Multi-topology routing (MTR) provides an attractive alternative to segment routing for traffic engineering when network devices cannot be upgraded. However, due to a high overhead in terms of link state messages exchanged by topologies and the need to frequently update link weights to follow evolving network conditions, MTR is often limited to a small number of topologies and the satisfaction of loose QoS constraints. To overcome these limitations we propose vMTR, an MTR extension where demands are routed over virtual topologies that are silent, i.e., they do not exchange LSA messages, and that are continuously derived from a very limited set of real topologies, optimizing each a QoS parameter. In this context, we present a polynomial and exact algorithm for vMTR and, as a benchmark, a local search algorithm for MTR. We show that vMTR helps reducing drastically the number of real topologies and that it is more robust to QoS changes.

翻译：多拓扑路由（MTR）在网络设备无法升级时，为流量工程提供了一种比段路由更具吸引力的替代方案。然而，由于拓扑间交换的链路状态消息带来高昂开销，且为适应不断变化的网络条件需频繁更新链路权重，MTR通常局限于少量拓扑和宽松QoS约束的满足。为克服这些限制，我们提出vMTR——一种MTR扩展方案，其中需求经由静默虚拟拓扑路由（即不交换LSA消息），这些虚拟拓扑从极少数实际拓扑中持续衍生，并分别优化某一QoS参数。在此背景下，我们为vMTR提出一种多项式精确算法，并以MTR的局部搜索算法作为基准。实验表明，vMTR能大幅减少实际拓扑数量，且对QoS变化具有更强鲁棒性。