Interlogix NS3550-8T-2S User Manual - Manual (Page 98)

User’s Manual of NS3550-8T-2S
98
4.6 VLAN
4.6.1 VLAN Overview
A Virtual Local Area Network (VLAN) is a network topology configured according to a logical scheme rather than the physical
layout. VLAN can be used to combine any collection of LAN segments into an autonomous user group that appears as a single
LAN. VLAN also logically segment the network into different broadcast domains so that packets are forwarded only between
ports within the VLAN. Typically, a VLAN corresponds to a particular subnet, although not necessarily.
VLAN can enhance performance by conserving bandwidth, and improve security by limiting traffic to specific domains.
A VLAN is a collection of end nodes grouped by logic instead of physical location. End nodes that frequently communicate with
each other are assigned to the same VLAN, regardless of where they are physically on the network. Logically, a VLAN can be
equated to a broadcast domain, because broadcast packets are forwarded to only members of the VLAN on which the
broadcast was initiated.
21. No matter what basis is used to uniquely identify end nodes and assign these nodes VLAN
membership, packets cannot cross VLAN without a network device performing a routing
function between the VLAN.
22. The Managed Switch supports IEEE 802.1Q VLAN. The port untagging function can be used
to remove the 802.1 tag from packet headers to maintain compatibility with devices that are
tag-unaware.
23. The Switch's default is to assign all ports to a single 802.1Q VLAN named DEFAULT_VLAN.
As new VLAN is created, the member ports assigned to the new VLAN will be removed from
the DEFAULT_ VLAN port member list. The DEFAULT_VLAN has a VID = 1.
This section has the following items:
 VLAN Basic Information
Displays VLAN information
 VLAN Port Configuration Enables VLAN group
 VLAN Memberships Configures the VLAN membership
 VLAN Membership Status Displays VLAN membership status
 VLAN Port Status Displays VLAN port status
 Private VLAN Creates/removes primary or community VLANs
 Port Isolation Enables/disables port isolation on port
 MAC-based VLAN Configures the MAC-based VLAN entries
 MAC-based VLAN Status Displays MAC-based VLAN entries
 IP Subnet-based VLAN Configures the IP Subnet-based VLAN entries
 Protocol-based VLAN Configures the protocol-based VLAN entries
 Protocol-based VLAN
Membership
Displays the protocol-based VLAN entries
4.6.2 IEEE 802.1Q VLAN
In large networks, routers are used to isolate broadcast traffic for each subnet into separate domains. This Managed Switch
provides a similar service at Layer 2 by using VLANs to organize any group of network nodes into separate broadcast domains.
VLANs confine broadcast traffic to the originating group, and can eliminate broadcast storms in large networks. This also
provides a more secure and cleaner network environment.
An IEEE 802.1Q VLAN is a group of ports that can be located anywhere in the network, but communicate as though they belong
to the same physical segment.
VLANs help to simplify network management by allowing you to move devices to a new VLAN without having to change any
physical connections. VLANs can be easily organized to reflect departmental groups (such as Marketing or R&D), usage groups
(such as e-mail), or multicast groups (used for multimedia applications such as videoconferencing).
VLANs provide greater network efficiency by reducing broadcast traffic, and allow you to make network changes without having
to update IP addresses or IP subnets. VLANs inherently provide a high level of network security since traffic must pass through
a configured Layer 3 link to reach a different VLAN.
This Managed Switch supports the following VLAN features:
 Up to 255 VLANs based on the IEEE 802.1Q standard
 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