What is the purpose of queueing?
A. Queueing is designed to accommodate temporary congestion on a network device’s interface by storing excess packets in buffers until bandwidth becomes available. Cisco IOS routers support several queueing methods to meet the varying bandwidth, jitter, and delay requirements of different applications. The default mechanism on most interfaces is First In First Out (FIFO). Some traffic types have more demanding delay/jitter requirements. Thus, one of the following alternative queueing mechanisms should be configured or is enabled by default: • Weighted Fair Queueing (WFQ) • Class-Based Weighted Fair Queueing (CBWFQ) • Low Latency Queueing (LLQ), which is in fact CBWFQ with a Priority Queue (PQ) (known as PQCBWFQ) • Priority Queueing (PQ) • Custom Queueing (CQ) Queueing generally happens on outbound interfaces only. A router queues packets that are going out an interface. You can police inbound traffic, but usually you cannot queue inbound (an exception is receive-side buffering on a Cis
