Information element

An information element, sometimes informally referred to as a field, is an item in Q.931[http://www.itu.int/rec/T-REC-Q.931/en/ ITU-T Recommendation Q.931] Digital subscriber Signalling System No. 1: ISDN user-network interface layer 3 specification for basic call control and Q.2931[http://www.itu.int/rec/T-REC-Q.2931/en ITU-T Recommendation Q.2931] Digital Subscriber Signalling System No. 2 – User-Network Interface (UNI) layer 3 specification for basic call/connection control messages, IEEE 802.11 management frames,{{cite book |publisher=IEEE-SA |title=IEEE 802.11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications |date=14 December 2016 |doi=10.1109/IEEESTD.2016.7786995 | version=(2016 revision)|isbn=978-1-5044-3645-8 }} and cellular network messages sent between a base transceiver station and a mobile phone or similar piece of user equipment.[http://www.etsi.org/deliver/etsi_ts/124000_124099/124007/13.00.00_60/ts_124007v130000p.pdf 3GPP Technical Specification 24.007 as published by ETSI], Section 11.2.1 An information element is often a type–length–value item, containing 1) a type (which corresponds to the label of a field), a length indicator, and a value, although any combination of one or more of those parts is possible. A single message may contain multiple information elements.

The abbreviation IE is found in many technical specification documents from 3GPP. It is not uncommon for a single specification document to contain thousands of references to IEs.