10/100 Fast Ethernet Switch User’s Guide
26
Switch Management
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 looks at the network configuration 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 Port 2, the Switch transmits that packet
through Port 2 only, and transmits nothing through Port 1.
♦
Filtering Database.
A Switch filters frames, i.e., does not
relay frames received by a Switch Port to other Ports on