Welcome to the
Green Digital Tool Kit

Cities across Europe are signing the Green Digital Charter which commits them to a wide range of activities towards green digital progress. The three core commitments are: running 5 large scale pilot projects, reducing their ICT carbon footprint by 30% and cooperating with other signatories.

This Toolkit helps interested cities to build on the experiences of others. Find out about sharing activities and tools to improve your green performance. Find out more information here.

Featured Activity


City: TestCity
Activity Type:  Operational Exchange
Application Area:  Energy
Role of ICT:  Efficiency

Test for CoM

Featured Tool

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City: Linköping  |  Tool type: Software

ICT energy usage measurement process

INTRODUCTION The EasyARP application is a tool for measuring the uptime of IP based ICT equipment. EasyARP has been developed by the City of Linköping to be used when running NiCE project ICT Footprint Tool, and it is free for anyone to use. HOW IT WORKS EasyARP is run as a service on a server and is configured through a client. It is designed to be run in batches of typically 24 hours (time is configurable). When running a batch it uses the SNMP protocol to read the ARP table from a specified switch, once every 30 minutes. The result is stored in an internal database (MS Access format). At the end of each batch EasyArp resolves all the collected IP addresses through the DNS and creates an output text file. The text file includes the IP address, the MAC address, the DNS name and a counter which is the number of times that each equipment has been identified (during the batch). The text file is then manually imported and analyzed in a spreadsheet program. By using the DNS names it is possible to group equipment into different categories (computers, printers, servers and so on) and the counter tells us how many hours each equipment has been switched on during the batch. All IP-based equipment can be monitored in this way but it is not possible to distinguish between different models of equipment that share the same naming convention. Equipment that changes IP addresses during the batch, i.e. portable computers that are moved from one network segment to another, will only be registered with the latest IP address used. The summarized value for this kind of equipment will therefore usually be a little bit lower and not be 100 % accurate. It is also necessary to know of equipment that is in sleep mode, updates the ARP table or not. If they do it has to be taken into account when running the analysis. Since EasyARP doesn’t utilize traditional probing with PING to every unit, EasyArp does not inflict any performance issues on the network and has no delays. To use EasyARP in a proper manner a few pre-conditions has to be fulfilled: • There must be a core network switch that holds an ARP table for the entire network. Otherwise only parts of the network can be measured at a time • The internal update frequency of the ARP table must be shorter than 30 minutes in the network switch • There must be a standardized way of naming ICT equipment (in DNS). Otherwise it will be hard to group and identify categories of ICT equipment like computers, printers, servers and so on.