Questions tagged “loopback”

4votes

1 answer

100views

ConnectX-4 MCX456A-ECAT will not link to a Cisco NCS on 100GBASE-LR4 while loopback passes on both ends

We run a pair of racks that hand off to a carrier-facing Cisco NCS, and one of the 100G server uplinks has never come up since the build. Same result after moving the server to another cabinet with a different patch panel, so I have stopped treating it as a one-off. Supermicro server…

txhub DE asked 1 month ago

3votes

1 answer

81views

Aruba 2530-48G pair over a new 200 m OM4 run: port 51 Down while the J4858C modules self-test fine

We had a 200 m OM4 backbone pulled between two buildings a while back and I am trying to light it with kit we already own. Both ends are 2530s, both modules are the HPE part, and the link simply will not come up. 2x Aruba 2530-48G 2x J4858C 1000SX, port 51 on each side roughly 200 m of freshly…

aruba aruba-2530 fiber-plant loopback SFP

rackhub KZ asked 1 month ago

2votes

1 answer

61views

Testing CWDM SFPs and CWDM-MUX-8A muxes back-to-back after links went err-disabled

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…

attenuator Cisco CWDM loopback Optical power

netrunner KR asked 2 months ago