Packet Forwarding - D-Link DES-3250TG User Manual

DES-3250TG Layer 2 Fast Ethernet Switch User's Guide
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 port and type 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 enters the relationship between destination MAC
addresses and the Ethernet port the destination resides on into
its forwarding table. This information is then used to forward
packets. This reduces broadcast storms on the network,
because packets, instead of being transmitted to all ports, are
transmitted to the destination port only. Example: if Port 1
26