WESM zl Management and Configuration Guide WT.01.XX and greater

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Configuring the ProCurve Wireless Edge Services zl Module
Enabling Secure Network Time Protocol (NTP)
■ When—the number of seconds since a message has been received from
the remote resource
■ Peer Poll—the maximum interval between successive messages, in sec-
onds (always a power of 2 value, such as 8 or 64).
■ Reach—the status of the last eight NTP messages displayed in octal
format.
If an NTP packet reaches the resource successfully, the packet is assigned
the value of 1. Otherwise, it is assigned a value of 0. The results for eight
packets make up an eight-digit binary number. That number, expressed in
octal format, is the reach status.
You hope to see 377 for the reach status. This value indicates that all of
the last eight messages have reached the remote NTP device successfully,
producing this binary number: 11111111, which in octal is 377. If the most
recent NTP packet were lost, but the previous seven successful, the reach
status would be 376 (11111110).
The lost packet continues to be tracked over the next eight NTP messages.
In this example, if the next three packets were successful, the reach status
would become 370 (11110111). However, if the next three packets were
to fail as well, the reach status would become 360 (11110000).
Note that, as the 0 indicating the lost packet shifts, the reach status
decreases no matter the success of the following packets. Therefore a
decreasing value in the Reach column does not necessary indicate that
packets are no longer reaching the remote resource. For example, just
before the status returns to 377, it would read 177 (01111111).
■ Delay (sec)—the round-trip delay (in seconds) for NTP broadcasts
between the NTP resource and the module
■ Offset (sec)—the calculated offset (in seconds) between the clock on the
module and the NTP resource. The module adjusts its clock to match the
server’s time value. The offset gravitates toward zero over time, but never
completely reduces its offset to zero.
■ Dispersion (sec)—how scattered the time offsets are (in seconds) from an
Secure NTP time server.
To view more detailed information about a particular NTP association, select
the association and click the Details button. The Details screen is displayed.
(See Figure 2-99.)