Quality of service (QoS) in nondeterministic LAN
Sukanta Ganguly, Gurdeep Singh Hura · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2002
In this paper, the Quality-of-service (QoS) issue will be discussed for non-deterministic LAN (Ethernet). The Ethernet bandwidth has grown to 10 Gbps. IEEE will make formal specifications for the 10 Gbps Ethernet available around the second half of the year 2002. It is based on the CSMA/CD [6] and is a MAC-to-MAC protocol. The network interfaces have unique addresses called the MAC addresses. The manufacturers embed them in the MAC chip. Due to the limited view of the path for the Ethernet protocol, our approach will emphasize on bringing in some deterministic accessing of Ethernet segment using the time-slice approach. Instead of the sender sending the packet whenever it desires, it first needs to communicate with a master controller. The master controller will be the aggregation point, like a layer two Ethernet switch or a layer three switch/router or any node within the shared Ethernet segment. These are the nodes that build links between islands within the network. The master controller is responsible for assigning time slices to the sender node for sending in their data packets. During the assigned time slice only that nodes' packet is travelling via the network. In case of a active switch no high buffering capacity needs to be built into it as with the help of the time slicing mechanism the master controller has kept the rate of packet inflow equal to or less than the rate of packet outflow. Packet overflow will never happen in the aggregation point. But the most important aspect of this is that due to the deterministic nature of the link bandwidth and also with the help of our time based packet delivery mechanism guarantees can be provided about the time taken for a certain packet size to reach from one node to another. By summing up all the packet transfer time of all the intermediate nodes' an absolute time delivery system can be setup.