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Cooper Bussmann 5073E-T Managed Ethernet Switch User Manual
Rev Version 1.1
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IQ Trunk Link
—This link type only supports multiple tagged VIDs. The IQ trunk
link is a segment that provides the link path for one or more VLAN-aware devices
(switches). A trunk port, connected to the trunk link, has an understanding of
tagged frame, which is used for communication among VLANs across switches.
Which frames of the specified VIDs will be forwarded depends on the values
filled in the Tagged VID column field. Use a comma to separate two VIDs.
NOTE A trunk port does not insert a tag into an untagged frame, and therefore
the untagged VID column field is not available. It is not necessary to type “1” in
the tagged VID. The trunk port will forward the frames of VLAN 1. The trunk port
must be connected to a trunk/hybrid port on the other switch. The tagged VID of
the two ports must be the same.
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Hybrid Link
—This link type supports untagged VID and multiple tagged VIDs.
The hybrid link is a segment that consists of access and trunk links. The hybrid
port has the features of both access and trunk ports. A hybrid port has a PVID
belonging to a particular VLAN, and also forwards the specified tagged frames
across switches for the purpose of VLAN communication.
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Hybrid Link (QinQ)
—(Double Tag VLAN) Link is segment that consists of Hybrid
QinQ Double Tag VLAN access and trunk links. QinQ is the technique also
known as provider bridging, Stacked VLANs.
The original 802.1Q VLAN specification allows a single Virtual Local Area
Network (VLAN) header to be inserted into an Ethernet frame. QinQ allows
multiple VLAN headers to be inserted into a single frame, an essential capability
for implementing Metro Ethernet network topologies.
In Metro Ethernet networks, fewer IP v4 addresses are used by using QinQ. A
QinQ type VLAN can save IPv4 addresses by populating groups of sub-VLANs in
a VLAN and utilizing the default gateway IP address of Double Tag VLAN sharing
the same IP subnet mask.
Double Tag VLAN in Layer 2 also provides enhanced security between
customers that are served by the same default gateway by segregating between
the sub-VLANs even when they are located in the same LAN and have the same
IP subnet mask.
In a multiple VLAN header context, out of convenience the term “VLAN tag” or
just “tag” for short is often used in place of “802.1Q VLAN header”. QinQ allows
multiple VLAN tags in an Ethernet frame; together these tags constitute a tag
stack. When used in the context of an Ethernet frame, a QinQ frame is a frame
that has two VLAN 802.1Q headers (double-tagged).
NOTE It is not necessary to type ‘1’ in the tagged VID. The hybrid port will
forward the frames of VLAN 1. The trunk port must be connected to a trunk/
hybrid port of the other switch. Both the tagged VID of the two ports need to be
the same.
Untagged VID
Assigns an untagged VID to the port. This field is available when the Link Type is set
to Access Link or Hybrid Link. Enter a number between 1 and 4094.
Tagged VID
Assigns a tagged VID to the port. This field is available when the Link Type is set to
Trunk Link or Hybrid Link. Enter a number between 1 and 4094.
Apply
Click to apply the settings.
