Specifically, like in an IPv4 community, BIER can perform around L2 links immediately or in excess of tunnels. Zheng Zhang, Bo Wu, Zhaohui Zhang, IJsbrand Wijnands, Yisong Liu, Hooman Bidgoli, 2022-07-03, This document defines a BIER proxy perform to assistance a one BIER sub-area about multiple underlay routing protocol areas (Autonomous Systems or IGP spots).