How is bandwidth reserved in a LLQ?

[pweinhold]

Hi,

I'm wondering how bandwidth can be "reserved" in a LLQ. For example, say I build the following policy map that puts voice traffic in a LLQ and also reserves 20% of a circuit's bandwidth:

policy-map QUEUE_SERVICE_EGRESS

class VOICE_EF

priority percent 20

Since packets in a strict priority queue are always sent ahead of any other packets, how can you say that 20% of the interface bandwidth is "reserved"? Wouldn't the LLQ always get 100% of the bandwidth, until the LLQ was empty?

[pweinhold]

I already got an answer to this question:

The priority percent syntax is misleading, because it's similar to the bandwidth percent syntax. But with the priority queue, traffic is not reserved, but rather capped at that percentage. That's because priority queue traffic will always get 100% of an interface's bandwidth, so you have to cap it so it doesn't starve the other traffic.