Latest questions from the community.
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 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 whether 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-party 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…
While building a trunk between a Cisco Catalyst 3650-48PS and a Catalyst 3560CX-12PC using Cisco GLC-T copper SFPs at both ends, the 3560CX logged '%PHY-4-SFPNOTSUPPORTED: The SFP in Gi0/11 is not supported' and the link would not come up. The poster had already tried 'no errdisable detect cause…
The poster has a stack of two Cisco Catalyst 3850-48T switches, each fitted with a 2x1G/2x10G fiber uplink network module. Two 10G fiber links already run in slots 2/1/3 and 2/1/4. When a single-mode 1G SFP is inserted into 1G slot 2/1/1, the switch reports the module as unsupported and places the…
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…
The poster set up several new Cisco Catalyst 9300 switches fitted with C9300-NM-4G network modules, configured GigabitEthernet1/1/1 as a trunk and enabled it, but could not get a link with any of several SFPs. 'show interfaces' reports 'GigabitEthernet1/1/1 is down, line protocol is down…