Black Box LPB2910A User Manual page 163

On ingress, frames with a VLAN tag with a TPID = 0x8100 or equal to the Ethertype configured for Custom-­‐S
ports get classified to the VLAN ID embedded in the tag. If a frame is untagged or priority tagged, the frame
gets classified to the Port VLAN. If frames must be tagged on egress, they will be tagged with the custom
S-­‐tag.
Ingress F iltering:

Hybrid p orts a llow f or c hanging i ngress f iltering. A ccess a nd T runk p orts a lways h ave i ngress f iltering e nabled.
If i ngress f iltering i s e nabled ( checkbox i s c hecked), f rames c lassified t o a V LAN t hat t he p ort i s n ot a m ember
of g et d iscarded.
If ingress filtering is disabled, frames classified to a VLAN that the port is not a member of are accepted and
forwarded t o t he s witch e ngine. H owever, t he p ort w ill n ever t ransmit f rames c lassified t o V LANs t hat i t i s n ot
a m ember o f.
VLAN T runking:

Trunk a nd H ybrid p orts a llow f or e nabling V LAN t runking. W hen V LAN t runking i s e nabled, f rames c lassified t o
unknown VLANs are accepted on the port whether ingress filtering is enabled or not. This is useful in
scenarios where a cloud of intermediary switches must bridge VLANs that haven't been created. By
configuring the ports that connect the cloud of switches as trunking ports, they can seamlessly carry those
VLANs f rom o ne e nd t o t he o ther.
Ingress A cceptance:

Hybrid p orts a llow f or c hanging t he t ype o f f rames t hat a re a ccepted o n i ngress.
Tagged a nd U ntagged
Both t agged a nd u ntagged f rames a re a ccepted.
Tagged O nly
Only t agged f rames a re a ccepted o n i ngress. U ntagged f rames a re d iscarded.
Untagged O nly
Only u ntagged f rames a re a ccepted o n i ngress. T agged f rames a re d iscarded.
Egress T agging :

Ports i n T runk a nd H ybrid m ode m ay c ontrol t he t agging o f f rames o n e gress.
Untag P ort V LAN
Frames c lassified t o t he P ort V LAN a re t ransmitted u ntagged. O ther f rames a re t ransmitted w ith t he r elevant
tag.
Tag A ll
All f rames, w hether c lassified t o t he P ort V LAN o r n ot, a re t ransmitted w ith a t ag.
Untag A ll
All f rames, w hether c lassified t o t he P ort V LAN o r n ot, a re t ransmitted w ithout a t ag.
This o ption i s o nly a vailable f or p orts i n H ybrid m ode.
Allowed V LANs:

Ports in Trunk and Hybrid mode may control which VLANs they are allowed to become members of. Access
ports c an o nly b e m ember o f o ne V LAN, t he A ccess V LAN
The field's syntax is identical to the syntax used in the Existing VLANs field. By default, a port may become a
member o f a ll p ossible V LANs, a nd i s s et t o 1 -­‐4095.
The f ield m ay b e l eft e mpty, w hich m eans t hat t he p ort w ill n ot b e m ember o f a ny o f t he e xisting V LANs, b ut i f
it i s c onfigured f or
Forbidden V LANs:

A port may be configured to never be a member of one or more VLANs. This is particularly useful when
dynamic V LAN p rotocols l ike M VRP a nd G VRP m ust b e p revented f rom d ynamically a dding p orts t o V LANs.
The t rick i s t o m ark s uch V LANs a s f orbidden o n t he p ort i n q uestion. T he s yntax i s i dentical t o t he s yntax u sed
in the Existing
member o f a ll p ossible V LANs.
V LAN T runking i t w ill s till b e a ble t o c arry a ll u nknown V LANs.
VLANs field. By default, the field is left blank, which means that the port may become a
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Publication date: Sept, 2015
Revision A1