SMC Networks 1000BASE-X Manual De Usuario

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addresses or IP subnets. VLANs inherently provide a high level of network 
security, since traffic must pass through a Layer 3 switch or a router to 
reach a different VLAN.
This switch supports the following VLAN features:
Up to 256 VLANs based on the IEEE 802.1Q standard
Distributed VLAN learning across multiple switches using explicit or 
implicit tagging 
Port overlapping, allowing a port to participate in multiple VLANs
End stations can belong to multiple VLANs
Passing traffic between VLAN-aware and VLAN-unaware devices 
Priority tagging 
Port trunking with VLANs
Assigning Ports to VLANs
Before enabling VLANs for the switch, you must first assign each port to 
the VLAN group(s) it will participate in. (By default all ports are assigned 
to VLAN 1 as untagged ports.) Add a port as a tagged port (that is, a port 
attached to a VLAN-aware device) if you want it to carry traffic for one or 
more VLANs and the device at the other end of the link also supports 
VLANs. Then assign the port at the other end of the link to the same 
VLAN(s). However, if you want a port on this switch to participate in one 
or more VLANs, but the device at the other end of the link does not 
support VLANs, then you must add this port as an untagged port (that is, 
a port attached to a VLAN-unaware device). 
Port-based VLANs are tied to specific ports. The switch’s forwarding 
decision is based on the destination MAC address and its associated port. 
Therefore, to make valid forwarding and flooding decisions, the switch 
learns the relationship of the MAC address to its related port—and thus to 
the VLAN—at run-time. When the switch receives a frame, it assigns the