Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> CAMs are the most popular practical method for implementing packet classification in high performance routers. Their principal drawbacks are high power consumption and inefficient representation of filters with port ranges. A recent paper [Narlikar, et al., 2003] showed how partitioned TCAMs could be used to implement IP route lookup with dramatically lower power consumption. We extend the ideas in [Narlikar, et al., 2003] to address the more challenging problem of general packet classification. We describe two extensions to the standard TCAM architecture. The first organizes the TCAM as a two level hierarchy in which an index block is used to enable/disable the querying of the main storage blocks. The second incorporates circuits for range comparisons directly within the TCAM memory array. Extended TCAMs can deliver high performance (100 million lookups per second) for large filter sets (100,000 filters), while reducing power consumption by a factor of ten and improving space efficiency by a factor of three. <s> BIB001 </s> Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> Ternary content addressable memories (TCAMs) have become the de facto standard in industry for fast packet classification. Unfortunately, TCAMs have limitations of small capacity, high power consumption, high heat generation, and high cost. The well-known range expansion problem exacerbates these limitations as each classifier rule typically has to be converted to multiple TCAM rules. One method for coping with these limitations is to use compression schemes to reduce the number of TCAM rules required to represent a classifier. Unfortunately, all existing compression schemes only produce prefix classifiers. Thus, they all miss the compression opportunities created by non-prefix ternary classifiers. In this paper, we propose bit weaving, the first non-prefix compression scheme. Bit weaving is based on the observation that TCAM entries that have the same decision and whose predicates differ by only one bit can be merged into one entry by replacing the bit in question with . Bit weaving consists of two new techniques, bit swapping and bit merging, to first identify and then merge such rules together. The key advantages of bit weaving are that it runs fast, it is effective, and it is composable with other TCAM optimization methods as a pre/post-processing routine. We implemented bit weaving and conducted experiments on both real-world and synthetic packet classifiers. Our experimental results show the following: 1) bit weaving is an effective standalone compression technique (it achieves an average compression ratio of 23.6%); 2) bit weaving finds compression opportunities that other methods miss. Specifically, bit weaving improves the prior TCAM optimization techniques of TCAM Razor and Topological Transformation by an average of 12.8% and 36.5%, respectively. <s> BIB002 </s> Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> Low latency lookup (typically single cycle) has made Ternary Content Addressable Memory (TCAM) indispensable in high performance network switching devices. However, high power dissipation of TCAM makes it incongruous in switches for today’s power sensitive emerging network framework, viz., Software Defined Network (SDN). In this paper we propose Compact TCAM, an approach that reduces the size of the flow entries in TCAM. We use shorter tags for identifying flows than the original number of bits used to store the flow entries for SDN switches. We leverage the dynamic programming capability of SDN to route the packets using these tags. We show that our approach can be easily implemented using the new SDN framework while optimizing the TCAM space. Our experiments with real world and synthetic traffic show average reduction of TCAM power by 80% in SDN switching devices for a given number of flows. <s> BIB003 </s> Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> In software-defined networks (SDNs), the network controller first formulates abstract network-wide policies, and then implements them in the forwarding tables of network switches. However, fast SDN tables often cannot scale beyond a few hundred entries. This is because they typically include wildcards, and therefore are implemented using either expensive and power-hungry TCAMs, or complex and slow data structures. This paper presents the Palette distribution framework for decomposing large SDN tables into small ones and then distributing them across the network, while preserving the overall SDN policy semantics. Palette helps balance the sizes of the tables across the network, as well as reduce the total number of entries by sharing resources among different connections. It copes with two NP-hard optimization problems: Decomposing a large SDN table into equivalent subtables, and distributing the subtables such that each connection traverses each type of subtable at least once. To implement the Palette distribution framework, we introduce graph-theoretical formulations and algorithms, and show that they achieve close-to-optimal results in practice. <s> BIB004 </s> Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> Software-Defined Networking (SDN) enables fine-grained policies for firewalls, load balancers, routers, traffic monitoring, and other functionality. While Ternary Content Addressable Memory (TCAM) enables OpenFlow switches to process packets at high speed based on multiple header fields, today's commodity switches support just thousands to tens of thousands of rules. To realize the potential of SDN on this hardware, we need efficient ways to support the abstraction of a switch with arbitrarily large rule tables. To do so, we define a hardware-software hybrid switch design that relies on rule caching to provide large rule tables at low cost. Unlike traditional caching solutions, we neither cache individual rules (to respect rule dependencies) nor compress rules (to preserve the per-rule traffic counts). Instead we ``splice'' long dependency chains to cache smaller groups of rules while preserving the semantics of the network policy. Our design satisfies four core criteria: (1) elasticity (combining the best of hardware and software switches), (2) transparency (faithfully supporting native OpenFlow semantics, including traffic counters), (3) fine-grained rule caching (placing popular rules in the TCAM, despite dependencies on less-popular rules), and (4) adaptability (to enable incremental changes to the rule caching as the policy changes). <s> BIB005 </s> Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> Software-Defined Network (SDN) is a promising network paradigm that separates the control plane and data plane in the network. It has shown great advantages in simplifying network management such that new functions can be easily supported without physical