Enterasys Networks 6000 - Manual (Page 89)

The Device View
2-70 Managing the Module
802.1Q VLANs
This section introduces and describes pre-standard IEEE 802.1Q port-based Virtual Local
Area Network (VLAN) technology and the windows used to configure Enterasys 802.1Q
VLAN-capable devices.
SmartSwitch 6000 or Matrix E7 firmware version 4.00.08 and above support the
pre-standard IEEE 802.1Q draft specification for port-based VLANs.
What is a VLAN?
A Virtual Local Area Network (VLAN) is a logical group of devices that function as a
single Local Area Network segment (broadcast domain). Devices comprising a VLAN
may be (physically) widely separated, allowing users located in separate areas or
connected to separate ports to belong to a single VLAN group. Users assigned to a VLAN
can send and receive broadcast and multicast traffic as though they were all physically
connected to a single network segment. VLAN-capable switches isolate broadcast and
multicast traffic received from VLAN groups, and contain broadcasts and multicasts from
members of a VLAN within that group.
What is an 802.1Q Port-Based VLAN?
Switches that support the pre-standard IEEE 802.1Q draft specification for port-based
VLANs act by classifying frames into VLAN membership. Usually, VLAN classification
is based on tag headers (VLAN tags) in the headers of data frames. The tag header is
inserted into the frame directly after the Source MAC address field. A four-byte field in
the tag header is used as the VLAN identifier. These VLAN tags are added to data frames
by the switch as the frames are transmitted and/or received by certain ports, and are later
used to make forwarding decisions by the switch and other 802.1Q switches. In the
absence of a VLAN tag, a frame is assigned VLAN membership according to the VLAN
configuration of the switch port that receives the frame.
About 802.1Q VLAN Configuration and Operation
An 802.1Q VLAN is defined by assigning it a unique identification number (the VLAN
ID) and an optional name. The VLAN ID is used to identify data frames that originate
from, and are intended for, the ports assigned to the VLAN. Up to 64 VLANs may be
created, with VLAN IDs ranging from 2-4094. VLAN ID 1 is reserved for the Default
VLAN.
NOTES
In certain SmartSwitch 6000 firmware versions, 802.1Q operation is not fully
supported.Refer to your firmware release notes for more information.