Abstract: This paper proposes a Priority-based Lateral Error Recovery（PLER） model in application layer multicast.In PLER，nodes are divided into a number of groups，each of which forms an independent group.Since error correlation across groups is low，a node effectively recovers its error by “laterally” requesting retransmission from nearby nodes in other groups.Using Internet-like topologies，this paper shows via simulations that PLER is an effective error recovery mechanism.As compared with traditional recovery schemes，PLER achieves much lower average link stress and attains much lower residual loss rate.

Key words: priority, application layer multicast, lateral error recovery

摘要： 提出了一种基于优先级的应用层组播横向差错恢复PLER（Priority-based Lateral Error Recovery）模型。该模型把节点划分为多个独立的组，由于组间的错误关联度低，节点通过请求邻近节点来“横向”重传数据可以有效地恢复差错。仿真实验结果表明，与传统的恢复模型相比，PLER能够更有效减少平均链路压力，降低二次丢失率。

关键词: 优先级, 应用层组播, 横向差错恢复