J9776A…
Small office, we are dropping the ISP-supplied box and terminating the fibre straight on the router. The handoff is AON, the provider only asks for a VLAN tag, no PPPoE and no ONT registration. What is in the rack: TP-Link ER7412-M2 V1, firmware 1.0.1, fibre into port 11 (SFP WAN) a TP-Link…
A web-based (Web Bluetooth) GUI for the UniFi SFP-Wizard device that reads SFP EEPROM, saves backups as .uieeprom files and writes from a prior backup. Limitations: the API does not flash directly; the dump goes to the device snapshot buffer for manual confirmation on the hardware; newer firmware…
Bringing up a 10G uplink from a PA-3220 to a new core switch. The module went into a free cage on the firewall, the switch side is configured and waiting, and the interface simply refuses to come up. The port LED blinks, which is what made me assume the module was at least being powered. Palo Alto…
A D-Link DES-3200-28 B1 switch logged DDM Port X optic module RX power exceeded the low warning/alarm threshold; the optical level looked abnormally low in the switch although the module measured fine when tested standalone. Hardware involved: D-Link DES-3200-28 B1, DDM-capable SFP. Reported…
Bought a StarTech ST10GSPEXNB to give a backup server a 10G SFP+ port, on the assumption that a card sold with a Linux driver would build against a current distribution. That was optimistic of me. StarTech ST10GSPEXNB, Tehuti TN4010 chip Debian 11, kernel 5.10.0-13-amd64, matching headers installed…
Putting a fibre run between two comms rooms in the same building and using a pair of TRENDnet TFC-1000MSC converters (1000BASE-T to 1000BASE-SX) to bridge it. Copper side goes straight into the switches we already have, nothing unusual in the config. TRENDnet TFC-1000MSC at each end, each on its…
