Programmers, coding boards, switches, NICs and other hardware
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…
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…
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 that 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 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, 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…
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 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…
Two Cisco Catalyst C1200-48T-4X switches were connected back-to-back with Cisco SFP-10G-LR modules in the ge49/te1 SFP+ slots. Both switches recognize the transceivers, the interfaces are administratively up, both ends transmit light and the DOM optical values are good, yet no link is established…