  With the sharp growth of cloud services and their possible combinations, the
scale of data center network traffic has an inevitable explosive increasing in
recent years. Software defined network (SDN) provides a scalable and flexible
structure to simplify network traffic management. It has been shown that
Ternary Content Addressable Memory (TCAM) management plays an important role on
the performance of SDN. However, previous literatures, in point of view on rule
placement strategies, are still insufficient to provide high scalability for
processing large flow sets with a limited TCAM size. So caching is a brand new
method for TCAM management which can provide better performance than rule
placement. In this paper, we propose FDRC, an efficient flow-driven rule
caching algorithm to optimize the cache replacement in SDN-based networks.
Different from the previous packet-driven caching algorithm, FDRC is
characterized by trying to deal with the challenges of limited cache size
constraint and unpredictable flows. In particular, we design a caching
algorithm with low-complexity to achieve high cache hit ratio by prefetching
and special replacement strategy for predictable and unpredictable flows,
respectively. By conducting extensive simulations, we demonstrate that our
proposed caching algorithm significantly outperforms FIFO and least recently
used (LRU) algorithms under various network settings.
