6. IANA Considerations
Label values 0-15 inclusive have special meaning, as specified in
this document, or as further assigned by IANA.
In this document, label values 0-3 are specified in section 2.1.
Label values 4-15 may be assigned by IANA, based on IETF Consensus.
7. Security Considerations
The MPLS encapsulation that is specified herein does not raise any
security issues that are not already present in either the MPLS
architecture [1] or in the architecture of the network layer protocol
contained within the encapsulation.