System information

Chapter 2: Configuring System Information | 41
GS752TXS Smart Switch Software Administration Manual
• Delay. More than ReachableTime milliseconds have elapsed since the last positive
confirmation was received that the forward path was functioning properly. A packet
was sent within the last DELAY_FIRST_PROBE_TIME seconds. If no reachability
confirmation is received within DELAY_FIRST_PROBE_TIME seconds of entering
the DELAY state, send a neighbor solicitation message and change the state to
PROBE.
• Probe. A reachability confirmation is actively sought by resending neighbor
solicitation messages every RetransTimer milliseconds until a reachability
confirmation is received.
• Last Updated. Time since the address was confirmed to be reachable.
To configure the network information for a IPv6 network:
• Refresh. Refreshes the screen with most recent data.
• Clear. Clear IPv6 neighbors on selected interface or all interfaces.
Time
GS752TXS Smart Switch software supports the Simple Network Time Protocol (SNTP). You
can also set the system time manually
SNTP assures accurate network device clock time synchronization up to the millisecond.
Time synchronization is performed by a network SNTP server. GS752TXS Smart Switch
software operates only as an SNTP client and cannot provide time services to other systems.
Time sources are established by Stratums. Stratums define the accuracy of the reference
clock. The higher the stratum (where zero is the highest), the more accurate the clock. The
device receives time from stratum 1 and above since it is itself a stratum 2 device.
The following is an example of stratums:
• Stratum 0: A real-time clock is used as the time source, for example, a GPS system.
• Stratum 1: A server that is directly linked to a Stratum 0 time source is used. Stratum 1
time servers provide primary network time standards.
• Stratum 2: The time source is distanced from the Stratum 1 server over a network path.
For example, a Stratum 2 server receives the time over a network link, via NTP, from a
Stratum 1 server.
Information received from SNTP servers is evaluated based on the time level and server
type.
SNTP time definitions are assessed and determined by the following time levels:
• T1: Time at which the original request was sent by the client.
• T2: Time at which the original request was received by the server.
• T3: Time at which the server sent a reply.
• T4: Time at which the client received the server's reply.
The device can poll Unicast server types for the server time.