I/O Cards (IOCs) are common form-factor module (CFM) cards that provide additional physical network connections to the services gateway to supplement the Ethernet ports on the Switch Fabric Board (SFB). Their primary function is to deliver data packets arriving on the physical ports to the Network Processing Card (NPC) and to forward data packets out the physical ports after services processing. The SRX 3400 has four slots in the front of the chassis where you can install IOCs. The SRX 3600 services gateway has six CFM slots in the front of the chassis where you can where you can install IOCs. You can install any combination of IOCs in the slots.
The SRX 3400 and SRX 3600 supports the following types of IOCs: