What is the difference between FIFO and WFQ?
“First-in-first-out (FIFO) queuing: A single queue is maintained at each output port. Weighted fair queuing (WFQ): takes into account the amount of traffic through each queue and gives busier queues more capacity without completely shutting out less busy queues.
What is WFQ in QoS?
WFQ is a flow-based queuing algorithm used in Quality of Service (QoS) that does two things simultaneously: It schedules interactive traffic to the front of the queue to reduce response time, and it fairly shares the remaining bandwidth between high bandwidth flows.
What is WFQ scheduling?
Weighted fair queueing (WFQ) is a network scheduling algorithm. Whereas FQ shares the link’s capacity in equal subparts, WFQ allows schedulers to specify, for each flow, which fraction of the capacity will be given.
How does weighted fair Queueing work?
The weighted fair queueing algorithm shares the processes within one packet transmission time regardless of the incoming pattern. Queueing is the result of congestion on an interface, which means the transmission ring is full and the interface is engaged in sending designated packets.
How does flow based WFQ WFQ differ from class based WFQ Cbwfq )?
The difference between WFQ and CBWFQ is that CBWFQ differentiates traffic by class (e.g., voice, data, or video) while WFQ differentiates traffic by flow (e.g., source and destination). WFQ offers fair queuing that divides the available bandwidth across active flows based on weights.
How does WFQ implement tail dropping?
WFQ uses a slightly modified tail-drop policy for choosing when to drop packets. WFQ places an absolute limit on the number of packets enqueued among all queues; this value is called the hold-queue limit. If a new packet arrives, and the hold-queue limit has been reached, the packet is discarded.
What is meant by weighted fair queuing WFQ )? Explain and discuss briefly?
Weighted fair queuing (WFQ) is a dynamic process that divides bandwidth among queues based on weights. The process is designed to be fair, such that WFQ ensures that all traffic is treated fairly with regard to its weight.
What is the essential difference between RR and WFQ packet scheduling?
The major difference between RR and WFQ: All packets get equal priority. Chapter 4, Problem 16RQ is solved.
Why do routers need queues?
Since the router’s memory is finite, a router can run out of space to accommodate freshly arriving packets. As part of the resource allocation mechanisms, routers must implement some queuing discipline that governs how packets are buffered or dropped when required.
Why is queuing theory important?
Queuing theory is important because it helps describe features of the queue, like average wait time, and provides the tools for optimizing queues. From a business sense, queuing theory informs the construction of efficient and cost-effective workflow systems.
What is difference between Round Robin and Weighted Fair queue?
Weighted Round Robin. The difference between the two is that WFQ services bits at each scheduling turn, whereas WRR handles packets in each scheduling turn. The number of packets to be serviced in each scheduling turn is decided by the weight of the queue.
How is WFQ used to allocate bandwidth?
To achieve WFQ’s goals for allocating link bandwidth, WFQ uses a scheduler that is actually pretty simple. The WFQ scheduler takes the packet with the lowest sequence number (SN) (also sometimes called finish time, or FT) when it needs to move the next packet to the hardware queue.
How does weighted fair queuing ( WFQ ) work?
Weighted Fair Queuing (WFQ) dynamically creates queues based on traffic flows and assigns bandwidth to these flows based on priority. The sub-queues are assigned bandwidths dynamically. Suppose 3 queues exist which have bandwidth percentages of 20%, 30%, and 50% when they are all active.
What kind of router does dwfq run on?
DWFQ runs only on Cisco 7000 series routers with an RSP-based RSP7000 interface processor or Cisco 7500 series routers with a VIP-based VIP2-40 or greater interface processor. (A VIP2-50 interface processor is strongly recommended when the aggregate line rate of the port adapters on the VIP is greater than DS3.
How are packets classified in A WFQ queue?
WFQ automatically classifies packets based on flows, with each flow being placed into a separate queue. For WFQ purposes, a flow is defined as all packets with the same values for the following: ■ Transport layer protocol (TCP or UDP)
