Latest questions from the community.
The poster needed to connect a MikroTik CRS328-4C-20S-4S+RM to an HP 1820-24G-PoE+ over 200-500 m of outdoor aerial fibre and asked which SFP modules to buy and how to verify compatibility before purchase. The HP compatibility table listed only J4859C as a single-mode SFP, while MikroTik offered…
The postter had an existing multimode fibre run of about 200 m that could not be replaced and only single-moode SFP modules available. The question was whether a 1G single-mode SFP pair would establish a stable link over multimode fibre, and what the practical limits were. The thread also raised…
The poster wanted to verify whether an HPE StorageWorks 81B 8 Gb Fibre Channel HBA (AP769-60001) fitted with an AJ716B SFP could be used in an HPE ProLiant DL380 Gen10 server (P02464-B21) and asked for a tool where part numbers can be entered to get a compatibility verdict. No error had occurred…
The poster wanted a cheap 10G link between servers with Intel X520-DA2 NICs and an HP switch and worried that a direct-attach cable is coded either for Intel or for HP but not both. A respondent shared that two X520-DA2 cards would not link directly over a DAC in their case, but a Dell DAC…
The poster wanted to run 100 Mbps fibre SFP modules in a D-Link DES-3200-28F but the vendor compatibility list only named older switches (DES-1228, DES-1252, DGS-3612G). The question was whether the list was simply stale or whether the modules would be rejected by the newer switch. A related…
The poster owned a MikroTik RB962UiGS-5HacT2HnT (hAP ac) with a single SFP cage and had two spare 850 nm modules on hand: a Cisco-branded AFBR-57F5PZ-CS1 and an Intel-branded FTLX8571D3BCVIT1. The ISP delivered the service over a single fibre strand rather than a duplex pair, and the posster wanted…
The thread starter had a set of Cisco EEPROM images (SX, LH, ZX types) but no CWDM images and wanted CWDM SFP modules to show up on Cisco switches as CWDM/WDM optics rather than being misidentified as SX or LX. Without a correct image the switch either reported the module as unsupported or forced…
The thread starter wanted to reprogram GBIC and SFP module EEPROMs but found that guides were disappearing from forums. Questions covered which programmer to use, where to attach the I2C lines on the module, whether the module needs 5 V (GBIC) or 3.3 V (SFP), and how to treat the memory as a…
The poster planned a server with an Intel X710-DA2 dual-port SFP+ NIC connected to two Ubiquiti EdgeSwitch 48 Lite units, with LACP between the switches. Six 10G SFP+ modules were needed (two for the server side, four for the switches) and the question was which modules would be recognised by both…
The poster wanted to dump the EEPROM of a QSFP+ transceiver plugged into an Intel XL710-QDA1 and ideally read live DDM values such as received optical power, as they were used to doing with SFP modules on other adatpers. With i40e 2.0.23 and firmware 5.05 0x800028a2 1.1568.0, ethtool -m eth0…
A brand-new retail Intel E810-XXVDA2 on Windows Server 2022 (Intel driver 1.12.164.0 from release package 28) was connected to an SFP28 port of a Ubiquiti USW-Pro-Aggregation switch. With an SFP28 DAC the link came up at 25G immediately, but with SFP28 optical transceivers (Ubiquiti…
On Ubuntu 18.04 (kernel 5.4.0, ethtool 5.3, i40e 2.8.20-k) the poster used 25G XXV710-based NICs bought from FS.com (FS part XXV710AM2-F2, Intel XXV710 chipset). Link and error-free wire-speed traffic worked, but reading a transceiver's DMI data with sudo ethtool -m enp4s0f0 failed with "Cannot get…
