ZyXEL Communications Dimension ES-3024, Руководство пользователя, Страница: 63 / 212

Dimension ES-3024 Ethernet Switch
Basic Setting 6-5
Table 6-2 General Setup
LABEL DESCRIPTION
Use Time Server
When Bootup Enter the time service protocol that a timeserver sends when you turn on the switch. Not all
timeservers support all protocols, so you may have to use trial and error to find a protocol that
works. The main differences between them are the time format.
Daytime (RFC 867) format is day/month/year/time zone of the server.
Time (RFC-868) format displays a 4-byte integer giving the total number of seconds since
1970/1/1 at 0:0:0.
NTP (RFC-1305) is similar to Time (RFC-868).
None is the default value. Enter the time manually. Each time you turn on the switch, the time
and date will be reset to 2000-1-1 0:0.
Time Server IP
Address Enter the IP address (or URL if you configure a domain name server in the IP Setup screen) of
your timeserver. The switch searches for the timeserver for up to 60 seconds. If you select a
timeserver that is unreachable, then this screen will appear locked for 60 seconds. Please
wait.
Current Time This field displays the time you open this menu (or refresh the menu).
New Time
(hh:min:ss) Enter the new time in hour, minute and second format. The new time then appears in the
Current Time field after you click Apply .
Current Date This field displays the date you open this menu.
New Date (yyyy-
mm-dd) Enter the new date in year, month and day format. The new date then appears in the Current
Date field after you click Apply .
Time Zone Select the time difference between UTC (Universal Time Coordinated, formerly known as
GMT, Greenwich Mean Time) and your time zone from the drop-down list box.
Apply Click Apply to save the settings.
Cancel Click Cancel to start configuring the screen again.
6.4 Introduction 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 that VLAN is unidirectional; it only governs outgoing traffic.