Three Categories of QoS Mechanisms

Question 1

Best effort

Answer 1

Best effort Best-effort treatment of traffic does not truly provide QoS to that traffic because there
is no reordering of packets. Best effort uses a first-in, first-out (FIFO) queuing strategy,
where packets are emptied from a queue in the same order that they entered the queue

Question 2

Integrated
Services
(IntServ)

Answer 2

Integrated
Services
(IntServ)
IntServ is often referred to as hard QoS because it can make strict bandwidth
reservations. IntServ uses signaling among network devices to provide bandwidth
reservations. Resource Reservation Protocol (RSVP) is an example of an IntServ
approach to QoS. Because IntServ must be configured on every router along a packet’s
path, the main drawback of IntServ is its lack of scalability

Question 3

Differentiated
Services
(DiffServ)

Answer 3

Differentiated
Services
(DiffServ)
DiffServ, as its name suggests, differentiates between multiple traffic flows.
Specifically, packets are marked, and routers and switches can then make decisions
(for example, dropping or forwarding decisions) based on those markings. Because
DiffServ does not make an explicit reservation, it is often called soft QoS. Most
modern QoS configurations are based on the DiffServ approach.