ZyXEL Communications ES-2108 User Manual

ES-2108 Series User’s Guide

Chapter 7 Basic Setting 

65

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.

Use Time Server 

when Bootup

Enter the time service protocol that your timeserver uses. Not all time servers 

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.
When you select the Daytime (RFC 867) format, the switch displays the day, 

month, year and time with no time zone adjustment. When you use this format it is 

recommended that you use a Daytime timeserver within your geographical time 

zone.
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 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 reset the fields to your previous configuration.

Table 9   General Setup  (continued)