The poster was building a server that needed a 1 Gbps single-mode fibre uplink and wanted a PCIe card with two to four SFP cages so any optic could be used later. The core doubt: switches usually accept plain 1G SFP optics in SFP+ ports, but is the same true for 10GbE server NICs, or would the NIC…
For a deployment on Dell PowerEdge R630 and C4140 servers the poster had Intel X520-SR2 adapters (E10G42BFSR) fitted with the bundled Intel FTLX8571D3BCV-I3 10GBASE-SR SFP+ modules (850 nm, 300 m multimode). The uplink switch is a Huawei Quidway 9300 whose SFP+ ports carry 10GBASE-LR (1310 nm)…
The poster spent a day and a half chasing an Intel 82599EB-based 10G SFP+ NIC that VMware ESXi 6 reported as down although the link LEDs were green on both ends of the fibre and the Cisco 8500 switch showed the port up/up. The cause turned out to be the Cisco SFP-10G-LRM module used throuhout their…
The poster's Cisco Catalyst C9500-48Y4C switches (IOS XE 16.12.04 after an upgrade) refuse to work with a batch of genuine Cisco SFP-10G-SR modules (VID V03, serials AVD2231D3TE and AVD2231D3RW): 'show inventory' lists them as 'GE ZX' instead of 'SFP+ 10GBASE-SR' and the ports stay non-functional…
The poster's Intel Ethernet Converged Network Adapter X710 would not come up with third-party Fiberxon 10G SFP+ modules: the i40e driver, version 1.2.48, refused to initialise and reported "The driver failed to load because unsupported module type was detected." They asked how to switch on an…
The poster, validating their product against Cisco Nexus 9000 switches (a Nexus C9332D-GX2B chassis), is blocked by bug CSCwo18785: configuring 200G on a QSFP-200G DAC fails with 'ERROR: The transceiver doesn't support this speed'. The cable is a Mellanox MCP1650-H002E26 200GbE DAC; connected…
The poster compiled and loaded i40e 3.4.2 on Ubuntu 16.04 for an Intel XL710-QDA2 dual-port 40GbE adapter. The driver loaded fine, but as soon as non-Intel QSFP+ cables were attached dmesg reported "Rx/Tx is disabled on this device because an unsupported SFP+ module type was detected." and no link…
The poster wanted to use a Finisar FCLF8521P2BTL 1000BASE-T copper SFP in an Intel X710-DA2 running NVM 7.1. Intel's X710/XXV710/XL710 Feature Support Matrix (rev. 3.4, Nov 2019, doc 332191-024) lists single-speed SFP 1GBASE-T transceivers with support limited to Finisar FCLF-8521-3, Kinnex A…
While rolling out single-mode fiber between Cisco CBS350-8MGP-2X switches (firmware 3.4.0.17) with SFP-10G-LR modules, the poster hit strange behaviour: the link only comes up if the duplex LC connector is split and the TX fiber is inserted first, then the RX fiber. Inserting the joined LC…
The poster connects a Cisco Catalyst C9300X-24Y to a FortiGate firewall with a 25G SFP-H25G-CU2M DAC. Whenever the DAC is inserted the switch logs '%PLATFORMPM-6-MODULEINSERTED: SFP module inserted with interface name Twe1/0/23' followed by '%PLATFORMPM-6-DIFFERENTMODULEINSERTED: Warning: SFP…
A Cisco Nexus 5672UP fitted with a 10GBASE-SR SFP+ could not connect to another switch that uses a 1000BASE-SX (1 Gbps) transceiver; both ends are multimode optics. When the poster changed the port speed, 'show interface brief' displayed an 'SFP checksum error', and swapping the Nexus optic for a 1…
The poster is searching for GPON or XGS-PON SFP ONT sticks with a built-in MAC that work in Cisco routers, since Cisco does not sell such modules. Previous attempts with third-party ONT sticks were largely unsuccessful even after enabling 'service unsupported-transceiver'. In a follow-up the poster…
Before replacing an old switch with a Cisco Catalyst 9300-M, the poster wanted to know whetther the existing SFP could be reused and posted the 'show idprom interface gigabitEthernet 1/1/1' output: Vendor Name CISCO-FINISAR, Vendor Part Number FTLF1318P2BCL-C3, serial FNS15510U5B, 1310 nm, single…
