IEC 61850-8-1:2011 specifies a method of exchanging time-critical and non-time-critical data through local-area networks by mapping ACSI to MMS and ISO/IEC 8802-3 frames. Defines a standardized method of using the ISO 9506 services to implement the exchange of data. For those ACSI services defined in IEC 61850-7-2 that are not mapped to MMS, this part defines additional protocols. It describes real utility devices with respect to their external visible data and behaviour using an object oriented approach. The objects are abstract in nature and may be used to a wide variety of applications. The use of this mapping goes far beyond the application in the utility communications. The main changes with respect to the previous edition are listed below: - the support of gigabit Ethernet, - the link layer redundancy, - the extension of the length of the object reference, - the extension of the reason for inclusion type for comprehensive logging, - the mapping of the tracking services, - a second mapping of the objectReference when used in the tracking services, or as linking, - the extension of the AdditionalCause enumeration, - the simulation of GOOSE telegram, - the so-called fixed-length encoded GOOSE, - the removal of the SCL Control Block.