https://nextheader.net/2014/10/31/snmp-stats-for-vcp-ports-in-virtual-chassis-fabricvcf/
Starting with 14.1X53-D10, the SNMP stats for VCP ports in Juniper VCF are available.
You will be able to retrieve the packet rate, bytes rate per second, the total number of bytes and packets per port per direction(in/out) among others.
To retrieve the stats, the following MIB object has to be used: jnxVirtualChassisPortEntry.
To activate the stats, a CLI command has to be configured under virtual-chassis hierarchy.
The command is:
set virtual-chassis vcp-snmp-statistics
{master:1} lab@QFX5100-5> show snmp mib walk ascii jnxVirtualChassisPortInOctets jnxVirtualChassisPortInOctets.0."vcp-255/0/48" = 56185113360 jnxVirtualChassisPortInOctets.0."vcp-255/0/49" = 35950458742 jnxVirtualChassisPortInOctets.1."vcp-255/0/48" = 21585094737 jnxVirtualChassisPortInOctets.1."vcp-255/0/49" = 39111551832 jnxVirtualChassisPortInOctets.2."vcp-255/0/48" = 39299502332 jnxVirtualChassisPortInOctets.2."vcp-255/0/49" = 36116503495 jnxVirtualChassisPortInOctets.3."vcp-255/0/48" = 21351278831 jnxVirtualChassisPortInOctets.3."vcp-255/0/49" = 55957682821
{master:1}
lab@QFX5100-5>