Milan Technology MIL-S3570 manual Virtual LAN Vlan

3.5 Virtual LAN (VLAN)

Each port of the switch unit connects to one individual LAN segment. There can be many Ethernet nodes located on each segment. The switch performs network data forwarding between different LAN segments. It allows Ethernet nodes located on different segments to communicate with each other. Basically, all Ethernet nodes are in one single LAN.

A Virtual LAN (VLAN) is a logical, independent workgroup within a network. The member in this work group communicate as if they are sharing the same physical LAN segment. VLANs are not limited by the hardware constraints that physically connect traditional LAN segments to a network. As a result, VLANs can define a network into multiple logical configurations.

Because VLANs are self-contained, only the devices within the same VLAN can communicate with each other. If a device in one VLAN wants to communicate with a device in another VLAN, the traffic must go through a router. This would enhance the security of the network. In addition, broadcasts from servers within each group would go to the members of its own VLAN. This ensures that broadcasts cannot cause a network meltdown due to traffic volume.

Implementation

The VLAN implementation of this switch allows up to 256 VLANs in one switch. By using explicit or implicit VLAN tagging and the GARP/GVRP protocol (IEEE 802.1p and 802.1Q), VLANs may span across multiple switches. A MAC address can belong to multiple VLANs, and a switched port may be associated with multiple VLANs.

Static Definitions of VLAN Membership

The switch defines VLAN membership based on ports. Port based VLANs are organized by physical port numbers. The definitions are configured through the supported network management console.

Dynamic Learning of VLAN Membership

While port based VLAN only defines static binding between a VLAN and its port members, the MAC address database associated with each port number and VLAN is learned and built up dynamically by the switch at run time.

Dynamic Learning of Remote VLAN

In addition to adding and deleting VLAN member ports through network management console software statically, the switch also supports GVRP (GARP VLAN Registration Protocol). GVRP allows for dynamic registration of VLAN port numbers within a switch and across multiple switches. It is also used to communicate VLAN registration information to other VLAN-aware switches, so that a VLAN member can be covered by a wide range of switches in a network. GVRP allows both VLAN-aware workstations and switches to issue and revoke VLAN memberships. The switches register and propagate VLAN membership to all ports belonging to the active topology of the VLAN.

VLAN Configuration

The switch currently provides a Local/Remote Management Console Interface for VLAN configuration and management. An SNMP-based

VLAN MIB is also provided. Combining the hardware and software functions, the switch supports Intra- VLAN Communication and Inter-VLAN Communication.

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