WFQ Flashcards
Where is WFQ used by default?
On slow speed interfaces < 2,048Kbps.
How are queues allocated?
A queue is allocated for each flow up to 256 flows by default.
Which value is used to provide weighting for WFQ?
IP Precedence values are used.
How does WFQ differ from FQ?
FQ prioritises based on packet size alone whereas WFQ considers the IP Precedence value also.
What is the formula used by WFQ to schedule packets?
Packets are scheduled by sequence numbers (lowest sent first). The sequence number is the weight of the packet multiplied by the number of bytes.
Weight = 32384 / (IP Precedence + 1).
Sequence number for a 96 byte packet with IP Precedence 5 is:
32384 / (5+1) * 96 = 518144.
What is the congestive discard threshold?
The number of packets that can be held in a queue i.e. the max queue depth.
What is the default congestive discard threshold?
64.
What is the default number of dynamic queues?
256
What are reservable conversation queues?
These queues are used for QoS features like RSVP.
What is the default number of reservable conversation queues?
0.
How is WFQ configured?
int serialx/x
fair-queue .
How can I see the queue stats for a serial interface?
show queue serialx/x
