Efficient and Order-Preserving Shifting of Data Streams

In order to exploit the capacity of parallel links we propose a traffic distribution scheme where each data stream is routed over one of the parallel links at a time. In cases of link overload or breakdown the network management entity should be able to shift selected data streams dynamically from one link to another according to some policy. Given that the source and sink of a data stream are able to deal with lost packets, but not with packets arriving out of order, the shifting has to be done in such a way that in-sequence delivery is guaranteed. In this paper we present two approaches that solve this task. The first method uses numbered shift commands that first have to be exchanged between the nodes before the actual shifting can take place. In the second method the shifting is only prepared by exchanging special commands. The actual shifting is done simply by using a prepared link. The methods are useful for remote bridges connecting remote LAN sites over several wide area networks, or for ATM switching nodes being connected by multiple links.