Qtech QSW-3900-48-SFP-DC [67/245] Port based and 802 q vlan

Qtech QSW-3900-48-SFP-DC [67/245] Port based and 802 q vlan
QTECH Software Configuration Manual
5-66
5.1.5 Port-Based and 802.1Q VLAN
This is the simplest yet the most effective way of classifying VLANs. It groups VLAN members by port.
After added to a VLAN, a port can forward the packets of the VLAN.
5.1.6 Port link type
Based on the tag handling mode, a ports link type can be one of the following three :
· Trunk port : the port can belong to multiple VLANs, can receive/send packets for multiple VLANs,
normally used to connect network devices;
The differences between Access and Trunk port :
· A Access port allows packets of multiple VLANs to be sent with or without the Tag label;
· A Trunk port only allows packets with Tag label.
5.1.7 Default VLAN
You can configure the default VLAN for a port. By default, VLAN 1 is the default VLAN for all ports.
However, this can be changed as needed.
· Ports PVID only belongs to one tag of VLAN. Therefore, its default VLAN is the VLAN it resides in and
cannot be configured.
· You can configure the default VLAN for the Trunk port or the Access port as they can both belong to
multiple VLANs.
5.1.8 Super VLAN
With the development of networks, network address resource has become more and more scarce. The
concept of Super VLAN was introduced to save the IP address space. Super VLAN is also named as VLAN
aggregation. A super VLAN involves multiple sub-VLANs. It has a VLAN interface with an IP address, but no
physical ports can be added to the super VLAN. A sub-VLAN can has physical ports added but has no IP address and
VLAN interface. All ports of sub-VLANs use the VLAN interfaces IP address of the super VLAN. Packets cannot be
forwarded between sub-VLANs at Layer 2.
If Layer 3 communication is needed from a sub-VLAN, it will use the IP address of the super VLAN as the
gateway IP address. Thus, multiple sub-VLANs share the same gateway address and thereby save IP address
resource.
The local Address Resolution Protocol (ARP) proxy function is used to realize Layer 3 communications
between sub-VLANs and between sub-VLANs and other networks. It works as follows : after creating the super
VLAN and the VLAN interface, enable the local ARP proxy function to forward ARP response and request packets.
5.1.9 VLAN interface type
System supports IEEE 802.1Q which possesses two types of VLAN interfaces. One is tagged, and the other
is untagged.
Tagged interface can ad VLAN ID, priority and other VLAN information to the head of the packet which is
out of the interface. If the packet has included IEEE 802.1Q information when entering the switch, the mark
information will not be changed; if the packet has not includes IEEE 802.1Q mark information, system will
determine the VLAN it belongs to according to the default VLAN ID of the receiving interface. Network devices
supported IEEE 802.1Q will determine whether or not to transmit this packet by the VLAN information in the mark.
Untagged interface can drop the mark information from all the packets which are out of the interface. When
a frame is out of a untagged interface, it will not contain IEEE 802.1Q mark information. The function of dropping
the mark makes the packet can be transferred from the network device supported mark to the one which doesnt

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