Web Management Guide-R04

Table Of Contents

Chapter 5

| VLAN Configuration

IEEE 802.1Q VLANs

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disable GVRP on the boundary ports to prevent advertisements from being

propagated, or forbid those ports from joining restricted VLANs.

Note:

If you have host devices that do not support GVRP, you should configure

static or untagged VLANs for the switch ports connected to these devices (as

described in “Adding Static Members to VLANs” on page 173). But you can still

enable GVRP on these edge switches, as well as on the core switches in the

network.

Figure 80: Using GVRP

Forwarding Tagged/Untagged Frames

If you want to create a small port-based VLAN for devices attached directly to a

single switch, you can assign ports to the same untagged VLAN. However, to

participate in a VLAN group that crosses several switches, you should create a VLAN

for that group and enable tagging on all ports.

Ports can be assigned to multiple tagged or untagged VLANs. Each port on the

switch is therefore capable of passing tagged or untagged frames. When

forwarding a frame from this switch along a path that contains any VLAN-aware

devices, the switch should include VLAN tags. When forwarding a frame from this

switch along a path that does not contain any VLAN-aware devices (including the

destination host), the switch must first strip off the VLAN tag before forwarding the

frame. When the switch receives a tagged frame, it will pass this frame onto the

VLAN(s) indicated by the frame tag. However, when this switch receives an

untagged frame from a VLAN-unaware device, it first decides where to forward the

frame, and then inserts a VLAN tag reflecting the ingress port’s default VID.

Port-based VLAN

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