access to the network switches. However, Ternary Content Addressable Memory (TCAM), as a critical hardware storing rules for high-speed packet processing in SDN-enabled devices, can be supplied to each device with very limited quantity because it is expensive and energy-consuming. To efficiently use TCAM resources, we propose a rule multiplexing scheme, in which the same set of rules deployed on each node apply to the whole flow of a session going through but towards different paths. Based on this scheme, we study the rule placement problem with the objective of minimizing rule space occupation for multiple unicast sessions under QoS constraints.We formulate the optimization problem jointly considering routing engineering and rule placement under both existing and our rule multiplexing schemes. Finally, extensive simulations are conducted to show that our proposals significantly outperform existing solutions. <s> BIB006 </s> Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> Software-defined Networks (SDN), in particular OpenFlow, is a new networking paradigm enabling innovation through network programmability. Over past few years, many applications have been built using SDN such as server load balancing, virtual-machine migration, traffic engineering and access control. In this paper, we focus on using SDN for energy-aware routing (EAR). Since traffic load has a small influence on power consumption of routers, EAR allows to put unused links into sleep mode to save energy. SDN can collect traffic matrix and then computes routing solutions satisfying QoS while being minimal in energy consumption. However, prior works on EAR have assumed that the table of OpenFlow switch can hold an infinite number of rules. In practice, this assumption does not hold since the flow table is implemented with Ternary Content Addressable Memory (TCAM) which is expensive and power-hungry. In this paper, we propose an optimization method to minimize energy consumption for a backbone network while respecting capacity constraints on links and rule space constraints on routers. In details, we present an exact formulation using Integer Linear Program (ILP) and introduce efficient greedy heuristic algorithm. Based on simulations, we show that using this smart rule space allocation, it is possible to save almost as much power consumption as the classical EAR approach. <s> BIB007 </s> Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> An SDN enabled mobile access network is a future network with great potential to support scalable and flexible network applications. To support various network applications, the SDN-enabled mobile access network usually uses forwarding rules in SDN devices. With a limited rule space in existing SDN devices, a rule caching mechanism is an efficient way to improve network performance. In this article we propose SRCMN, which is a new caching structure to improve network performance with a limited rule space in the SDN-enabled mobile access network. We design a two-layer rule space in each SDN device, which is managed by the SDN controller. We also design a cache prefetching mechanism with the consideration of user mobility. By conducting extensive simulations, we demonstrate that our proposed structure and mechanism significantly outperform original rule space management under various network settings. <s> BIB008 </s> Software Defined Networking Architecture, Security and Energy Efficiency: A Survey <s> 5) Ternary Content Addressable Memory (TCAM) Compression for Energy Efficiency and Network Security: <s> We present Dionysus, a system for fast, consistent network updates in software-defined networks. Dionysus encodes as a graph the consistency-related dependencies among updates at individual switches, and it then dynamically schedules these updates based on runtime differences in the update speeds of different switches. This dynamic scheduling is the key to its speed; prior update methods are slow because they pre-determine a schedule, which does not adapt to runtime conditions. Testbed experiments and data-driven simulations show that Dionysus improves the median update speed by 53--88% in both wide area and data center networks compared to prior methods. <s> BIB009
The rules that are to be implemented in the SDN are stored in flow table present in Ternary content addressable memory (TCAM). It can compare all incoming flows parallelly and enable quick packet processing BIB005 . The number of the entries in the flow table are limited as the TCAM usage is associated with cost factor. TCAM is expected to impose the burden of 400 times more cost and 100 times more power usage BIB001 than the traditional memory storage devices such as RAM. The other main concerning issue of TCAM is its update time that is limited to 40−50 rule-tables per second BIB008 ,  , BIB009 . Compact TCAM has been proposed in BIB003 that condenses the structure of TCAM by lowering the size of the flow IDs in a flow table. The flows assigned with a specific flow ID for the purpose of identification. The other advantage of the compact TCAM includes the usage of SDN for removal of redundant information. By the implementation of compact TCAM method 80% of the power reduction can be achieved. TCAM razor has been proposed in  to reduce number of flow entries in the flow table by implementing four step mechanism that compresses the TCAM by 29.0% which leads to the savings of 54% energy. In this method multidimensional rules are fragmented into many one dimensional rule lists. BitWeaving has been proposed in BIB002 as a non-prefix ternary classifier implemented for the compression of rules in TCAM using two different approaches: bit swapping and bit merging. In this method flow entries with same decision and just differ by the single bit can be combined together. BitWeaving method was able to achieve the compression ratio of 23.6% with high speed and energy efficiency BIB002 . Palette distribution BIB004 has been proposed to offer a solution for rule placement problem by breaking the large SDN tables into small sub-tables using pivot bit decomposition. As all rules cannot be stored under the single network they are divided and distributed among the multiple networks under SDN. Joint optimization method has been proposed in BIB006 that uses both rule allocation and traffic engineering to achieve energy optimization and security in the network. Integer Linear Program has been proposed in BIB007 that uses greedy heuristic method for achieving the energy saving. Though the software switches can eliminate the issues such as high cost and can also update the flow tables up to 10 times quicker than the hardware switches, they are associated with some delay in the packet processing. CacheFlow has the hybrid switch embedded with both features of hardware and software switches BIB008 ,  that offers energy efficient solutions.