Implementation of IPv6 ToS over ATM Network

The current Internet infrastructure uses Internet Protocol version 4 (IPv4) that only supports the “best-effort” Qualityof-Service (QoS). While this simplification of QoS requires small processing latency in routers, there is no distinction between packets with various delay requirements. The introduction of the Type of Service (ToS) field in Internet Protocol version 6 (IPv6), addresses this deficiency. The feasibility of mapping IPv6 ToS onto various Asynchronous Transfer Mode (ATM) service categories has been recently suggested. We investigate the application and the mapping of the IPv6 ToS onto various ATM QoS classes. Our goal is to use the OPNET simulation tool to verify the interoperability of IPv6 ToS and ATM QoS service categories. In our implementation, IPv6 packets may be switched and delivered to their destination based on the specified ToS header fields. The simulation results indicate that such an IPv6-over-ATM network could deliver IPv6 packets according to their specified ToS, and that packets with distinct ToS will experience different end-to-end network delays.