SCALANCE W760/W720 to IEEE 802.11n Web Based Management
Configuration Manual, 11/2014, C79000-G8976-C350-03
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Technical basics
3
3.1
VLAN
Network definition regardless of the spatial location of the nodes
VLAN (Virtual Local Area Network) divides a physical network into several logical networks
that are shielded from each other. Here, devices are grouped together to form logical groups.
Only nodes of the same VLAN can address each other. Since multicast and broadcast
frames are only forwarded within the particular VLAN, they are also known as broadcast
domains.
The particular advantage of VLANs is the reduced network load for the nodes and network
segments of other VLANs.
To identify which packet belongs to which VLAN, the frame is expanded by 4 bytes. This
expansion includes not only the VLAN ID but also priority information.
Options for the VLAN assignment
There are various options for the assignment to VLANs:
●
Port-based VLAN
Each port of a device is assigned a VLAN ID. You configure port-based VLAN in "Layer 2
●
Protocol-based VLAN
Each port of a device is assigned a protocol group.
●
Subnet-based VLAN
The IP address of the device is assigned a VLAN ID.
3.2
MAC-based communication
Adopt MAC automatically / Adopt MAC manually
Frames in the direction from the client to the access point always have the MAC address of
the WLAN interface as the source MAC address. As a result, the "learning table" at the
access point end always has only the MAC address of the WLAN interface of the client. If the
MAC address of a device connected to the client is adopted, both the MAC-based and the
IP-based frames find their destination in precisely this device.
Communication at the MAC address level (ISO/OSI layer 2) can only be to a subscriber
downstream from the client. With IP Mapping, several subscribers downstream from a client
can be addressed based on the IP protocol.