Siemens S323, S223 Vlan, Enlarged Network Bandwidth, Cost-Effective Way, Strengthened Security

UMN:CLI	User Manual
	SURPASS hiD 6615 S223/S323 R1.5

8System Main Functions

8.1VLAN

The first step in setting up your bridging network is to define VLAN on your switch. VLAN is a bridged network that is logically segmented by customer or function. Each VLAN con- tains group of ports called VLAN members. On the VLAN network, packets received on a port are forwarded only to ports that belong to the same VLAN as the receiving port. Net- work devices in different VLANs cannot communicate with one another without a Layer 3 switching device to route traffic between the VLANs. These VLANs improve performance because they reduce the propagation of local traffic, and they improve security benefits because they completely separate traffic.

Enlarged Network Bandwidth

Users belonged in each different VLAN can use more enlarged bandwidth than no VLAN composition because they do not receive unnecessary Broadcast information. A properly implemented VLAN will restrict multicast and unknown unicast traffic to only those links necessary to only those links necessary to reach members of the VLAN associated with that multicast (or unknown unicast) traffic.

Cost-Effective Way

When you use VLAN to prevent unnecessary traffic loading because of broadcast, you can get cost-effective network composition since switch is not needed.

Strengthened Security

When using a shared-bandwidth LAN, there is no inherent protection provided against unwanted eavesdropping. In addition to eavesdropping, a malicious user on a shared LAN can also induce problems by sending lots of traffic to specific targeted users or net- work as a whole. The only cure is to physically isolate the offending user. By creating logical partitions with VLAN technology, we further enhance the protections against both unwanted eavesdropping and spurious transmissions. As depicted in Figure, a properly implemented port-based VLAN allows free communication among the members of a given VLAN, but does not forward traffic among switch ports associated with members of different VLANs. That is, a VLAN configuration restricts traffic flow to a proper subnet comprising exactly those links connecting members of the VLAN. Users can eavesdrop only on the multicast and unknown unicast traffic within their own VLAN presumably the configured VLAN comprises a set of logically related users.

User Mobility

By defining a VLAN based on the addresses of the member stations, we can define a workgroup independent of the physical location of its members. Unicast and multicast traffic (including server advertisements) will propagate to all members of the VLAN so that they can communicate freely among themselves.

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