NJE defines its own type of LU, LUTYPE 0, for all its application-to-application communication in an SNA environment. LUTYPE 0 is a full duplex protocol that is not architected in SNA. Bracket protocol is not necessary since no contention problems exist. Both ends of the SNA session are able to send and receive one or more streams. Compression is mandatory for LUTYPE 0, but compaction is optional. If compaction is desired, each node may specify the compaction table it will use for transmission to the corresponding receiving node. Each table applies for the duration of the session.