On an IOS XR router (RSP-based ASR 9000 class, observed on IOS XR 4.x and 5.x), the poster configured a tunable DWDM XFP with 'controller dwdm 0/1/0/0', 'admin-state maintenance', 'wavelength 55', 'admin-state in-service' and then brought the TenGigE interface up. The running configuration shows…
The poster's newly acquired Cisco Catalyst 9300 (with an 8-port 10G SFP+ network module) would not link to a Cisco Catalyst 4503-E tat only has 1G SFP ports. Suspecting a 10G-versus-1G speed mismatch, the poster tried to force the 9300's 10G SFP to operate at 1G with the 'speed' command, but the…
Two Cisco Nexus 93108TC-FX3P switches on NX-OS 9.3(11) are connected with genuine QSFP-100G-CU1M DACs but the link never comes up. The compatibility matrix says the cable is supported from NX-OS 9.3.5. The port config is a plain 'switchport mode trunk' / 'no shutdown', and 'show interface eth1/54…
The poster uses Ubiquiti (UBNT) SFP and SFP+ modules, both multimode and single-mode, in Cisco switches. They work perfectly in Catalyst 9300 and 3650 switches with current IOS, but in a Catalyst C1000 and a Catalyst 2960 the modules are detected on insertion yet reported as 'unknown' in 'show…
The poster asked whether anyone had used third-party optcis in a Cisco Catalyst 9300 series switch running IOS XE Everest (16.x), and specifically whether the hidden global command 'service unsupported-transceiver', long used on older Catalyst platforms to accept non-Cisco SFPs, still functions on…
The poster needs a 100GE link between a Cisco NCS55A2-MOD (NC55-MPA-4H-S MPA) and a Cisco Catalyst C9500-48Y4C using a QSFP-100G-CU1M DAC. Both platforms list the cable as supported, yet the link never comes up at the physical level. Because the Catalyst 9500 lacks 100G auto-negotiation (bug…
The poster was connecting a Cisco Nexus 93180YC-FX to an Arista 7050SX3 with a 25G AOC sold as Cisco/Arista compatible. The Nexus detects the transceiver, but 'show interface status' reports the port as not connected. A 10G AOC from the same vendor works fine between the two switches, and the same…
The poster wanted to run a link bidirectionally over one strand of single-mode fiber on a Cisco Small Business 300 series switch. Cisco's SMB catalogue lists the MFEBX1 100 Mb BiDi SFP (transmitting at 1310 nm and receiving at 1550 nm), but the poster could not find a Cisco part number for the…
The poster spent two days trying to bring up a single-mode fiber link between an older Arista switch and a Cisco Catalyst 3650 (IOS-XE 3.7.5) with Cisco GLC-LH-SMD (SFP-LH-SMD) optics; the path runs through five patch cords in the same building and had been tested by the cabling contractor. At…
The poster, a new owner of a Cisco Nexus 93180YC-EX running NX-OS 7.0(3)I4(7), cannot bring up any 25G link. ipolex SFP28 DAC cables are recognized ('type is SFP-H25GB-CU1M', 'name is OEM', 'part number is SFP-H25G-CU1M', 'nominal bitrate is 25500 MBit/sec', 'DOM is not supported') but the port…
The poster runs temporary event networks and has twice hit heavy frame errors on 10G links between MikroTik and Cisco switches. About a year earlier a Cisco Catalyst 2960-S with 10G uplinks connected to a MikroTik CRS317-1G-16S+ showed CRC errors on the Cisco side and swapping cables did not help…
On a Cisco Nexus N9K-C93180YC-FX, QSFP-40G-SR-BD BiDi modules are not detected at all: nothing appears in the logs when they are inserted and they are absent from 'show interface transceiver', whereas QSFP-40GE-LR4 modules in the same ports are logged and listed normally. Several QSFP-40G-SR-BD…
