Nokia 7210 SAS-M User Manual

System Management
254
7210 SAS-M, T, R6, R12, Mxp, Sx, S Basic System
Configuration Guide
3HE 16132 AAAB TQZZA Edition: 01
NTP uses stratum levels to define the number of hops from a reference clock. The
reference clock is treated as a stratum-0 device that is assumed to be accurate with
little or no delay. Stratum-0 servers cannot be used in a network. However, they can
be directly connected to devices that operate as stratum-1 servers. A stratum-1
server is an NTP server with a directly-connected device that provides Coordinated
Universal Time (UTC), such as a GPS or atomic clock.
The 7210 SAS devices cannot act as stratum-1 servers but can act as stratum-2
devices because a network connection to an NTP server is required.
The higher stratum levels are separated from the stratum-1 server over a network
path, thus a stratum-2 server receives its time over a network link from a stratum-1
server. A stratum-3 server receives its time over a network link from a stratum-2
server.
If the internal PTP process is used as a time source for System Time and OAM, it
must be specified as a server for NTP. If PTP is specified, the prefer parameter must
also be specified. After PTP has established a UTC traceable time from an external
grandmaster source, that clock will always be the time source into NTP, even if PTP
goes into time holdover.
The following NTP elements are supported:
• server mode
In this mode, the node advertises the ability to act as a clock source for other
network elements. By default, the node will, by default, transmits NTP packets
in NTP version 4 mode.
• authentication keys
These keys implement increased security support in carrier and other networks.
Both DES and MD5 authentication are supported, as well as multiple keys.
• symmetric active mode
In this mode, the NTP is synchronized with a specific node that is considered
more trustworthy or accurate than other nodes carrying NTP in the system. This
mode requires that a specific peer is set.
• broadcast
In this mode, the node receives or sends using a broadcast address.
• alert when NTP server is not available
Note: Use of the internal PTP time source for NTP promotes the internal NTP server to
stratum 1 level. This may impact the NTP network topology.

Nokia 7210 SAS-M Specifications

General

Brand	Nokia
Model	7210 SAS-M
Category	Cell Phone
Language	English