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demand priority (DP)

Demand Priority (DP) is used as an access method for100Base-VG. The Demand Priority method is a polling mode in which a repeater polls the individual end devices for transmission requests.

In the demand-priority method, each end device signals its transmission request to the repeater with a priority identifier (low or high). The distribution of the transmission rights takes place within the priority classes according to a round-robin procedure. Since the allocation of the transmission rights lies with the repeater, it can provide a guaranteed transmission bandwidth for time-critical applications such as interactive video/audio applications. This means that the transmission medium can be utilized up to almost 100%.

The repeater can be cascaded so that larger networks can be set up. The repeater has two operating modes: Privacy Mode and Promiscuous Mode. In Privacy Mode, the data packets are only sent to the addressee; this operating mode is used by the terminal devices, so that only the data packets for the respective receiver arrive at a terminal device port. In Promiscuous Mode, on the other hand, the data packets are sent to all; this operating mode is used between the repeaters, as well as for bridges and protocol analyzers.

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Englisch: demand priority - DP
Updated at: 14.02.2019
#Words: 336
Translations: DE