ATM上实现MPLS流合并技术

在多协议标签交换（MPLS）网络中，ATM－LSR的VC合并机制能把多个IP流映射到同一个VC标签上进行转发，增强了网络的可扩展性，对已提出的一些ATM网络VC合并机制进行了研究，分析了这些技术存在的主要问题，如需要额外的缓存、协议开销及时延，导致不能保证业务的QoS需求等，最后对ATM信元头负载类型域的两们进行重编码，提出了一种新的支持MPLS VC合并的调度方法，使得信元既可以交错，又能唯一区分，其主要特点为：实现简单；不需要额外的缓存和协议开锁；能保证基于流的QoS，但是，它使用了近似GPS的循环调度机制，在负载较低时带宽利用率略有下降。

Study of MPLS StreamMerging over ATM

In Muhiprotocol Label Switching (MPLS), VC-merging enables multi IP flows to be mapped onto the same VC label if they have the same destination. It provides a scalable solution for the network growth. This paper studied several approaches having been proposed to this day and analyzed their main problems, such as the additional buffering, protocol overhead, delay etc. , which make the provision of QoS difficult to achieve. With the help of reoding two bits inside the head of ATM cell, this paper put forward a new MPLS VC-merge capable scheduler. It allows cells to be interleaved with one another and be uniquely identified. The new scheduler has several properties: ① simple to implement, ② requiring no extra buffer and protocol overhead, ③ maintaining perflow QoS. However, it may introduce a minimal waste of link bandwith when utilization is low due to the approximately GPS round robin scheduler it uses.