Hi,
On a EX2300 device, you cannot use 1G ports to form a Virtual Chassis. EX2300 switches do not have dedicated VCP ports and so you only have to use the 10G Uplink ports by converting them into VCP. Now these 10G uplink ports support SFP and SFP+ transceivers as well but only SFP+ transceivers are to be used for Virtual Chassis VCP ports.
However, on a EX2200 device, you can use 1Gig ports as VCP to form Virtual Chassis. You can bundle a max of 8 1Gig ports to form a LAG which acts as a VCP.
Reference: https://www.juniper.net/documentation/en_US/junos/topics/concept/virtual-chassis-ex4200-overview.html
I hope this helps.
Thanks,
Pradeep
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