An access terminal (AT) and a data-optimized cellular communication radio network (RN) negotiate a set of packet sizes for use on a reverse link between the AT and the RN. The negotiated set of packet sizes may differ from the default set of packet sizes defined in an existing standard, such as 1xEV-DO Revisions A and B. The packet sizes in the negotiated set may be tailored to provide a good fit with an application transmitting data on the reverse link, such as a voice encoder of a voice over Internet Protocol (VoIP) application. The AT and the RN communicate using the negotiated set of packet sizes. The packet sizes of the negotiated set may be mapped to the same reverse rate indicator (RRI) channel codewords as are defined in systems operating under the standard. Packing efficiency is thus increased, and higher capacity for delay-sensitive applications is achieved.