ZyXEL Communications MES-2110, User Manual

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Chapter 11 VLAN
MES-2110 User’s Guide
84
11.2.1 Forwarding Tagged and Untagged Frames
Each port on the Switch is capable of passing tagged or untagged frames. To
forward a frame from an 802.1Q VLAN-aware switch to an 802.1Q VLAN-unaware
switch, the Switch first decides where to forward the frame and then strips off the
VLAN tag. To forward a frame from an 802.1Q VLAN-unaware switch to an 802.1Q
VLAN-aware switch, the Switch first decides where to forward the frame, and then
inserts a VLAN tag reflecting the ingress port's default VID. The default PVID is
VLAN 1 for all ports, but this can be changed.
A broadcast frame (or a multicast frame for a multicast group that is known by the
system) is duplicated only on ports that are members of the VID (except the
ingress port itself), thus confining the broadcast to a specific domain.
Please refer to the following table for common IEEE 802.1Q VLAN terminology.
Table 27 IEEE 802.1Q VLAN Terminology
VLAN
PARAMETER
TERM DESCRIPTION
VLAN Type Permanent VLAN This is a static VLAN created manually.
Dynamic VLAN This is a VLAN configured by a GVRP registration/
deregistration process.
VLAN
Administrative
Control Registration Fixed Fixed registration ports are permanent VLAN
members.
Registration
Forbidden Ports with registration forbidden are forbidden to
join the specified VLAN.
Normal
Registration Ports dynamically join a VLAN using GVRP.
VLAN Tag Control Tagged Ports belonging to the specified VLAN tag all
outgoing frames transmitted.
Untagged Ports belonging to the specified VLAN don't tag all
outgoing frames transmitted.
VLAN Port Port VID This is the VLAN ID assigned to untagged frames
that this port received.
Acceptable Frame
Type You may choose to accept both tagged and
untagged incoming frames, just tagged incoming
frames or just untagged incoming frames on a
port.
Ingress filtering If set, the Switch discards incoming frames for
VLANs that do not have this port as a member.