Forwarding Tagged And Untagged Frames - ZyXEL Communications MES-2110 User Manual

Chapter 12 VLAN

12.2.1 Forwarding Tagged and Untagged Frames

Each port on the MES-2110 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 MES-2110 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 MES-2110 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 28 IEEE 802.1Q VLAN Terminology
VLAN
PARAMETER
VLAN Type
VLAN
Administrative
Control
VLAN Tag Control
VLAN Port
98
TERM DESCRIPTION
Permanent VLAN This is a static VLAN created manually.
Dynamic VLAN This is a VLAN configured by a GVRP registration/
deregistration process.
Registration Fixed Fixed registration ports are permanent VLAN
members.
Registration Ports with registration forbidden are forbidden to
Forbidden join the specified VLAN.
Normal Ports dynamically join a VLAN using GVRP.
Registration
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.
Port VID This is the VLAN ID assigned to untagged frames
that this port received.
Acceptable Frame You may choose to accept both tagged and
Type untagged incoming frames, just tagged incoming
frames or just untagged incoming frames on a
port.
Ingress filtering If set, the MES-2110 discards incoming frames
for VLANs that do not have this port as a
member.
MES-2110 User's Guide