Prefix Announcement Object¶

The prefix announcement object is a Data packet that represents an application's intent of registering a prefix toward itself. A Data packet that satisfies the following requirements is a prefix announcement object:

• Name starts with the announced prefix, followed by a fixed 32=PA keyword name component, followed by a version component and a segment component as defined by the NDN Naming Conventions. In the current revision of this specification, the segment number MUST be zero.
• ContentType MUST be 5 (prefix announcement).
• Content contains a sequence of TLV elements, including at least an ExpirationPeriod element. Ordering of these TLV elements is insignificant. Unrecognized non-critical TLV elements are permitted and MUST be ignored.

The validity period of a prefix announcement object is given in the ExpirationPeriod and ValidityPeriod elements in its Content.

• ExpirationPeriod gives the duration for which the prefix announcement remains valid. The duration begins when a node or program receives the prefix announcement. This element is required.
• ValidityPeriod gives the absolute time range in which the prefix announcement remains valid. It is ignored if the receiving node does not have a UnixTime clock. This element is optional.
• When both ExpirationPeriod and ValidityPeriod are present, the most restrictive constraint applies.

The trust model of a prefix announcement is to be defined by the application.

Example¶

Data
  Name /net/example/32=PA/v=0/seg=0
  MetaInfo
    ContentType 5 (prefix announcement)
  Content
    ExpirationPeriod 3600000
    ValidityPeriod
      NotBefore 20181030T000000
      NotAfter  20181124T235959
  SignatureInfo
  SignatureValue 

This prefix announcement object announces the prefix /net/example. It is valid for one hour from its receipt, between the dates 2018-10-30 and 2018-11-24 (included).