Administrator Guide

1670 Audio Video Bridging
Declarations are “alive” while at least one registration exists. Registrations can
be purged by LeaveTimer if no MVRPDUs with confirmation are received
within the LeaveTimer value after LeaveAll timer expiration, or by receiving
an MSRPDU with the Leave event. The LeaveAll timer is running constantly.
The purging time is variable and depends on when the LeaveAll timer expires
after traffic has been stopped. The possible range is [LeaveTimerValue,
LeaveTimerValue + LeaveAllTimerValue * 1.5].
MMRP
MMRP allows hosts and bridges to dynamically register and de-register
multicast group membership or individual MAC addresses with bridges
attached to the network. MMRP propagates that information across all the
bridges that support Extended Filtering Services in the network. The MAC
address attributes registered, deregistered, and disseminated via MMRP can
apply to a group MAC address or individual MAC addresses. The exchange of
multicast group membership information can result in the creation or
updating of the MAC Address Registration Entries in the Filtering Database
to indicate the ports and VLAN IDs on which the multicast groups have been
registered.
Operationally, MMRP defines a sub-tree of the active spanning tree as a result
of the creation of MAC Address Registration Entries in the filtering databases
of the bridges. End stations may also make use of the group membership
information registered via MMRP to keep track of the groups for which active
members currently exist and the service requirements of upstream devices.
This allows end stations that are sources of frames destined for a Group to
suppress the transmission of such frames if their registered Group
membership and Group service requirement information indicates that there
are no valid recipients of those frames reachable via the networks to which
they are attached.
This end system behavior (known as source pruning) allows MAC service
users transmitting MAC frames destined for a number of groups to avoid
unnecessary flooding of traffic in the local network when there are no group
members registered to receive traffic.