The poster asked whether a 10G SFP+ SR or LR optic in one switch can auto-negotiate down to 1G to link over fiber with a 1G SFP in another switch, and if not, how to attach a handful of 1G optical connections from a 1G switch to a 10G switch. They understood that Cisco SFP+ optics run only at 10G…
In the poster's data center several Cisco CWDM SFP/GBIC links stopped working: some ports went err-disabled (one with link-flap as the cause) and others simply showed notconnect. Troubleshooting included shut/no shut, reseating the modules, moving the CWDM SFPs to other ports, replacing the patch…
The poster wanted to use a 40G QSFP+ to 4x10G SFP+ DAC breakout cable on a Cisco Catalyst 9500-32QC-E running IOS XE 17.6.4 (Bengaluru). The 'hw-module breakout' command is rejected; in global configuration only 'hw-module slot' and 'hw-module subslot' are offered. The switch is not running…
The poster could not find Cisco documentation describing how to set the frequency or ITU channel of a DWDM-SFP10G-C tunable 10G SFP+. A follow-up question asked whether a CPAK-100G-LR4 in a CRS-X 4-port 100GE LAN/OTN card could be tuned to a wavelength and connected directly to a ROADM of an…
A Cisco Catalyst 3850-24XS with an SFP-10G-LR (1310 nm) connects over a single-mode cross-connect to a Tier-1 carrier's layer-2 DWDM equipment in the same data center. When the carrier shuts the circuit down, TenGigabitEthernet2/0/23 goes 'down, line protocol is down (notconnect)' yet 'show…
Two Cisco Catalyst 3750-X switches (WS-C3750X-24P-L and WS-C3750X-48P-L) run identical code. A Cisco GLC-SX-MMD is detected normlly in Gi1/1/1 of the first switch, but the second switch reports 'media type is Not Present' with 'link type is force-up' on Gi1/1/1, and 'show idprom interface Gi 1/1/1'…
The poster (in a machine-translated post from the Spanish-language community) tried to connect two Cisco Business CBS350-24T-4X switches through their SFP+ ports using MikroTik XS+2733LC15D modules. No connectivity is established and the ports end up blocked by the switch's Link Flap Prevention…
The psoter planned to install an Intel X520 adapter (Cisco PID N2XX-AIPCI01) into a Cisco UCS C240 server and use Cisco SFP-10G-SR or SFP-10G-LR transceivers, and asked whether the combination has compatibility problems. A later reader asked whether the Cisco SFP-H10GB-CU3M= twinax cable would work…
A friend of the poster bought several GLC-T copper SFPs sold as original Cisco, but their serial numbers had an unfamiliar format (00000MTC1719055H, 00000MTC171903XL and similar). 'show interface ethernet 1/45 transceiver sprom' on a Cisco Nexus 5596 lists the module as SFP-1000BASE-T, vendor name…
The poster connected a Dell server to a Cisco Catalyst C9500-48Y4C (IOS XE 17.9.3) using a Dell L56SF018-SD-R 3 m DAC (DAC-SFP-3M). The cable is not in Cisco's optics compatibility matrix, and 'show interface status' shows port TwentyFiveGigE1/0/35 as err-disabled. Logging shows…
The poster asked why third-party SFP modules stopped working after upgrading Cisco switches to IOS 15.2, whereas other vendors accept Cisco or other optics, and whhether this is a technical limitation. No model, log output or interface details were given despite requests. In a later update the…
The poster wanted to use third-paty SFP modules in a Cisco Catalyst 2960L-48TS (LAN Lite feature set, image c2960l-universalk9-mz.152-6.E2b). Entering 'service unsupported-transceiver' in global configuration mode only produced a command error because the CLI does not know the command on this…
The poster runs a Cisco Nexus 5000 with an N2K-C2232PP-10GE fabric extender. Three FEX-facing ports report 'sfp validation failed' with Cisco FET-10G modules. Following advice found online, the module was removed, the port speed set to 1000 and the module reinserted; the port was also shut/no shut…
