ZyXEL Communications Plumbing Product metrogigabit switch User Manual

Chapter 9 VLAN

MGS3700-12C User’s Guide

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.

For example, an ISP (Internet Services 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.    

Ingress Check 

If this check box is selected for a port, the Switch discards incoming 
frames for VLANs that do not include this port in its member set.

Clear this check box to disable ingress filtering. 

PVID

A PVID (Port VLAN ID) is a tag that adds to incoming untagged frames 
received on a port so that the frames are forwarded to the VLAN group 
that the tag defines.

Enter a number between 1and 4094 as the port VLAN ID.

GVRP

Select this check box to allow GVRP on this port. 

Acceptable 
Frame Type 

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.

VLAN Trunking

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.

Isolation

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.

Apply

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.

Cancel

Click Cancel to begin configuring this screen afresh. 

Table 18   Advanced Application > VLAN > VLAN Port Setting  (continued)