Second-level caching method and two-stage timeout flow table structure

Abstract

The invention provides a second-level caching method and a two-stage timeout flow table structure, and belongs to the field of information storage and network structures. The second-level caching method comprises the following steps: after a controller receives the data packet cache missing message, allocating a timeout to a corresponding flow rule of the data packet, updating relevant informationof the rule in an information base; then, the controller installing the flow rule into a main storage module of the switch and processing the data packet according to the action domain information ofthe rule, for example, forwarding or discarding, if the rule hits the data packet again before overtime and expiration, the flow rule being still kept in the main storage module, repeating the process until the rule is overtime and expired, storing the rule in the auxiliary storage module and recording the timeout value; if the flow rule hits the data packet in the auxiliary storage module, moving the flow rule to the main storage module, and the timeout value being not changed, otherwise, expelling the flow rule from the switch. The structure has the beneficial effects that the cache hit rate is greatly improved, the rule installation frequency is remarkably reduced, and the energy consumption of TCAM query is reduced.

Description

technical field [0001] The invention relates to a caching method, in particular to a secondary caching method based on software and hardware co-design, and also relates to a two-stage timeout flow table structure for realizing the secondary caching method. Background technique [0002] Software-Defined Network (SDN) achieves more centralized and flexible network management by decoupling the control plane and data plane. The current popular communication interface between control plane and data plane is OpenFlow[1]. The control plane is responsible for formulating packet forwarding policies, which are implemented as flow rules. When needed, the control plane installs some rules to the flow table of the data plane. In fact, the flow table on the data plane is equivalent to a cache of flow rules generated by the control plane. Different from traditional networks, network policies in OpenFlow are usually finer-grained and more dynamic, which puts high demands on efficient rule...

AI Technical Summary

Problems solved by technology

But the severe cost of forecasting errors and the difficulty of forecasting limit its effectiveness

Work analysis and observation in [7] that many flow rules of no value are installed unnecessarily wasting a lot of flow table space

However, studies have shown that in data centers, the duration of network flows varies widely, with a significant fraction of flows lasting less than a few hundred milliseconds [10]

Conservative timeout setti

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