This data type is used as the syntax of the ifType
object in the (updated) definition of MIB-II's
ifTable.
The definition of this textual convention with the
addition of newly assigned values is published
periodically by the IANA, in either the Assigned
Numbers RFC, or some derivative of it specific to
Internet Network Management number assignments. (The
latest arrangements can be obtained by contacting the
IANA.)
Requests for new values should be made to IANA via
email (iana@iana.org).
The relationship between the assignment of ifType
values and of OIDs to particular media-specific MIBs
is solely the purview of IANA and is subject to change
without notice. Quite often, a media-specific MIB's
OID-subtree assignment within MIB-II's 'transmission'
subtree will be the same as its ifType value.
However, in some circumstances this will not be the
case, and implementors must not pre-assume any
specific relationship between ifType values and
transmission subtree OIDs.
IANAtunnelType
enumeration
The encapsulation method used by a tunnel. The value
direct indicates that a packet is encapsulated
directly within a normal IP header, with no
intermediate header, and unicast to the remote tunnel
endpoint (e.g., an RFC 2003 IP-in-IP tunnel, or an RFC
1933 IPv6-in-IPv4 tunnel). The value minimal indicates
that a Minimal Forwarding Header (RFC 2004) is
inserted between the outer header and the payload
packet. The value UDP indicates that the payload
packet is encapsulated within a normal UDP packet
(e.g., RFC 1234).
The values sixToFour, sixOverFour, and isatap
indicates that an IPv6 packet is encapsulated directly
within an IPv4 header, with no intermediate header,
and unicast to the destination determined by the 6to4,
6over4, or ISATAP protocol.
The remaining protocol-specific values indicate that a
header of the protocol of that name is inserted
between the outer header and the payload header.
The assignment policy for IANAtunnelType values is
identical to the policy for assigning IANAifType
values.