D-Link DES-3624 - Manual (Page 30)

Stackable NWay Ethernet Switch User’s Guide
30 Switch Management Concepts
Topology Change Timer the new root trap is sent out immediately after the Switch’s selection as a new
root.
♦ Topology Change A Topology Change trap is sent by the Switch when any of its configured ports
transitions from the Learning state to the Forwarding state, or from the Forwarding state to the
Blocking state. The trap is not sent if a new root trap is sent for the same transition.
♦ Link Change Event This trap is sent whenever the link of a port changes from link up to link down or
from link down to link up.
♦ Port Partition This trap is sent whenever a port is partitioned as a result of more than sixty-two
collisions on the port (i.e., is automatically partitioned). The number of collisions that triggers this trap
is the same at either 10Mbps or 100Mbps.
♦ Broadcast Storm This trap is sent whenever the port reaches the broadcast storm rising or falling
threshold.
MIBs
Management information and counters are stored in the Switch in the Management Information Base (MIB).
The Switch uses the standard MIB-II Management Information Base module. Consequently, values for MIB
objects can be retrieved from any SNMP-based network manager software. In addition to the standard MIB-
II, the Switch also supports its own proprietary enterprise MIB as an extended Management Information
Base. These MIBs may also be retrieved by specifying the MIB’s Object-Identity (OID) at the network
manager. MIB values can be either read-only or read-write.
Read-only MIBs variables can be either constants that are programmed into the Switch, or variables that
change while the Switch is in operation. Examples of read-only constants are the number of ports and types
of ports. Examples of read-only variables are the statistics counters such as the number of errors that have
occurred, or how many kilobytes of data have been received and forwarded through a port.
Read-write MIBs are variables usually related to user-customized configurations. Examples of these are the
Switch’s IP Address, Spanning Tree Algorithm parameters, and port status.
If you use a third-party vendors’ SNMP software to manage the Switch, a diskette listing the Switch’s
propriety enterprise MIBs can be obtained by request. If your software provides functions to browse or modify
MIBs, you can also get the MIB values and change them (if the MIBs’ attributes permit the write operation).
This process however can be quite involved, since you must know the MIB OIDs and retrieve them one by one.
Packet Forwarding
The Switch learns the network configuration and uses this information to forward packets. This reduces the
traffic congestion on the network, because packets, instead of being transmitted to all segments, are
transmitted to the destination only. Example: if Port 1 receives a packet destined for a station on Port 2, the
Switch transmits that packet through Port 2 only, and transmits nothing through the other ports.
Aging Time
The Aging Time is a parameter that affects the auto-learn process of the Switch in terms of the network
configuration. Dynamic Entries, which make up the auto-learned-node address, are aged out of the address
table according to the Aging Time that you set.