PrefixAnnouncement » History » Revision 11
Revision 10 (Junxiao Shi, 08/19/2023 01:58 AM) → Revision 11/14 (Davide Pesavento, 12/16/2024 08:40 PM)
# Prefix Announcement Protocol The **prefix announcement protocol** allows registering prefixes using a *prefix announcement object*. It is an alternative to NFD [[RibMgmt|RIB Management protocol]]'s `rib/register` verb. As of November 2024, 2023-Aug, this protocol is only implemented in YaNFD; it is not yet implemented in NFD. ## Prefix Announcement Object 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](https://named-data.net/publications/techreports/ndn-tr-22-ndn-memo-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. **Validity period** of a prefix announcement object is given in 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/%FD%01/%00%00 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). ## Command Verb: 'announce' This command announces a prefix using a prefix announcement object. NFD-RIB accepts this command as a *signed Interest* with the following name: ``` /localhost/nfd/rib/announce/<params-sha256> /localhop/nfd/rib/announce/<params-sha256> ``` The Interest's ApplicationParameters element carries the prefix announcement object. NFD-RIB converts this command into an equivalent `rib/register` command. The route's *origin* is set to "prefix announcement" (=129). The response is the same as the `rib/register` command. Note: There is no 'unannounce' command. Instead, use `rib/unregister` command. ### Example ``` Interest Name /localhop/nfd/rib/announce/params-sha256=607a2bc7653eea18b47e92b84edc58bab5aaa321d4efb39ceeccc6cafbcbb3d1 MustBeFresh ApplicationParameters PrefixAnnouncement InterestSignatureInfo InterestSignatureValue ``` Assuming the enclosed PrefixAnnouncement is the one shown in the previous example, NFD-RIB should interpret this command same as `rib/register` command with the following ControlParameters: * Name: `/net/example` * Origin: 129 * ExpirationPeriod: 3600000; optionally, constrained by the ValidityPeriod of the PrefixAnnouncement