This attribute indicates the security level of the trunk. Zero(0)
represents the most secure trunk and seven(7) represents the least
secure. The path's minimum security requirement is indicated by
the Plc requiredSecurity attribute, with values identical in range and
meaning to this attribute. PORS ensures that the route selected does
not contain a trunk whose PathAdmin trunkSecurity attribute is
numerically greater than the path's requiredSecurity.