Impact of TCAM size on power efficiency in a network of OpenFlow switches

Abstract

Recent developments in networking include the interest in software-defined networking, in which OpenFlow switches are in charge of forwarding traffic by matching incoming packets with forwarding rules in their flow tables. Flow tables are commonly implemented in ternary content addressable memories (TCAMs). Typically, this type of memory tends to be extremely expensive and to be power-hungry devices. The price and power dissipation of TCAM depend on the capacity of the memory. A blind design of memory size can result in dramatic degradation in performance and power efficiency of the entire network. In this study, the authors clarify this impact and show how the optimum value of TCAM capacity is attainable. They also propose a power consumption model for TCAM-based OpenFlow switches. Simulation results show that the proposed solution reduces the average power consumption by 24% compared to the minimum link on method and by 11.5% compared to the minimum node on (MNO) method and thus power efficiency is better achieved when each memory is supplied by appropriate TCAM size.

Performance Analysis of Packet Aggregation Mechanisms and Their Applications in Access (e.g., IoT, 4G/5G), Core, and Data Centre Networks

“…Packet aggregation reduces the number of packets handled by the core routers, but it increases the packet sizes making the energy benefits offered by packet aggregation not intuitive. It has been shown theoretically and practically in [ 53 , 54 , 55 ] that the power consumption of a core router or switch consists of a fixed baseline power and a dynamic power . The baseline power is the power consumed by some components such as the cooling Fans, routing engine cards (e.g., during signalling and updating of the routing tables) and other electronic components when they are idle.…”

“…The dynamic power is the power consumed by the data plane (the line cards and the switching fabric) when it is receiving, processing, and transmitting data packets. Therefore, the power profile of a network router or switch is [ 53 , 54 , 55 , 56 ] …”

“…In order to increase the routing or switching speeds, some core routers and switches contain Ternary Content Addressable Memories (TCAMs) in their hardware which are power-hungry electronic modules, and hence higher energy is required to process a single packet. If the core switches are SDN-based switches, then the power consumption budget considers the power consumed in searching the flow tables, installing the flow rules by the controller, and the communication between the switch and the controller [ 55 ]. Therefore, by aggregating a sufficiently large number of small packets into larger packets, the power consumption of the core routers and switches can be significantly reduced compared to increased energy consumption due to an increase in packet size.…”

Adaptive Flow Timeout Management in Software-Defined Optical Networks

“…Due to the huge amount of traffic occurring in networks and the need to quickly decide where to direct such traffic, high performance of these memories is needed. TCAM allows very fast browsing of the flow entries stored in it, but this is associated with a high production cost and high power consumption [7]. Optimizing the size of the required arrays is an important research problem.…”