ITU-T Rec. Y.1541 defines a set of QoS classes for IP-based networks. Two of the Y.1541 classes have an IP packet transfer delay (IPTD) objective of 400 ms (class 1 and class 3) and two have a more stringent IPTD objective of 100 ms (class 0 and class 2). When supporting the transfer of IP packets over an ATM network, I.356 class 1 (stringent class) and class 5 (stringent bi-level class), both of which have a CTD objective of 400 ms, are obvious candidates for supporting Y.1541 classes 1 and 3. As there are no I.356 classes with an end-to-end CTD of 100 ms, support of Y.1541 QoS classes 0 and 2 requires more consideration. This appendix offers guidance on how ATM networks conforming to ITU-T Rec. I.356 can be configured to support the stringent delay Y.1541 QoS classes.