ZyXEL VES-1616 Manuel d'utilisateur télécharger pdf (Page 26)

ZyXEL VES-1616/24FA-5x Series Support Notes

known as the VLAN Group. A station can belong to more than one group.

Stations in the same VLAN group can communicate with each other. With VLAN,

a station cannot directly communicate with stations that are not in the same VLAN

group(s); the traffic must first go through a router.

In GePON applications, VLAN is vital in providing isolation and security among

subscribers. When properly configured, VLAN prevents one subscriber from

accessing the network resources of another on the same LAN. Thus a user will

not see the printers and hard disks of another user in the same building.

VLAN also increases network performance by limiting broadcasts to a smaller and

more manageable logical broadcast domain. A VLAN group is a broadcast

domain. In traditional Layer-2 switched environments, all broadcast packets go to

each and every individual port. With VLAN, all broadcasts are confined to a

specific broadcast domain.

There are two VLAN implementations: Port-based VLAN and IEEE 802.1q

Tagged VLAN. VES-1616F-3X supports both VLAN implementations. The major

difference between both VLAN implementations is that Tagged VLAN can cross

Layer-2 switches but Port-based VLAN cannot.

Port-based VLAN

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.

In the following figure, five hosts (A, B, C, D and E) are connected to a 5-port

layer-2 switch which supported port-based VLAN.

Case 1:

Hosts A and B can communicate with each other, because they are in the same

VLAN group. But Hosts A and B cannot communicate with Hosts C, D, and E.

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ZyXEL VES-1616 Manuel d'utilisateur Page 26