Avaya 580 Manual Do Utilizador

24-6

User Guide for the Avaya P580 and P882 Multiservice Switches, v6.1

Chapter 24

High Priority 
Allocation

Displays the percent of the buffer’s queuing space allotted to 
high priority traffic. Because the high-priority queue is 
serviced more frequently than the normal priority queue, 
raising this value may not necessarily provide better service. 
In fact, if you are using the high-priority queue for delay-
sensitive traffic, you may want to reduce the amount of 
memory devoted to the high-priority queue. This ensures that 
packets that cannot be delivered in a timely manner are 
discarded. If you want the high priority queue to guarantee 
delivery of as many packets as possible, regardless of delay, 
increase this value. The change does not take effect until you 
reset the switch.

Priority 
Threshold

Allows you to set this parameter to the value at which the 
switch starts sending packets to the high-priority queue. The 
default value (4) causes all traffic with a priority greater than 
or equal to 4 (4, 5, 6, and 7) to be assigned to the high-
priority queue. Priority schemes have more than two queues 
(the IEEE allows up to 8, numbered 0 through 7). Avaya 
recommends that you do not change this parameter.

High Priority 
Service Ratio

Allows you to set how many times the high priority queue is 
serviced for each time the low priority queue is serviced. The 
ideal value changes from queue to queue, but the goal is to 
ensure that traffic mix guarantees optimal mix between high-
priority and best effort traffic.

High and 
Normal 
Overflow Drops

Displays the number of packets dropped because the 
associated buffer is full. Indicates that the device 
immediately before the queue is processing traffic faster than 
the next downstream element can process the same volume 
of traffic. For example, overflow drops on the input buffer 
indicate that traffic is arriving faster than the switch matrix 
can process it. Overflow drops on the output buffers 
indicates that the output port cannot handle the volume of the 
load being offered.

High and 
Normal Stale 
Drops

Displays the number of packets dropped because they timed 
out waiting for service (using the age timer value). In the 
high-priority queue, this can help determine how efficiently 
the switch is processing “better never than late” traffic. 
Excessive stale drops on the high-priority queue may 
indicate the need to increase the service ratio on the high-
priority queue.

Congestion 
Drops

Displays the number of packets dropped because the switch 
controller has sensed congestion at the outbound port.