This Recommendation describes the need to allocate network identifiers (known as International Network Identification Codes) for Public Frame Relay Data Networks and ATM Networks numbered under the E.164 numbering plan. The structure of the code is defined. The procedure for the notification to the Telecommunication Standardization Bureau (TSB) of ITU of the assignment of any such International Network Identification Codes for Public Frame Relay Data Networks and ATM Networks numbered under the E.164 numbering plan is also specified. These Network Identification Codes may also be used in Operation and Maintenance procedures for ATM Networks which may be defined for example in Recommendation I.610.