Question 430
An operator changes the outer VLAN priority marking at a PE. Observed: The 802.1p priority observed downstream no longer matches the agreed enterprise service class. What evidence would validate recovery from this precise failure mode?
Explanation
Correct Answer
The intended result is Downstream tag captures show the intended priority codepoint values. It specifically verifies recovery from an egress ieee 802.1p rewrite map is absent or maps the wrong forwarding class, which produced the original symptom: The 802.1p priority observed downstream no longer matches the agreed enterprise service class. It is stronger evidence than a generic interface-up indicator.
Incorrect Answers
This result is useful in another case with evidence Downstream peers see markings unchanged while reverse traffic is altered unexpectedly. It does not test recovery from the 802.1p priority observed downstream no longer matches the agreed enterprise service class. Check instead whether downstream tag captures show the intended priority codepoint values.
It confirms an unrelated service correction: The policer was attached to a shared filter term rather than the customer's scoped traffic. The present case reports The 802.1p priority observed downstream no longer matches the agreed enterprise service class. Its completion test is Downstream tag captures show the intended priority codepoint values.
That observation would verify a separate fault involving the firewall filter class action is attached on one ingress path but not the other. Its symptom is Traffic is classified correctly only on one interface even though both see identical flows. For this case the actual issue is an egress ieee 802.1p rewrite map is absent or maps the wrong forwarding class, and the relevant success signal is Downstream tag captures show the intended priority codepoint values.