Management and Configuration Guide (Includes ACM xl) 2005-12

6-42 ProCurve Secure Access 700wl Series Management and Configuration Guide
Configuring the Network
Control Servers as equivalent NTP time servers. Transient failure of either of the Access Control Servers
does not adversely impact overall system timekeeping as the internal hardware clock on the surviving
systems ensures reasonable time continuity, the Access Controllers subsequently re-synchronize with
the Access Control Servers when they come back online.
If DHCP is enabled, and the DHCP server is configured with the NTP option for ntp-servers, the Access
Control Server will update its configuration to the NTP server specified in the DHCP server
configuration. Also, the Time & Date page will display the IP address of the NTP server and the
Set time
using network time server
will be checked.
If DHCP is not enabled, or if the NTP option is not configured for the DHCP server, you will need to set
the date and time manually and ensure the
Set time using network time server is not checked.
Alternatively, you can specify the NTP servers and check the
Set time using network time server for the
Access Control Server in the Date & Time page.
In a redundant 700wl Series system, it is important to set the clock on the Access Control Servers as
closely as practically possible using external means to avoid the resultant averaged time to be
representative of the actual time. Alternatively, you can specify the NTP servers and check the
Set time
using network time server
for both Access Control Servers. The preferred primary Access Control Server
and the secondary Access Control Server need to be configured with the same settings—either setting
the date and time manually, or specifying the NTP servers.
Since the Access Controllers synchronize their clocks to the Access Control Server, you do not need to
specify the NTP servers on the Access Controllers. However, sometimes Access Controllers are
deployed in a geographically distant location from the Access Control Server and due to some network
latency issues, the remote Access Controllers’ clocks may be less accurate. In this case, configuring the
remote Access Controllers to use a closer, lower latency, NTP server it is recommended.
Note:
If any Access Controller in a 700wl Series system is configured to use an NTP server, then the
Access Control Server should be configured to use an NTP server as well.
You use the Time and Date page to set the time zones and to set the date and time, either manually or
using a network time server. You can set the date and time separately for each system component, but
since the Access Control Server acts as the NTP server you should only need to set the time on it.
Note:
There may be a delay of several minutes before all 700wl Series system components times are
synchronized.
Note: If you are using NTP to get the date and time, the underlying GMT/UTC time difference between
the Access Control Server and its associated Access Controllers should be less than 900 seconds for the
clocks to be synchronized. A variance in (GMT/UTC) time between the Access Control Server and the
Access Controller clocks greater than 900 seconds generally cannot be synchronized by NTP without
rebooting the Access Controller. Having Access Controller and Access Control Server clocks start off with
a high initial variance is not recommended.
To configure the time and date for one or more components, do the following:
Step 1. Click the Date & Time tab from any page in the Network module.
The Date & Time page appears. See Figure 6-25.