Note: An alternate site for UDLR's files is: http://www.udcast.com/udlr The UDLR working group issued the RFC 3077 in March 2001. This RFC describes a link-layer tunneling mechanism (LLTM) for supporting unidirectional links (UDL) in the Internet. During the design of this mechanism by the UDLR working group, several implementations evolved. These implementations are fully interoperable and are currently being used in several operational environments. As of the publication of RFC 3077, the working group has decided to further their work by issuing the following objectives: 1. Produce informational rfc's that describe in detail the requirements of example case study scenarios as listed below. Note that these scenarios relate to field experiments that are being undertaken based on the LLTM mechanism: a) configuration of multicast routing protocols over a unidirectional link b) configuration of unicast routing protocols over a unidirectional link c) securing operation of a UDLR network 2. Identify security holes 3. Push the current document (RFC 3077) status to Draft Standard.