Troubleshooting Common Configuration Problems; A Map Becoming Inactive - HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual

controls the amount of traffic passed to the lower-speed WAN interfaces. Rate
limiting Ethernet traffic prevents the router from receiving and processing a
great number of packets that it will only have to drop.
The show queue command also displays the number of currently active
conversations on an interface as well as the highest number of conversations
ever active at once. Remember that the effect of WFQ can be diluted by a large
number of queues. If you find that an interface is constantly using an excessive
number of subqueues, you should consider configuring LLQ for real-time
traffic (if you have not already done so).
If the interface is only implementing WFQ, you should also consider config-
uring CBWFQ: scan through the queues, look for common criteria, and group
several queues into a class.

Troubleshooting Common Configuration Problems

Common problems you may encounter while configuring QoS policies on your
router include:
the map becoming inactive
an Ethernet interface refusing to take a QoS map

A Map Becoming Inactive

The Secure Router OS will only activate a map if the interface has sufficient
bandwidth to grant every queue established in the map the guaranteed rate.
By default, the bandwidth available for special queues on an interface is 75
percent of the interface's speed.
If you use the percent or remaining percent keywords to set the bandwidth,
the Secure Router OS will not allow you to exceed the limit. However, if you
use absolute bandwidths, the Secure Router OS will not recognize the problem
until you assign the QoS map to the logical interface. The Secure Router OS
will deactivate a map that guarantees more bandwidth than an interface has
available.
When you use the percent keywords to configure CBWFQ in conjunction with
low-latency queues, you may also inadvertently exceed an interface's available
bandwidth. For example, a Frame Relay interface is bound to a single E1 line.
You allocate 60 percent of the interface's bandwidth (1.23 Mbps) to several
CBWFQ classes. You also guarantee a low-latency queue 600 Kbps, bringing
the total up to 1.83 Mbps and exceeding the 1.536 Mbps limit. When you assign
the map to the Frame Relay interface, the router will force the map to become
inactive.
Setting Up Quality of Service
Monitoring QoS
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