The table which contains Zhone-specific descriptions of each physical line. There is one entry for each physical line in the system and it's primary use is for a user to specify redundant lines in the system. An entry is automatically created by the associated driver whenever a new card is inserted in the system (specifically when an ifindex value is allocated for this port). Statistics, admin state, and operational state can be obtained by the matching ifEntry. This line is part of a redundancy group if the lgRedundancyGroupId is non-zero. This value is a cross-reference to the maching line redundancy group table and must be created by the user. In order for a line/ifEntry to be admin'd active, this line MUST be part of a line redundancy group (even if no redundancy is being configured).