This article describes a specific issue where a VC split causing connectivity issues after a Junos upgrade
When a 100G transceiver is a fiber cable, then the port won't come up and when a 100G transceiver is DAC, then the port will come up as 40G instead of 100G.
root@sw> show virtual-chassis vc-portlocalre:--------------------------------------------------------------------------Interface Type Trunk Status Speed Neighboror ID (mbps) ID InterfacePIC / Port0/54 Configured -1 Down 400000/55 Configured -1 Down 40000
Upon further research we found a PR matching this particular event:
Affected platforms:
QFX5120-48T:QFX5120-32C:QFX5120-48Y:QFX5110-48S:EX4650:EX4650-48Y-VC
> The issue experienced is resolved in the following Junos releases:
junos:22.1R3-S5 junos:22.2R3-S1 junos:22.2R3-S3 junos:22.3R2-S1 junos:22.3R3 junos:22.3R3-S2 junos:22.4R2 junos:22.4R3 junos:23.1R2 junos:23.2R1 junos:23.2R2 junos:23.3R1 junos:23.3R2