3com TR User Manual

The Switch 2000 TR supports a database of transpar-
ent addresses received on its local ports. Using this 
information, the Switch 2000 TR determines whether 
a transparent frame should be forwarded or filtered. 
The database holds a maximum of 2000 entries, each 
of which includes the MAC address and an identifier 
for the port on which it was received.

The Switch 2000 TR Unit Database View allows you 
to set up, maintain, and view the Switch 2000 TR 
database.

SNMP Traps report the database status as follows:

■

Database 90% full 

■

Database 100% full

These traps indicate that the maximum number of users 
has been or is about to be met. When the maximum 
number has been met, you cannot add any more users to 
the database until some are removed. This limitation does 
not apply to users connected to the remainder of the net-
work.

The Switch 2000 TR database has two types of 
entries:

■

Aging Entries—Initially, all entries in the database 
are the aging type. As traffic moves through the 
Switch 2000 TR, device addresses are learned and 
stored. Entries are removed (aged out) if the device 
has not transmitted any packets for a set period of 

time (aging time). This practice prevents the data-
base from filling with obsolete entries. When a 
device is removed from the network, its entry is 
deleted from the database. Using an SNMP-based 
management application or the VT100 console 
(serial port or Telnet session), you can set the aging 
time (set in seconds) with a default of 5 minutes. 
Aging entries are deleted if the Switch 2000 TR is 
reset or turned off.

■

Permanent Entries—Permanent entries are 
retained in the database even when the Switch 
2000 TR is reset or powered down. Addresses are 
made permanent by a system administrator via a 
network manager application and the switch data-
base. Refer to “Switch Database Configuration” 
for more information.

Entries to the database happen in two ways:

■

The Switch 2000 TR can learn up to 2000 
addresses. Addresses include the source MAC 
address and the port identifier of the port on 
which the source MAC address is seen. Addresses 
are not learned on the designated downlink. 

■

The system administrator can enter and update 
entries using an SNMP MIB browser, a network 
manager application, or the Switch 2000 TR data-
base screen. Refer to “Switch Database Configura-
tion” for more information.