Which statement is true about PFEs?
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A. B. C. D.B
PFE stands for Packet Forwarding Engine. It is a specialized component in Juniper Networks routers and switches that is responsible for processing and forwarding packets. The PFE is designed to operate independently and does not require an external CPU to perform packet forwarding functions.
Now, let's review each statement and determine which one is true about PFEs:
A. A PFE receives hardware status messages from the RE. This statement is true. The Routing Engine (RE) in a Juniper Networks router or switch is responsible for controlling the overall operation of the device. It receives input from various components, including the PFEs, and sends commands and messages to the PFEs to control their operation. One type of message that the RE sends to the PFEs is hardware status messages. These messages provide information about the status of the hardware components in the PFE, such as the status of interfaces, memory, and processors.
B. A PFE receives microcode updates from the RE. This statement is false. Microcode is firmware that is used to control the operation of hardware components, such as processors and network interfaces. Microcode updates are typically sent directly to the hardware components themselves, rather than to the PFE. In the case of Juniper Networks routers and switches, microcode updates are sent to the Packet Forwarding ASICs (PAs) that are integrated into the PFEs, rather than to the PFEs themselves.
C. A PFE receives environmental status messages from the RE. This statement is true. Environmental status messages are another type of message that the RE sends to the PFEs. These messages provide information about the status of the environmental components in the PFE, such as the temperature, power supply, and fan status.
D. A PFE receives layer 4 forwarding table updates from the RE. This statement is false. Layer 4 forwarding table updates are typically processed by the Control Plane components in a Juniper Networks router or switch, rather than by the PFE. The Control Plane is responsible for maintaining the routing table and forwarding table, and for processing routing protocols such as OSPF and BGP. The PFE is responsible for forwarding packets based on the information in the forwarding table, but it does not typically receive updates to the forwarding table directly from the Control Plane.
In conclusion, the statements that are true about PFEs are: