Users Guide

1682 Audio Video Bridging
MSRP
MSRP provides a mechanism for the reservation of resources for specific
traffic streams traversing a bridged network.
MSRP categorizes AVB devices into talkers (stream sources) and listeners
(stream destinations). An AVB device may be both a talker and a listener.
MSRP operates via several types of announcements (MRP declarations). The
announcements are propagated throughout the AVB network.
Announcements may occur in any order except when noted otherwise.
Listeners announce that they wish to receive a stream by sending an asking
declaration. The AV bridges and talkers register this declaration.
Talkers announce that they are able to supply a stream with certain
characteristics by sending an offering declaration. This declaration includes
the ranking of the reservation's importance, its bandwidth, Ethernet priority
level, and destination MAC address. Optionally, a higher-layer stream ID is
also included. If a bridge has sufficient resources to propagate the stream, it
forwards the declaration. If a bridge has insufficient resources to supply the
stream, it converts the declaration into a failed declaration. In addition, the
bridge converts the asking declaration into an asking failed declaration and
forwards that declaration to the talker.
Listeners announce that they have configured their queues for handling a
stream and that transmission can begin by sending a ready declaration. Only
if a bridge has registered both the offering and the ready declarations will it
configure its output queues on the port from which the ready declaration was
received and propagate the ready declaration.
When a ready declaration is registered by the talker, it will start sending the
data stream.
Regardless of the order in which the registrations occur, it is the presence of
both the offering registration on an input port and the ready registration on
an output port that triggers the bridge to configure the output port and allow
propagation of the AVB stream from the talker.