This value indicates which priority, in descending
order, with 0 indicating the lowest priority,
within a group of tunnel instances. A group of
tunnel instances is defined as a set of tunnels
with the same mplsTunnelIndex in this table, but
with a different mplsTunnelInstance. Tunnel group
priorities are used to denote the priority at which
a particular tunnel instance will supercede
another. Instances of tunnels containing the same
mplsTunnelInstancePriority will be used for load
sharing.