Having set up a connection and initiated the session, there appears to be a need for some mechanism to ensure quality is maintained across the network. The link capacity must be maintained and the QoS function to ensure the tasks undertaken can be completed using the available resources. The QoS is the last step before the resources are granted for use by the process. To perform its functions, various protocols are used, such as IntServ and DiffServ. IntServ utilizes the Resource Reservation Protocol (RSVP) to make requests and reservations for resources across a network.
This mechanism works best without the huge burden created by broadband connections. Using the IntServ algorithm, the packets received could be reshaped to meet the channel requirements. This is because RSVP does not specify how resources are to be reserved. This leaves a huge overhead of measuring resources constantly and making reservations accordingly. This is the reason behind the reduction in the use of this method.
DiffServ, on the other hand, is an approach that marks packets received based on the type of service they require. In response to these markers, routers and switchers can utilize various queuing strategies to best meet these requirements. Routers supporting this algorithm maintain packets in different queues where resources are granted based on priority. Packets are then handed in based on the allocated priority. In line with this token leaking bucket, mechanisms are used to manage the traffic.
In the token bucket scheme, a token (packet) is added to the bucket every r seconds. The bucket is already known to be able to hold b number of tokens. If a token is received after the bucket is full, it is discarded. In the leaky bucket algorithm, the packets are gradually sent across the network in bits. If the bit is larger than the allocated portion, then it is discarded. Using this approach when the bucket is full additional bits will be discarded. In the leaky bucket algorithm, packets must conform to a specified size, or else they are discarded.