Mine Site Technologies NS40 I.S., User Manual, Page: 30 / 98

3.1 Understanding Trunk and Access Ports
When VLANs are enabled, network switch ports are assigned to be either trunk ports or access ports.
These two types of port allocations determine how data is transmitted and relayed.
3.1.1 Trunk Ports
Trunk ports provide a connection for multiple VLANs between network devices and access points. They
will only transmit frames (packets of data) that belong to the assigned VLANs. To identify the frames, a
network switch will add a tag (known as an 802.1Q tag) to the frame. The tag contains the following
information:
•
VLAN ID
— allows the network switch receiving a frame to identify the VLAN it belongs to for
distribution.
• Priority ID — allows the network switch to prioritise distribution when multiple frames are being
transmitted. Priority ID ranges from 0-7, where 7 is the highest priority.
When a network switch receives a tagged frame, the tag is read to determine the VLAN it belongs to. If
the switch has devices connected via access ports on the same VLAN, the tag is removed and sent those
devices. If the switch has other trunk ports that have the VLAN as a member, the frame is sent with the
tag intact.
When the network switch receives multiple frames, it will prioritise the distribution of frames based on
the Priority ID in the VLAN ID tag. For more information on creating VLANs, see
Defining VLANs on
page 61.
3.1.2 Access Ports
Access ports connect client devices such as PCs and laptops to the network switch, and can only be
assigned to a single VLAN. Access ports can only send and receive untagged frames belonging to the
assigned VLAN. Any tagged frames sent to an access port will be dropped.
3.1.3 Port Allocation
Any physical ports on the NS40 can be configured to be a trunk port or access port using the web browser
interface. The NS40 default configuration has fibre ports 1-4 allocated as trunk ports as they are usually
connected to other NS40s. For more information on defining ports, see
Configuring Composite Fibre
Ports on page 57.
3.2 VLANs and Wireless Networks
The wireless network switch can have up to four wireless Service Set Identifiers (SSIDs) per WAC. Each
SSID is associated with a single VLAN and functions as an access port on that VLAN.
Revision C 30 NS40 I.S. Wireless Network Switch
Understanding VLANs