Subnet Based Vlans - ZyXEL Communications GS3700 Series User Manual

Table 33 Advanced Application > VLAN > VLAN Port Setting (continued)
LABEL
Acceptable Frame
Type
VLAN Trunking
Isolation
Apply
Cancel

7.5.5 Subnet Based VLANs

Subnet based VLANs allow you to group traffic into logical VLANs based on the source IP subnet you
specify. When a frame is received on a port, the Switch checks if a tag is added already and the IP
subnet it came from. The untagged packets from the same IP subnet are then placed in the same
subnet based VLAN. One advantage of using subnet based VLANs is that priority can be assigned to
traffic from the same IP subnet.
Note: Subnet based VLAN applies to un-tagged packets and is applicable only when you
use IEEE 802.1Q tagged VLAN.
For example, an ISP (Internet Service Provider) may divide different types of services it provides to
customers into different IP subnets. Traffic for voice services is designated for IP subnet
172.16.1.0/24, video for 192.168.1.0/24 and data for 10.1.1.0/24. The Switch can then be
configured to group incoming traffic based on the source IP subnet of incoming frames.
You can then configure a subnet based VLAN with priority 6 and VID of 100 for traffic received from
IP subnet 172.16.1.0/24 (voice services). You can also have a subnet based VLAN with priority 5
and VID of 200 for traffic received from IP subnet 192.168.1.0/24 (video services). Lastly, you can
configure VLAN with priority 3 and VID of 300 for traffic received from IP subnet 10.1.1.0/24 (data
services). All untagged incoming frames will be classified based on their source IP subnet and
prioritized accordingly. That is, video services receive the highest priority and data the lowest.
Chapter 7 VLAN
DESCRIPTION
Specify the type of frames allowed on a port. Choices are All, Tag Only and Untag
Only.
Select All from the drop-down list box to accept all untagged or tagged frames on this
port. This is the default setting.
Select Tag Only to accept only tagged frames on this port. All untagged frames will be
dropped.
Select Untag Only to accept only untagged frames on this port. All tagged frames will
be dropped.
Enable VLAN Trunking on ports connected to other switches or routers (but not ports
directly connected to end users) to allow frames belonging to unknown VLAN groups to
pass through the Switch.
Select this to allows this port to communicate only with the CPU management port and
the ports on which the isolation feature is not enabled.
Click Apply to save your changes to the Switch's run-time memory. The Switch loses
these changes if it is turned off or loses power, so use the Save link on the top
navigation panel to save your changes to the non-volatile memory when you are done
configuring.
Click Cancel to begin configuring this screen afresh.
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