Allied Telesis Rapier Switch - Manual (Page 45)

Layer 2 Switching 45
Software Release 2.5.1
C613-02025-00 REV B
4. A port cannot be untagged and tagged for the same VLAN.
5. The mirror port, if there is one, is not a member of any VLAN.
Protected VLANs
If a VLAN is Protected, Layer 2 traffic between ports that are members of a
Protected VLAN is blocked. Traffic can be Layer 3 switched to another VLAN.
This feature prevents members of a Protected VLAN from communicating with
each other yet still allows members to access another network. Layer 3 Routing
between Ports in a Protected VLAN can be prevented by adding a Layer 3
filter. The Protected VLAN feature also allows all of the members of the
Protected VLAN to be in the same subnet.
A typical application is a hotel installation where each room has a port that can
be used to access the Internet. In this situation it is undesirable to allow
communication between rooms.
To create a Protected VLAN, use the command:
CREATE VLAN=vlan-name VID=2..4094 [PROTECTED]
VLAN Interaction with STPs and Trunk Groups
Each VLAN and port can only belong to one Spanning Tree entity (STP). A port
cannot be added to a VLAN that is in a different STP from the VLANs to which
the port already belongs, with one exception. The exception is that an untagged
port in the default VLAN can be moved from the default VLAN to any other
VLAN in any STP, if the port belongs only to the default VLAN as an untagged
port.
For Rapier i Series switches only, a port can belong to more than one STP, and a
VLAN may have ports in more than one STP. VLANs can belong to multiple
STPs.
All the ports in a trunk group must have the same VLAN configuration: they
must belong to the same VLANs and have the same tagging status, and can
only be operated on as a group.
Generic VLAN Registration Protocol
(GVRP)
The GARP application GVRP allows routers in a network to dynamically share
VLAN membership information, to reduce the need for statically configuring
all VLAN membership changes on all switches in a network. See the Generic
Attribute Registration Protocol (GARP) chapter in the Rapier Switch Software
Reference.