Cabletron Systems ELS100-24TXG ELS100-24TXG VLAN Configuration

84 Virtual LANs (VLANs) ELS100-24TXG

to all connected stations and interfa ces. When frame s are forwarde d back

to destination end stations, the tag may or may not be stripped off,

depending on the configuration of the end station and the switch port.

By using 802.1Q tagged VLANs, users from physically dispersed

locations can be formed into gr oups by assigni ng them to s pecifi c VLANs.

Broadcast and multicast traffic for these specific VLANs can be directed

across the network without being radiated out to stations that are not

members of the same VLANs. Up to 4094 different VLANs can be

specified by the 802.1Q tag, thus permitting the configuration of up to

4094 virtual workgroups. This implementation is nonintrusive to end-

station applications and the associated clients.

ELS100-24TXG VLAN Configuration

VLAN operation on the ELS100-24TXG is disabled by default. When

VLANs are enabled, all frames are transfer red internally throug h the

switch with a VLAN tag . This tag may already be on the frame entering

the switch, or added to the frame by the swi tch. VLAN i nformatio n already

existing on frames e n t ering the switch is aut omatically handled by the

switch. The ELS100-24TXG l earns VLAN info rmation from t agged f rames

and appropriately switches frames out the proper ports based on this

information. The co nf iguration of VLANs f o r frames entering the switch

without tags must be m a de by the user of the swi t ch. This configurati o n

can be made either through the VLAN Menu in the console interface or

via SNMP. The paramet ers used to configur e V LANs on the ELS100-

24TXG are explained below.

The VLAN ID is used to uniquely identify different VLANs on a network.

The VLAN ID information is contained in the 802.1Q tag header on a

frame, and so identifies the VLAN to whi ch a frame b elongs. The ELS100-

24TXG recognizes VLAN IDs in the tags on frames entering the switch,

and can also add tags wi th an appropriate VLA N ID to untagged frames.

When configuring VLAN s on the ELS100-24TXG, i ndividual ports are

assigned to specific VLANs by setting the Port VLAN ID (PVID) for each

port. Frames entering the switch which are untagged are automatically

assigned a VLAN ID by the switch based on the PVID of the incoming

port. The Ports in VLAN parameter makes the assignment of ports to

PVIDs. An individual port can on l y be as si gn ed to a single PVID with this

parameter.