Notification » History » Revision 10
Revision 9 (Davide Pesavento, 10/29/2018 06:23 PM) → Revision 10/12 (Davide Pesavento, 06/03/2020 04:55 PM)
# Notification Stream **Notification Stream** is a mechanism of [[Management|NFD Management protocol]]. It is a way to get updates about events happening in the forwarder. This mechanism is useful for monitoring the forwarder's state. ## Naming * A stream of notifications is published under a certain Name prefix. * A notification is a Data packet under this Name prefix with a sequence number. * The sequence number component is a NameComponentWithMarkerAndNumber, as defined in [NDN Naming Conventions (rev 1)](http://named-data.net/doc/tech-memos/naming-conventions.pdf). Conventions](http://named-data.net/doc/tech-memos/naming-conventions.pdf). This component starts with a `0xFE` 0xFE marker, followed by a nonNegativeInteger. * The sequence numbers of notifications in the same stream should be consecutive and increasing. * Each notification is limited to one Data packet. Example: ndn:/localhost/nfd/faces/events/%FE%00 // first notification ndn:/localhost/nfd/faces/events/%FE%01 // second notification ## Notification publisher Notifications from NFD are Data packets generated and signed by NFD. FreshnessPeriod should be set to a minimum value (typically 1 ms) 1ms) to facilitate subscriber operations. The management dispatcher keeps them in an in-memory cache, ready for retrieval by subscribers. ## Notification subscriber The subscriber should initially request the Name of the notification stream with CanBePrefix and MustBeFresh elements. After a notification is received, the subscriber can send an Interest for the next anticipated sequence number, without CanBePrefix and MustBeFresh elements. In both cases, InterestLifetime should be set to a long duration, e.g., 1 minute. If any Interest times out (because no notification is delivered within InterestLifetime), the subscriber should restart with the initial request.