Cabletron Systems 802.1Q Manual De Usuario

 

Virtual Local Area Networks

 

The primary benefit of the 802.1Q VLAN technology is that it provides 
localization of traffic. This function also offers improvements in security 
and performance to stations assigned to a VLAN.

While the localization of traffic to VLANs can improve security and 
performance, it imposes some restrictions on network devices that 
participate in the VLAN. Through the use of Filtering Database ID’s 
(FIDs) security can be implemented to enable or prevent users from one 
or more VLANs from communicating with each other. 

One or more VLANs can be assigned to a FID so that all the users that 
share a common FID can communicate with each other regardless of their 
VLAN affiliation. However, for the sake of security, the members of one 
FID cannot communicate with the members of another FID.

To set up a VLAN, all the network switch devices that are assigned to the 
VLAN must support the IEEE 802.1Q specification for VLANs. Before 
you attempt to implement a VLAN strategy, ensure that the switches 
under consideration support the IEEE 802.1Q specification.

 

To fully understand the operation and configuration of port based VLANs, 
it is essential to understand the definitions of several key terms.

 

A unique number (between 1 and 4094) that identifies a particular VLAN.

 

A 32-character alphanumeric name associated with a VLAN ID. The 
VLAN Name is intended to make user-defined VLANs easier to identify 
and remember. 

 

Addressing information that the device learns about a VLAN is stored in 
the filtering database assigned to that VLAN. Several VLANs can be 
assigned to the same FID to allow those VLANs to share addressing 
information. This enables the devices in the different VLANs to 
communicate with each other when the individual ports have been 
configured to allow communication to occur.