[c-nsp] LLQ question

[Nigel Camp]

Hi all,

I have just read a couple of conflicting articles regarding LLQ and was 
hoping for a definite answer.

Some sources say that LLQ can't burst past the configured bandwidth / 
percentage, while others say it can.

Here are a couple of examples...

 From http://tinyurl.com/7e89a under the "Guaranteed Bandwidth" heading:

  Priority traffic metering has the following qualities:

     * It is much like Committed Access Rate's (CAR) rate limiting, 
except that priority traffic metering is only performed under 
congestion conditions. When the device is not congested, the priority 
class traffic is allowed to exceed its allocated bandwidth. When the 
device is congested, the priority class traffic above the allocated 
bandwidth is discarded.

This contradicts the Cisco press Cisco Qos Exam Certification Guide 
Second Edition section on LLQ, which states on page 308:

" The priority command sets the guaranteed minimum bandwidth, which is 
also the maximum bandwidth! As mentioned earlier, LLQ polices the 
traffic and in a class that uses the priority command and discards 
excess traffic.

It was my understanding that a link not experiencing congestion would 
allow the burst, but now i'm not so sure.

Thanks in advance.

Regards,
Nigel