C–2
Management Details
If for some reason you do not want a specific DECbridge 90 unit to be the
designated hub manager, you can disable the hub management features
with the command DEFINE BRIDGE HUB_MANAGEMENT DISABLE.
After the DECbridge 90 has become the designated hub manager, you
can use SET or SHOW REPEATER and SET or SHOW PORT commands
without restriction. There is, however, an additional delay before the
SHOW ADDRESS command provides complete information.
DEFINE commands do not take effect until the next SET ALL or RESET
of the DECbridge 90. To have the command take effect immediately, you
must also issue the corresponding SET command.
Annotating the Bridge Address Table
The DECbridge 90 SHOW ADDRESS command lists the DECrepeater
slot number and port number for every station in the work group
that is connected to the same DEChub by a DECrepeater. However,
when changes are made to the network topology, it takes time for that
information to appear in the DECbridge 90 address table. The algorithm
for creating this information proceeds as follows:
For every station in the work group
•
Tell the repeaters to wait for a message from this station.
•
Wait up to 90 seconds for the station to transmit a message.
•
Ask the repeaters what port it came from.
If a station does not transmit a message within 90 seconds, the
algorithm proceeds to the next station. In a typical network situation,
this process is completed in a few minutes. After a bridge is newly
installed or reset, you can expect this information to be complete after
about 10 minutes of operation.
If some stations do not often transmit messages, the DECbridge may
hang on those stations for up to 90 seconds each before moving on. If you
add a station, or move it to another port, you can expect it to take about
10 minutes before a SHOW ADDRESS command recognizes this move.
If you remove a station from the network entirely, it will take a full
address age time (default is 30 minutes) for the DECbridge 90 to notice.
If you remove many stations at once, the DECbridge 90 hangs on each
of these stations for 90 seconds, until they age out of the bridge address
database. In this case, it will usually take the full address age time (30
minutes) before the port number annotations are complete.