RuggedCom RS1600 Manuel D’Utilisation

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RuggedSwitch
™ User Guide 
VLAN Concepts And Issues 
VLANs and Tags 
A virtual LAN or VLAN is a group of devices on one or more LAN segments that 
communicate as if they were attached to the same physical LAN segment.  VLANs 
are extremely flexible because they are based on logical instead of physical 
connections. 
When VLANs are introduced, all traffic in the network must belong to one or 
another VLAN.  Traffic on one VLAN cannot pass to another, except through an 
intranetwork router or layer 3 switch.   
A VLAN tag is the identification information that is present in frames in order to 
support VLAN operation. 
Tagged vs. Untagged Frames 
Tagged frames are frames with 802.1q (VLAN) tags that specify a valid VLAN 
identifier (VID).  Untagged frames are frames without tags or frames that carry 
802.1p (Prioritization) tags having prioritization information. 
When a switch receives a tagged frame it extracts the VID.  If the VID is not 
allowed on the port the frame was received upon, the frame will be discarded.  If 
the VID is acceptable the frame will be forwarded to other ports in the same 
VLAN. 
Native VLAN 
Each port is assigned a native VLAN number, the Port VLAN ID (PVID).  When 
an untagged frame is received, it is tagged with the native VLAN. 
By default, when the switch transmits a frame on the native VLAN it removes the 
tag before doing so.  The switch can be configured to transmit frames on the 
native VLAN tagged. 
Management VLAN 
Management traffic, like all traffic on the network, must belong to a specific 
VLAN.  RuggedCom switch management is always part of VLAN 1.  This VLAN 
is the native VLAN by default.
 
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