We recently saw this article:
Understand Special Queues With Non-RSP Platform
As noted in the Packet Prioritization Tags and Queuing table, Cisco router platforms like the Cisco 7200, 3600 and 2600 series place pak_priority messages into a separate set of queues and not the class-default set of queues.
QoS and Locally Generated Packets
Traffic generated by the router represents a special case for outbound QoS service policies. Some locally generated traffic must be treated as any other user traffic, and the QoS system must apply the configured QoS mechanisms to this traffic. An example of such traffic is performance probes that are designed to measure the behavior incurred by packets of a given class. Other locally generated traffic, particularly Layer 2 keepalives and routing protocol messages, are vital to the basic functioning of the router and must not be subject to some QoS features. For example, weighted random early detection (WRED) must not drop Layer 2 keepalives when the average queue depth reaches a high watermark
In addition, packets destined to the router must be handled carefully. For example, remember that a service-policy that applies class-based policing must not apply to packets destined to the router to avoid dropping important control messages.
If I read it correctly, we do not need a specific QOS policy for routing updates and control traffic.
The problem is, 2 years ago we rolled out the first QOS policy on 2651 routers. OSPF adjacencies were dropped during periods of congestion. One engineer finally marked OSPF traffic and put it in the priority queue, and the problems stopped.
This seems to contradict what the article was saying. We even had a Cisco rep on site for another project and we ran the question past him. He said that OSPF routing is treated differently and that we didn't need to include it in the QOS policy.
Does anyone have a good answer to this one? (thanks in advance)