D-Link NetDefend DFL-1660, User Manual

Page: 110 / 595

Disabling an Interface
Should it be desirable to disable an interface so that no traffic can flow through it, this can be done
with the CLI using the command:
gw-world:/> set Interface Ethernet <interface-name> -disable
Where <interface-name> is the interface to be disabled.
To re-enable an interface, the command is:
gw-world:/> set Interface Ethernet <interface-name> -enable
Disabling interfaces can also be done through the Web Interface.
3.4.2. Ethernet Interfaces
The IEEE 802.3 Ethernet standard allows various devices to be attached at arbitrary points or
"ports" to a physical transport mechanism such as a coaxial cable. Using the CSMA/CD protocol,
each Ethernet connected device "listens" to the network and sends data to another connected device
when no other is sending. If 2 devices broadcast simultaneously, algorithms allow them to re-send at
different times.
Note: Usage of the terms "interface" and "port"
The terms Ethernet interface and Ethernet port can be used interchangeably. In this
document, the term Ethernet interface is used throughout so it is not confused with the
port associated with IP communication.
Ethernet Frames
Devices broadcast data as Ethernet frames and other devices "listen" to determine if they are the
intended destination for any of these frames. A frame is a sequence of bits which specify the
originating device plus the destination device plus the data payload along with error checking bits.
A pause between the broadcasting of individual frames allows devices time to process each frame
before the next arrives and this pause is progressively smaller with the faster data transmission
speeds found in normal Ethernet, then Fast Ethernet and finally Gigabit Ethernet.
Physical Ethernet Interfaces
Each logical NetDefendOS Ethernet interface corresponds to a physical Ethernet interface in the
system. The number of interfaces, their link speed and the way the interfaces are realized, is
dependent on the hardware model.
Note: Interface sockets connected via a switch fabric
Some hardware platforms for NetDefendOS use an integrated layer 2 switch for
providing additional physical Ethernet interface sockets. Externally there can be
several separate sockets but these are joined via an internal switch fabric.
Such joined interfaces are seen as a single interface by NetDefendOS and the
NetDefendOS configuration uses a single logical interface name to refer to all of them.
The specifications that relate to different hardware models will indicate where this is
the case.
3.4.2. Ethernet Interfaces Chapter 3. Fundamentals
110