ZyXEL Communications GS1920-48HPv2, Руководство пользователя

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Chapter 8 Basic Setting
GS1920v2 Series User’s Guide
81
8.4 Intro duc tio n to VLANs
A VLAN (Virtual Local Area Network) allows a physical network to be partitioned into multiple logical
networks. Devices on a logical network belong to one group. A device can belong to more than one
group. With VLAN, a device cannot directly talk to or hear from devices that are not in the same
group(s); the traffic must first go through a router.
In MTU (Multi-Tenant Unit) applications, VLAN is vital in providing isolation and security among the
subscribers. When properly configured, VLAN prevents one subscriber from accessing the network
resources of another on the same LAN, thus a user will not see the printers and hard disks of another user
in the same building.
VLAN also increases network performance by limiting broadcasts to a smaller and more manageable
logical broadcast domain. In traditional switched environments, all broadcast packets go to each and
every individual port. With VLAN, all broadcasts are confined to a specific broadcast domain.
Note: VLAN is unidirectional; it only governs outgoing traffic.
See Chapter 9 on page 107 for information on port-based and 802.1Q tagged VLANs.
Daylight Saving
Time Daylight saving is a period from late spring to early fall when many countries set their clocks
ahead of normal local time by one hour to give more daytime light in the evening.
Select this option if you use Daylight Saving Time.
Start Date Configure the day and time when Daylight Saving Time starts if you selected
Da ylig ht Sa ving
Tim e
. The time is displayed in the 24 hour format. Here are a couple of examples:
Daylight Saving Time starts in most parts of the United States on the second Sunday of March.
Each time zone in the United States starts using Daylight Saving Time at 2 A.M. local time. So in
the United States you would select
Se c o nd
,
Sunda y
,
Ma rc h
and
2:00
.
Daylight Saving Time starts in the European Union on the last Sunday of March. All of the time
zones in the European Union start using Daylight Saving Time at the same moment (1 A.M. GMT
or UTC). So in the European Union you would select
La st
,
Sunda y
,
Ma rc h
and the last field
depends on your time zone. In Germany for instance, you would select
2:00
because
Germany's time zone is one hour ahead of GMT or UTC (GMT+1).
End Date Configure the day and time when Daylight Saving Time ends if you selected
Da ylig ht Sa ving
Tim e
. The time field uses the 24 hour format. Here are a couple of examples:
Daylight Saving Time ends in the United States on the first Sunday of November. Each time
zone in the United States stops using Daylight Saving Time at 2 A.M. local time. So in the United
States you would select
First
,
Sunda y
,
No ve m b e r
and
2:00
.
Daylight Saving Time ends in the European Union on the last Sunday of October. All of the time
zones in the European Union stop using Daylight Saving Time at the same moment (1 A.M. GMT
or UTC). So in the European Union you would select
La st
,
Sunda y
,
O c to b e r
and the last field
depends on your time zone. In Germany for instance, you would select
2:00
because
Germany's time zone is one hour ahead of GMT or UTC (GMT+1).
Apply Click
Apply
to save your changes to the Switch’s run-time memory. The Switch loses these
changes if it is turned off or loses power, so use the
Sa ve
link on the top navigation panel to
save your changes to the non-volatile memory when you are done configuring.
Cancel Click
C a nc e l
to begin configuring this screen afresh.
Table 14 Basic Setting > General Setup (continued)
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