Editing Traffic contract (section)

== Quality of service parameters ==

A set of parameters are negotiated when a connection is set up in an ATM network. These parameters are used to measure the QoS of a connection and quantify end-to-end network performance at the ATM layer. The network should guarantee the negotiated QoS by meeting certain values of these parameters.

*''Cell Transfer Delay'' (CTD). The delay experienced by a cell between the time it takes for the first bit of the cell to be transmitted by the source and the last bit of the cell to be received by the destination. Maximum Cell Transfer Delay (Max CTD) and Mean Cell Transfer Delay (Mean CTD) are used.
*''Peak-to-peak Cell Delay Variation'' (CDV). The difference between the maximum and minimum CTD experienced during the connection. Peak-to-peak CDV and Instantaneous CDV are used.
*''Cell Loss Ratio'' (CLR). The percentage of cells that are lost in the network due to error or congestion and are not received by the destination.