Latest questions from the community.
We are refreshing the core of a small office and put in a pair of Aruba CX 6200F. The link between the two switches is meant to be a 10G trunk on the SFP+ uplinks, and I cannot get either box to admit that 10G exists on that port. 2x Aruba CX 6200F Switch Series, trunk on port 1/1/25 Cisco…
A good half of my work is putting one company's optics into another company's switch, so I spend a lot of time asking a module what it thinks it is. My toolbox for that is currently one command deep, and I would like to know what else is worth putting on the bench machine. Linux boxes with SFP+ and…
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…
We are pushing Wi-Fi into an outbuilding on a campus site. The only fibre going that way is a single strand, so the plan was to hang an AP-375 out there and feed it over a BiDi pair we already had on the shelf. Aruba AP-375, ArubaOS 8 Cisco BiDi SFP in the AP cage, its matching partner wavelength…
A dual-port ConnectX-5 (MT27800, firmware 16.35.1012, MLNXOFED 5.8 on BC-Linux 8.2) connected to a switch with a DAC would not recover after the cable had been connected and disconnected about fifteen times: the port stayed in State: Polling with Physical state ETHANFSMABILITYDETECT, and mlxlink…
On a Mellanox SN2410 (MLNX-OS 3.6.4112) a 100G port connected to a Chelsio adapter through a 2 m unequalised QSFP copper cable would not link when FEC was disabled; no HSS lane signal was detected on the adapter side. The poster required FEC-off operaation and asked whether the switch supports it…
I look after a two-building site and the access switches were replaced with Aruba 2540s a while back. The fibre between the buildings has not been touched, but since the swap the uplink refuses to come up. Aruba 2540 on our side, ports 51 and 52 used for the uplinks Aruba J4858D 1000SX in the 2540…
Mellanox-branded Q-4S28AO03 3 m QSFP28 AOC 1x4 breakout cables (100G with FEC) that worked under Onyx 3.9.1908 stopped linking after an upgrade to Onyx 3.10.x. The ports reported Cable speed not enabled and, with auto speed, Negotiation failure; supported speeds showed 1G/10G/25G but the actual…
A Synology RS3614xs+ with a supported Intel X520-DA2 rejected the wrongly ordered SFP+ modules as unsupported. Putting options ixgbe allowunsupportedsfp=1 into /etc/modules.conf had no effcet, and even when the kernel log showed ixgbe: allowunsupportedsfp Enabled the driver still reported failed to…
Adding a 100G link between two racks on an X690 that has been quietly doing 10G access work for a couple of years. The uplink cage will not take the speed at all. ExtremeSwitching X690-48x-2q-4c 1 m QSFP28 direct attach cable, Q28+CR41m port 57, one of the QSFP28 uplink cages The cable comes up as…
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…
A Mellanox ConnectX-4 Lx (MCX4121A-ACAAx, firmware 14.32.1900) in a Ryzen desktop (Fedora 41 and Windows 10) detected the interface but reported Cable is unplugged with two FS.com SFP28-25GLR-31 modules and a 40 m single-mode LC duplex patch; a MikroTik router recognised the same optics. The poster…
A Mellanox ConnectX-3 40GbE NIC connected with Mellanox QSFP passive copper cables (MC2210126-005) to a Dell PowerConnect 8164 (firmware 5.1.4.5) produced a link-up event for a few seconds followed by a permanent link-down. The same cables worked NIC-to-NIC, and Dell refused support because the…
We run a couple of IBM Power boxes next to a small SAN, and I am trying to write down a sane spares policy before the next hardware maintenance renewal. The part I cannot pin down is the transceiver itself: on some adapters it looks like a field-replaceable part in its own right, on others a…
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…
Standing up a small traffic-test bench next to the production fabric, and the tester ports will not come up over copper at all. HP 5900 40G switch, JC772A HP JG328A 40G QSFP+ direct attach cable Ixia Xcellon-Multis QSFP 40/10GE load module Spirent TestCenter 40G module, tried as a second opinion HP…
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…
Bench work: re-coding a small batch of SFP+ modules so they carry the vendor string and part number the customer's kit expects. The edit itself is trivial in a hex editor, the write goes through, the read back matches byte for byte what I wrote - and the host still throws the module out. generic…
Installing a new MES2324FB at a site to replace old hardware. The uplink is 1G fiber to an Alcatel 6224, Foxgate modules from the same batch as at neighboring sites. Setup: Eltex MES2324FB, firmware 4.0.4.7, also tried 4.0.6 - no difference 1G SFP Foxgate on both ends of the link far end - Alcatel…
I look after the access layer at a small ISP and I want our two GPON OLTs to show up in monitoring the same way everything else does. The wish list is not exotic: how hot the chassis runs, CPU and RAM load, counters per port, and the part I actually caare about, the optical side. That means Rx/Tx…
I look after a small office network and put in a DrayTek VigorSwitch FX2120 to get a 10G core. Both 10G links, to the router and to the NAS, came up on their own within seconds. What I cannot do is get a single 1G device onto the switch through the SFP+ cages. Switch: DrayTek VigorSwitch FX2120…
We are a small regional ISP rebuilding the optics budget for next year. Every 10G spare on our shelf is coded for exactly one platform, so the spares pool is roughly three times larger than our failure rate justifies. The idea on the table is to buy re-codable modules and code them ourselves as…
Replacing a customer's incumbent aggregation pair with CloudEngine kit, and the single link that refuses to come up is the 100GE feed into their packet broker. Everything else on the switch went in without drama. Huawei CloudEngine 6800, 100GE port 100GBASE-SR4 QSFP28 modules, Huawei parts, one at…
Commissioning a 10G handoff for a customer on a 3930 that was already on site. The module is Ciena's own, pulled from our stock, and the port does come up - but the operational state is UCTF instead of Ena and the uncertified transceiver alarm sits there permanently. The acceptance test includes a…
A Linux server with an Intel 82599ES 10-Gigabit SFI/SFP+ controller showed no 10G interface and dmesg contained failed to load because an unsupported SFP+ or QSFP module type was detected after an untested SFP+ module was inserted. The article explains that the ixgbe driver only enables modules it…
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…
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…
A Dell-branded Intel X520-DA2 with Flypro 10GBASE-T SFP+ modules showed no carrier (or no interface at all) on Debian and on FreeBSD-based OPNsense because the card rejects unapproved modules. The post collects the per-OS fixes and the permanent EEPROM approach. Hardware involved: Dell-branded…
Homelab switch: a D-Link DGS-1210-28 revision F1 that I flashed with OpenWrt so I could stop fighting the stock web UI. Everything works except the last four ports, which are the copper/fibre combo ones. Switch: D-Link DGS-1210-28 rev F1 Firmware: OpenWrt 21.02.0-rc3 (r16172-2aba3e9784) Ports…
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…
