This table is used in order to manage auto bandwidth data.
This table is sparse dependent on the mplsTunnelTable. An entry
in this table exists for each mplsTunnelEntry with a
mplsTunnelRole of 'head' or 'headTail'. Each row contains
auto-bandwidth data for the tunnel identified by the indexes
defined later.
An entry is created as soon as a 'head' or 'headTail' MPLS TE
tunnel is configured in the system.