SRX

where does IOC / NPC / SPC / and SCB  for high end SRX gateway reside in the Control Plane / Forwarding Plan architectre of Junos ?

Is there a major difference between NPC and SCB functions ? I see that both of them control the IOCs ?

I'm trying to understand the operations of these modules and what exactly the major functions of each ?

Thanks in advance.

The RE (route engine) acts as the control plane for the box. The rest of the modules are the forwarding plane.

SPC carries the processor (SPU) that provides advanced services (firewall, IPS, VPN, etc).

IOC carries the physical ports.

NPC carries the chip (NPU) that does basic packet processing (packet ordering, policing/simple filtering, most screen functions, etc).

On the SRX5000, the NPU is included with the IOC; on the SRX1k/3k, there were constraints that forced engineering to separate IOC/NPC into separate cards.

The SCB is the actual switching fabric that allows all the cards to communicate; it's nothing more than L2 connectivity (with a some QoS and other internal functions) between the various cards in the chassis.

The SRX1400 is the only high-end SRX that doesn't have a switch fabric; inter-module communication occurs through the Broadcom switching chip on the onboard interface card.

That helped alot ! thank you !