By default 2 QSPF+ ports on the rear are configured for VCP. Can we use 10G SFP+ to build Virtual chasis for longer distance on QSFP+ ports ? For example, in Brocade , we can use QSPF+ ports with 10GSFP+ to build chassis , the trade off is speed.
We have three EX4300-32F which are 80 meter apart, these switches have no uplink module ( 10GSFP+) but do have built in QSFP+ ports .
No, the rear QSFP+ ports are not able to be channelized into 4x10Gb ports. 40Gb SR4 does 100m on OM3 and 40Gb LR4 does 10km on SM so I'm not sure why you're concerned about 80m distance between switches.
On top of smickers input; You can create virtual chassis based on SFP+ ports - but with one contrain: You cannot use the 4 built-in SFP+ ports on EX4300-32F. It has to be via an uplink-module (EX-UM-4X4SFP for the EX4300-24T/EX4300-48T or EX-UM-8x8SFP for EX4300-32F)