Equitel N968, User Manual

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September 2011 Ed.2.0
EQUITEL – Technical Manual N968
81
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802.1Q VLAN
When the VLAN operation mode is set on 802.1Q, all ports on the switch belong to the
default VLAN of VID 1, which means they logically are regarded as members of the
same broadcast domain. The valid VLAN ID is in the range of number between 1 and
4094. The amount of VLAN groups is up to 256 including the default VLAN that cannot
be deleted.
GVRP (GARP VLAN Registration Protocol) is a protocol that facilitates control of
VLANs within a larger network. GVRP conforms to the IEEE 802.1Q specification,
which defines a method of tagging frames with VLAN configuration data. This allows
network devices to dynamically exchange VLAN configuration information with other
devices. For example, with GVRP enabled, the switches are able to automatically
exchange the information of their VLAN database. Therefore, the user needn’t
manually configure the link type. The packets belonging to the same VLAN can
communicate across switches.
Each member port of 802.1Q is on either an Access Link (VLAN-tagged) or a Trunk
Link (no VLAN-tagged). All frames on an Access Link carry no VLAN identification.
Conversely, all frames on a Trunk Link are VLAN-tagged. Besides, there is the third
mode—Hybrid. A Hybrid Link can carry both VLAN-tagged frames and untagged
frames. A single port is supposed to belong to a particular VLAN group, except it is on
a Trunk/Hybrid Link.
The technique of 802.1Q tagging inserts a 4-byte tag, including VLAN ID of the
destination port—PVID, in the frame. With the combination of Access/Trunk/Hybrid
Links, the communication across switches also can make the packet sent through
tagged and untagged ports.