pcaplinktype: add the Guidance for Designated Experts section.

This was in the -02 draft; not sure from what source that was generated
and why it wasn't in this file.

draft-ietf-opsawg-pcaplinktype.md

@@ -317,6 +317,34 @@ DLT values are associated with specific operation system captures, and are opera
 |LINKTYPE_ATSC_ALP|289|ATSC Link-Layer Protocol frames, as described in section 5 of the A/330 Link-Layer Protocol specification, found at the ATSC 3.0 standards page , beginning with a Base Header
 
 
+#  Guidance for Designated Experts
+
+When processing a request for a Specification Required allocation the
+Designated Experts are expected to be able to find the relevant
+specification at a clearly stable URL. It is noted that many enterprise
+web sites do not maintain URLs over a long period of time, and a
+documented in a "wp-uploaded" section is highly likely to disappear. In
+addition Specifications that require a reader to click through any kind
+of marketing or legal agreement are not considered public.  (This is the
+opinion of other corporate lawyers, who worry about what their employees
+might have agreed to)
+
+The specification needs to be clearly written, and when the contents of
+the link type can contain and IPv4 or IPv6 header, then the octets
+between the beginning of the link type and the IP header needs to be
+very clearly specified in that document.
+
+Specifications which are not publically available, but which may be
+obtained via liason agreements (such as to ITU-T, 3GPP, IEEE, etc.) are
+acceptable particularly if the document will be public eventually, but
+are discouraged. For other documents, the Designated Expert will need
+use their judgement, or consult the WG or an Area Director.
+
+Linktypes may be allocated for specifications not publically available
+may be made within the First-Come/First-Served area. This includes
+specifications that might be classified. The minimal requirement is for
+a contact person for that link type.
+
 #  Contributors
 
 Insert pcap developers etc. here