UTStarcom iSpirit 3026, Руководство пользователя

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3.1 Introduction to VLAN
This section will give detail information for VLAN:
Benefit of VLAN
VLAN ID
Member ports types of VLAN
VLAN relay
Data transmission in a VLAN
VLAN vs. Private VLAN
Subnetworks of VLAN
1.Benefit of VLAN
VLAN can extend a physical network to a large degree. Traditional physical networks can be
very small, usually with up to 1000 devices, while physical networks with VLAN partitions can
have 10,000 or even 100,000 devices. VLAN has the same functionality and characteristics as
the traditional physical network.
Advantages:
VLAN can control data flow in the network
In traditional networks, all broadcast packets are transmitted to all devices, no matter whether
needed or not, thus increasing the load of the network and the devices; While VLAN can
organize devices into one logical network when needed. One VLAN represents one broadcast
domain, broadcast packets can only transmit inside a VLAN, not across multiple VLANs. So
VLAN partition can control effectively data flow in a network.
VLAN can improve network security
Devices in a VLAN can only set up Layer 2 communication among themselves, communication
with another VLAN must go through Layer 3 transmission. Without Layer 3 transmission, no
communication is allowed between VLANs at all, thus VLAN can provide isolation and keep data
safety in a VLAN. For example, the “research” department in a company doesn’t want to share
data with the “marketing” department, then two VLANs can be created for them, one for each of
them, without Layer 3 transmission.
VLAN makes it more convenient to move devices
When a device in a traditional network is moved from one position to another, usually the
network administrator has to modify its configuration, which is inconvenient for users. For VLAN,
since a VLAN is a logical network, it can allocate devices in different locations into the same