Which statement describes exception traffic?
Click on the arrows to vote for the correct answer
A. B. C. D.C
Exception traffic refers to packets that need to be processed differently than normal forwarding traffic. These packets include control plane traffic, such as routing protocols and management traffic, and packets that do not match any forwarding rules in the forwarding table.
Now, let's look at the given options and their descriptions:
A. Exception traffic must be sent to the PFE for processing. This statement is partially correct. When a packet matches a control plane filter, it is sent to the Packet Forwarding Engine (PFE) for processing. However, not all exception traffic needs to be sent to the PFE. For example, packets that do not match any forwarding rules are processed by the Routing Engine (RE) and do not need to be sent to the PFE.
B. Exception traffic enters one ingress port and is sent out multiple egress ports. This statement is incorrect. Exception traffic does not necessarily enter one ingress port and is not sent out multiple egress ports. Exception traffic is processed based on the forwarding rules and can be sent out of any egress port, depending on the forwarding table.
C. Exception traffic is rate-limited on the internal link to prevent DoS attacks. This statement is partially correct. Exception traffic is often rate-limited to prevent Denial of Service (DoS) attacks on the control plane. However, this is not always the case and depends on the specific configuration.
D. Exception traffic is processed after forwarding traffic when congestion exists. This statement is correct. When congestion occurs, forwarding traffic is given priority over exception traffic. Exception traffic is processed only after the forwarding traffic has been processed.
Therefore, the correct answer is D.