Enterasys Networks 2E253, 2H253, 2H252, 2H258 manual Benefits and Restrictions, Vlan Terms, Ingress

Benefits and Restrictions

12.3 BENEFITS AND RESTRICTIONS

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 IDs (FDB IDs) 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 an FDB ID so that all the users that share a common FDB ID can communicate with each other regardless of their VLAN affiliation. However, for the sake of security, the members of one FDB ID cannot communicate with the members of another

FDB ID.

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.

12.4 VLAN TERMS

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

Table 12-1 VLAN Terms and Definitions

VLAN Term	Definition
VLAN ID	A unique number (between 1 and 4094) that identifies a
	particular VLAN. Up to 1000 VLANs can be created on one
	SmartSwitch.
VLAN Name	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.
Egress	Output direction of data from a network device.
Ingress	Incoming direction of data to a network device.

12-4VLAN Operation and Network Applications