I’m configuring a QSFP28 on a CRS510, and the config is as follows:
set [ find default-name=qsfp28-1-1 ] fec-mode=fec91 l2mtu=9014 mtu=9000
set [ find default-name=qsfp28-1-2 ] fec-mode=fec91 l2mtu=9014 mtu=9000
set [ find default-name=qsfp28-1-3 ] fec-mode=fec91 l2mtu=9014 mtu=9000
set [ find default-name=qsfp28-1-4 ] fec-mode=fec91 l2mtu=9014 mtu=9000
If I disable any of those four interfaces, the link goes down.
Why are there four layer 2 interfaces defined? It should be one interface (qsfp28-1) with four lanes when you monitor the optical stats.