Bus Reset (Long, Short) - Yamaha mLAN Manual Book

3. Bus Reset (Long, Short)

When a cable is connected or disconnected within a network, or when the power of a node is
turned on or off, the bus* will be initialized and the network will be reconfigured. There are two
types of bus reset: long bus reset and short bus reset.
* "Bus" is a technical term indicating a system by which multiple electronic devices
share a single communication route to transfer data. IEEE 1394 is a "bus" specifica-
tion. In the document, the term "bus" refers to the portion that is operating according
to IEEE 1394.
Long bus reset
This will occur when the topology has been changed or broken without leaving the previous root,
or if the power of the root node has been turned off. This will also occur if a device that does not
support short bus reset (such as an IEEE 1394-1995 compatible DV camcorder) is connected.
Since a certain amount of time is required for reconfiguration, audio data etc. will be interrupted.
After the bus has been initialized, the following processes are performed:
• The parent/child relationships between each node are determined, and after the root node has
been decided, self-identifying packets (basic data) for each node will be transmitted. This is
called "tree identification.")
• The root node will be assigned as the cycle master.
Short bus reset
This will occur if the change in topology does not involve the root, and since it requires less time
than the long bus reset, audio data etc. will not be interrupted. This will occur when a leaf node is
added or removed, or if the power of a leaf node is turned on or off.
mLAN feature
In the case of mLAN devices, the cable port LED will light green to indicate cable ports connected as leaf
nodes.
Root
Removing cables
: Long bus reset
: Short bus reset
Technical Explanations
Root
Turning the power off
: Long bus reset
No mark : Short bus reset
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