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Cooper Bussmann 945U-E Wireless Ethernet Modem & Device Server User Manual
63
Rev Version 2.14
For the DNS server configuration to be effective, each DNS client must be configured with the address of this
DNS server, as either the primary or secondary DNS (secondary DNS is only used if there is no response from
the primary DNS). Normally this is done by setting the primary DNS field of the DHCP server configuration to the
wireless IP address. This address is then provided to client units to use as their primary DNS server address when
the DHCP server issues an IP address. The DNS server is configured using the following settings.
Enabled
Select this checkbox to enable the DNS server.
Domain Name
This is a common suffix applied to the name of each device in the network. If your
network is part of a larger network, this would be assigned to you by the relevant
naming authority. If your network is stand-alone, this field is set to an arbitrary name
of your choice.
Device Name (Host
Name)
This is the DNS name of the local device (commonly referred to as the host name
or computer name). This setting is duplicated on the main Module Information
configuration page. This is the name that is used to refer to this device (see “3.23
Module Information Configuration”).
3.22 VLAN
What is VLAN
VLAN (virtual local area network) is a way of splitting a network into groups that could extend beyond a single
traditional LAN to groups of LANs, each identified with a different VLAN ID (VID). Using a VLAN, you can group
users by logical connections instead of physical location. This can increase security and help improve the efficiency
of traffic flow by limiting multicast and broadcast messages. Traffic between VLANs is blocked unless the VLAN is
identified with the correct VLAN ID.
There are three main VLAN modes that the 945U-E supports:
•
VLAN (Pass-through Mode)
—A transparent bridge in which frames are forwarded unmodified. This is the
default mode of the modem in which all frames pass transparently through the bridge regardless of whether
they are VLAN tagged or untagged. This is the most common VLAN mode and requires no VLAN configuration
at all. In VLAN Pass-through mode, access to the internal management functions is via untagged frames only,
using the IP address and subnet mask configured on the Network page.
•
VLAN Aware (Bridging Mode)
—A VLAN bridge that allows only explicitly configured VLANs that correspond to
the configured VLAN groups to pass data. VLAN Bridging mode is used when the tagging method is changed
in a bridged network, for example, if a frame traverses from a VLAN group to an interface that is not configured
in a VLAN. When a VLAN packet is passed to an untagged VLAN interface, the tag is removed so that the
packet can properly enter the network. Similarly, if an untagged VLAN packet is passed to a VLAN group a
VLAN tag is added. When one or more VLAN groups have been configured, VLAN Pass-through is disabled
and VLAN Aware mode is enabled.
•
VLAN Aware (Routing Mode)
—Same as “VLAN Aware (Bridging Mode)” above, except that the VLANs are
routed, not bridged. When a packet is routed from one VLAN to another on a different interface. The interfaces
can be tagged or untagged, and are generally on different subnets.
Enabling VLANs will allow the module to facilitate a number of possible VLAN topologies, such as:
• Segregating a wireless network into multiple virtual networks.
• Functioning as the wireless backbone on a VLAN trunk.
• Enabling a wireless network or part of the wireless network to form a VLAN trunk.
• Defining multiple virtual networks, each with a different priority to define traffic class based forwarding behavior
over the radio channel.
Each module can be set up to accept different networks by configuring VLAN groups and having the interfaces
(such as Ethernet, wireless, or WDS repeater) configured to accept or reject tagged or untagged communications
frames.
