QoS Scheduling and Policing

1. Answer

a. What is the difference between traditional RR and WFQ?

b. What are the four principles that form the basis for providing QoS in the Internet?

c. How does the leaky bucket mechanism help in regulating the traffic from a source?

d. A leaky bucket is represented as (r, b), what are r and b?

e. What is the maximum number of packets that can enter a network in any interval of length t, when the traffic flow is regulated by a leaky bucket (r, b)?

f. In WFQ, for a link with transmission rate R, class i (weight w_i) will always achieve a throughput of at least ___________. (use the term ‘Sum of ’ for the symbol ‘S ‘)

2. Answer

a. Average rate, and peak rate capture respectively the long-term and short-term traffic characteristics of a stream (true or false).

b. We combine the leaky bucket mechanism with the WFQ scheduling policy, so as to achieve a maximum bound on the delay for the flow in a router’s queue (true or false)