In most cases, you can install PICs of different media types on the same FPC as long as the FPC and the routing platform support those PICs. However, configuration rules might limit certain combinations of PICs on some platforms. If you have different PIC families on a single FPC and are running JUNOS 6.3 or later, review the configuration rules to plan which PICs to install on the FPCs for your routing platform. Consult the most recent technical bulletins about configuration rules for PIC combinations on the Juniper Networks Support site at https://www.juniper.net/support/. Newer JUNOS services for some PICs can require significant Internet Processor ASIC memory. Ethernet and SONET PICs typically do not use large amounts of memory. Gigabit Ethernet, ATM2, IQ serial PICs, and Adaptive Services PICs use more. To conserve memory, you can group PICs in the same family together on the same FPC.
When you upgrade to JUNOS Release 7.5 or later, a warning appears if any configuration rules affect your PIC combinations. If you continue the installation, one or more PICs might appear to be online (the LEDs are on), but the JUNOS software cannot enable them and they cannot pass traffic. As a workaround, you can: