Abstract
This article is addressed to network engineers and managers of large enterprises that are interested in energy consumption of network devices. In the last years many efforts in telecommunications network research and design have been devoted to reduce energy consumption of network devices. Development of green routers aimed at saving energy when the input traffic is low is receiving increasing attention in the scientific community. In this article we face the problem of further reducing power consumption in transport networks adopting the Fast Reroute technique together with a low power idle approach, which result in substantial energy saving when the traffic on the network is low. We have run simulations using NS-2 and as test case, we developed the proposed approach on top of the NetFPGA architecture and results are very promising for larger exploitation.
Top1. Introduction
Today, the load of networks typically exceeds their long-term utilization by a wide margin (Reforgiato, 2013). Moreover, as shown in (Barford, 2010), current network nodes have a power consumption that does not depend on the actual traffic load they face. This implies an energy waste in today networks (Ipmon Sprint, 2007; Jardosh, 2007). The increasingly cost of energy led to a general concern about this occurrence. Today, in fact, 37% of the total ICT emissions are due to telecommunications companies infrastructures and devices. For this reason, addressing energy efficiency challenges in wireline networks is receiving considerable attention in the literature (Barford, 2008; Gupta, 2003; Mahadevan, 2009; Nedevschi, 2008). Moreover a number of research projects has been started on this topic (see for example Earth (2010), Chron (2010), Greentouch (2011), C2power (2010)). Some novel hardware devices that allow entering different energy power states are therefore expected in the near future (Cisco, 2009). Routers are device that forwards data packets between computer networks, creating an overlay Internetwork. Cisco (Cisco, 2009), the pioneer in home networking, has sold more than 70 million Linksys routers worldwide and is leading the charge in the next-generation connected home. A routing protocol specifies how routers communicate with each other, disseminating information that enables them to select routes between any two nodes on a computer network. Routers are therefore one of the core elements of computer networks. Moreover, Multiprotocol Label Switching (MPLS) is a mechanism in high-performance telecommunications networks that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table.
Key Terms in this Chapter
Quality of Service (QoS): the overall performance of a computer network. Several related aspects of the network service are error rates, bandwidth, throughput, transmission delay, availability, jitter.
Green Router: A green router has software/hardware capabilities that reduce its power consumption while maintaining the same Quality of Service.
Multiprotocol Label Switching (MPLS): a mechanism in high-performance telecommunications networks that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table.
Djikstra’s Algorithm: a graph search algorithm often used in routing that solves the shortest path problem for a graph with certain edge path costs.
Router: a device that forwards data divided in packets among different networks.
Low Power Idle (LPI): a signal that puts to sleep the transmit chips in a system.
Routing Protocol: indicates how routers can communicate with each other, forwarding data by selecting routes between nodes on a computer network.
NetFPGA: an open source hardware and software for rapid prototyping of computer network devices.