Vlan trunking, Figure 59: configuring vlan trunking, Vlan t – LevelOne GTL-2691 User Manual

Page 195

HAPTER

| Interface Configuration

VLAN Trunking

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VLAN T

RUNKING

Use the Interface > VLAN Trunking page to allow unknown VLAN groups to

pass through the specified interface.

CLI R

EFERENCES

◆

OMMAND

SAGE

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Use this feature to configure a tunnel across one or more intermediate

switches which pass traffic for VLAN groups to which they do not

belong.

The following figure shows VLANs 1 and 2 configured on switches A and

B, with VLAN trunking being used to pass traffic for these VLAN groups

across switches C, D and E.

Figure 59: Configuring VLAN Trunking

Without VLAN trunking, you would have to configure VLANs 1 and 2 on

all intermediate switches – C, D and E; otherwise these switches would

drop any frames with unknown VLAN group tags. However, by enabling

VLAN trunking on the intermediate switch ports along the path

connecting VLANs 1 and 2, you only need to create these VLAN groups

in switches A and B. Switches C, D and E automatically allow frames

with VLAN group tags 1 and 2 (groups that are unknown to those

switches) to pass through their VLAN trunking ports.

◆

To prevent loops from forming in the spanning tree, all unknown VLANs

will be bound to a single instance (either STP/RSTP or an MSTP

instance, depending on the selected STA mode).

◆

If both VLAN trunking and ingress filtering are disabled on an interface,

packets with unknown VLAN tags will still be allowed to enter this

interface and will be flooded to all other ports where VLAN trunking is

enabled. (In other words, VLAN trunking will still be effectively enabled

for the unknown VLAN).

ARAMETERS

These parameters are displayed:

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Interface – Displays a list of ports or trunks.

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Port – Port Identifier. (Range: 1-26)