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摘要
In the Locator/ID separation protocol (LISP) network, mapping caches are usually used in Ingress tunnel routers to cache recently used identifier-to-locator mappings of remote hosts. When the original mapping in the Egress tunnel router changes, it introduces the problem of cache consistency. In general, the mapping cache supports weak cache consistency by using the time-to-live (TTL) mechanism. However, a stale mapping could lead the packets to a wrong destination. In this paper, we first evaluate the performance of TTL by trace-driven simulation and the results indicate that maintaining strong mapping cache consistency has become an indispensable mechanism in the LISP network. Then we design the lease algorithm to realize the strong consistency and propose analytical models to decide the lease duration based on the state space overhead and the control message overhead, respectively. We present numerical results to estimate the mapping change frequency, to show the impact of different parameters on the lease duration and to explore the relationship between the state space and control message overhead. Finally, we do the trace-driven simulation to compare the lease algorithm to polling-every-time and invalidation in terms of the state space and control messages. The lease algorithm with an appropriate lease duration can balance the state space and the control message overhead while providing strong mapping cache consistency.
- 出版日期2014-6
- 单位中国科学院信息工程研究所; 北京交通大学
