Black Box LPB2910A User Manual page 162

Port:

This i s t he l ogical p ort n umber o f t his r ow.
Mode:

The port mode (default is Access) determines the fundamental behavior of the port in question. A port can
operate i n o ne o f t hree m odes a s d escribed b elow.
When a particular mode is selected, the remaining fields in that row will be either grayed out or changeable
depending o n t he m ode i n q uestion. G rayed o ut f ields s how t he v alue t hat t he p ort w ill g et w hen t he m ode i s
applied.
Access:
Access ports are normally used to connect to end stations. Dynamic features like Voice VLAN may add the
port t o m ore V LANs b ehind t he s cenes. A ccess p orts h ave t he f ollowing c haracteristics:
• M ember o f e xactly o ne V LAN, t he P ort V LAN ( a.k.a. A ccess V LAN), w hich b y d efault i s 1 ,
• a ccepts u ntagged f rames a nd C -­‐tagged f rames,
• d iscards a ll f rames t hat a re n ot c lassified t o t he A ccess V LAN,
• o n e gress a ll f rames a re t ransmitted u ntagged.
Trunk:
Trunk ports can carry traffic on multiple VLANs simultaneously, and are normally used to connect to other
switches. T runk p orts h ave t he f ollowing c haracteristics:
• B y d efault, a t runk p ort i s a m ember o f a ll
• u nless VLAN Trunking is enabled on the port, frames classified to a VLAN that the port is not a member of
will b e d iscarded,
• b y default, all frames but frames classified to the Port VLAN (a.k.a. Native VLAN) get tagged on egress.
Frames c lassified t o t he P ort V LAN d o n ot g et C -­‐tagged o n e gress,
• e gress t agging c an b e c hanged t o t ag a ll f rames, i n w hich c ase o nly t agged f rames a re a ccepted o n i ngress,
• V LAN t runking m ay b e e nabled.
Hybrid:
Hybrid ports resemble trunk ports in many ways, but also have additional port configuration features. In
addition t o t he c haracteristics d escribed f or t runk p orts, h ybrid p orts h ave t hese a bilities:
• C an b e c onfigured t o b e V LAN t ag u naware, C -­‐tag a ware, S -­‐tag a ware, o r S -­‐custom-­‐tag a ware,
• i ngress f iltering c an b e c ontrolled,
• i ngress a cceptance o f f rames a nd c onfiguration o f e gress t agging c an b e c onfigured i ndependently.
Port V LAN:

Determines t he p ort's V LAN I D ( a.k.a. P VID). A llowed V LANs r ange f rom 1 t hrough 4 095; d efault i s 1 .
On ingress, frames get classified to the Port VLAN if the port is configured as VLAN unaware, the frame is
untagged, o r V LAN a wareness i s e nabled o n t he p ort, b ut t he f rame i s p riority t agged ( VLAN I D = 0 ).
On e gress, f rames c lassified t o t he P ort V LAN d o n ot g et t agged i f
Port VLAN. The Port VLAN is called an "Access VLAN" for ports in Access mode and Native VLAN for ports in
Trunk o r H ybrid m ode.
Port T ype:

Ports in hybrid mode allow for changing the port type, that is, whether a frame's VLAN tag is used to classify
the f rame o n i ngress t o a p articular V LAN, a nd i f s o, w hich T PID i t r eacts o n. L ikewise, o n e gress, t he P ort T ype
determines t he T PID o f t he t ag, i f a t ag i s r equired.
Unaware:
On ingress, all frames, whether carrying a VLAN tag or not, get classified to the Port VLAN, and possible tags
are n ot r emoved o n e gress.
C-­‐Port:
On i ngress, f rames w ith a V LAN t ag w ith T PID = 0 x8100 g et c lassified t o t he V LAN I D e mbedded i n t he t ag. I f a
frame is untagged or priority tagged, the frame gets classified to the Port VLAN. If frames must be tagged on
egress, t hey w ill b e t agged w ith a C -­‐tag.
S-­‐Port:
On ingress, frames with a VLAN tag with TPID = 0x8100 or 0x88A8 get classified to the VLAN ID embedded in
the t ag. I f a f rame i s u ntagged o r p riority t agged, t he f rame g ets c lassified t o t he P ort V LAN. I f f rames m ust b e
tagged o n e gress, t hey w ill b e t agged w ith a n S -­‐tag.
S-­‐Custom-­‐Port:
e xisting V
150
LANs. T his m ay b e l imited b y t he u se o f
E gress T agging c onfiguration i s s et t o u ntag
Publication date: Sept, 2015
A llowed V LANs,
Revision A1