What kind of output scheduling do the Catalyst 4500/4000 switches that run CatOS provide?
A. Line cards of Catalyst 4500/4000 switches that run CatOS support two output queues per port with one threshold at 100 percent. This 2 Queues, 1 Threshold (2Q1T) method is not configurable. It does offer user configuration for Class of Service (CoS) value maps for the two queues. For example, you can configure packets with a CoS value of 0–3 to use the first queue and 4–7 to use the second queue. Catalyst 4500/4000 only supports CoS mappings in pairs, 0–1, 2–3, 4–5, 6–7. You cannot set one CoS value unless you specify the corresponding partner CoS. For example, you cannot specify 0–4 for the first queue because you must pair 5 with the partner, 4. The two queues are serviced in a round-robin fashion. Refer to the Installation and Configuration Note for the Catalyst 4000 Layer 3 Services Module for additional information on Layer 3 module features. For Catalyst 4500/4000 switches that run Cisco IOS Software features, refer to the document Understanding and Configuring QoS.
Related Questions
- Can the Catalyst 4500/4000 switches that run CatOS change the incoming Class of Service (CoS) value in IEEE 802.1Q (dot1q) tags?
- What is the minimum software that is necessary for QoS on Catalyst 4500/4000 switches that run CatOS?
- What kind of input scheduling do the Catalyst 4500/4000 switches that run CatOS provide?
