The Switch Database (Sdb) - 3Com MSH 1005 User Manual

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HAPTER WITCH ONFIGURATION

The Switch Database (SDB)

The Switch 1005 maintains a database of all addresses received on all
of its local ports. It uses the information in this database to decide
whether a frame should be forwarded or filtered. The database holds
up to a maximum of 500 entries, each entry consists of the MAC
address of the device and an identifier for the port on which it was
received.
If you have set up Traps for the Switch 1005, notification that the
database is becoming full is provided by two traps:
Database is 90% full
Database is 100% full
These traps indicate that the maximum number of devices which can
be attached to the Switch 1005 has been reached. You cannot connect
any more devices to the Switch 1005, however, additional devices can
be connected to the rest of the network infrastructure.
Entries are added into the SDB in two ways:
The module can learn entries, that is, the unit updates the SDB with the
source MAC address and the port identifier on which the source MAC
address is seen.
The system administrator can enter and update entries using a MIB
browser, an SNMP Network Manager, or the Switch Database screen
described over the following pages.
There are two types of entries in the SDB:
Ageing entries — Initially, all entries in the database are of type
Ageing. Entries in the database are removed (aged) if, after a period of
time (ageing time), the device has not transmitted. This prevents the
database from becoming full with obsolete entries by ensuring that
when a device is removed from the network, its entry is deleted from
the database. Ageing entries are deleted from the database if the
Switch 1005 is reset or a power off/on cycle occurs. For more
information about setting an ageing time, see "Switch 1005 Setup" on
page 3-4.
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