In this paper, an efficient traffic allocation technique and a slotted delay-sensitive WDMA protocol suitable for ring metropolitan area networks is proposed. Our purpose is to improve the limited bandwidth utilization that many WDMA protocols for MANs introduce, especially at high loads. This is achieved by: 1) applying an access algorithm to avoid data wavelengths and receiver collisions, and 2) introducing a multiple buffer architecture at each node with an effective buffer selection for transmission scheme that combines the priority criteria of receiver collisions avoidance and packet age. Thus, we obtain not only dropping probability and delay reduction, but also significant throughput enhancement. The required number of buffers per node to maximize throughput is investigated. Performance evaluation is provided by a discrete event simulation model based on self-similar traffic. Comparative results prove that the proposed architecture manages efficient bandwidth utilization as compared with other WDMA protocols, especially under high loads.