ZyXEL Communications ES-2048 - Manual (Page 31)

ES-2000 Series Switch Support Notes
All contents copyright (c) 2006 ZyXEL Communications Corporation.
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Port-based VLANs are VLANs where the packet forwarding decision is based
on the destination MAC address and its associated port.
You must define
outgoing ports allowed for each port when using port-based VLANs. Note that VLAN
only governs the outgoing traffic, in the other word, it is unidirectional.
Therefore, if you wish to allow two subscriber ports to talk to each other, e.g.,
between conference rooms in a hotel, you must define the egress (outgoing
port) for both ports. An egress port is an outgoing port, that is, a port through
which a data packet leaves.
There are 5 hosts (Host A, B, C, D and E) connected to a 5-port layer-2 switch
which supported port-based VLAN.
Case 1: Host A and Host B can talk to each other, because they are in the
same VLAN group. But Host A and Host B can't talk to Host C, D, and E.
Port-based VLAN definition:
• Egress port for port 1: port 2
• Egress port for port 2: port 1
Case 2: There are 3 VLAN groups in the physical network. Host A and Host B
can talk to each other; they are in the same VLAN group 1. Host B and Host C
are in VLAN group 2. Host A, Host D and Host E are in VLAN group 3.