Cisco Cisco Packet Data Interworking Function (PDIF) Guía De Administador
System Settings
▀ Configuring System Timing
▄ Cisco ASR 5000 System Administration Guide
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server ip_address3
end
Notes:
By default context_name is set to local. This is the recommended configuration.
A number of options exist for the server command. Refer to the NTP Configuration Mode Commands chapter in
the Command Line Interface Reference for more information.
Enter the IP address of NTP servers using IPv4 dotted-decimal or IPv6 colon-separated-hexadecimal notation.
Important:
Configure the system with at least three (preferably four) NTP servers.
Save the configuration as described in Verifying and Saving Your Configuration.
Configuring NTP Servers with Local Sources
NTP can use network peers, local external clocks (such as GPS devices), or a local clock with no external source.
A local clock with no external source is usually a last-resort clock when no better clock is available. It is typically
configured on a site's intermediate NTP server so that when a WAN network outage occurs, hosts within the site can
continue to synchronize amongst themselves.
configured on a site's intermediate NTP server so that when a WAN network outage occurs, hosts within the site can
continue to synchronize amongst themselves.
You can configure this in ntpd or on many commercially available NTP devices. This local clock should always have a
high stratum number (8+) so that under normal conditions (when real sources are available) this local clock will not be
used.
high stratum number (8+) so that under normal conditions (when real sources are available) this local clock will not be
used.
Using a Load Balancer
The NTP daemon and protocol assume that each configured server is running NTP. If a NTP client is configured to
synchronize to a load balancer that relays and distributes packets to a set of real NTP servers, the load balancer may
distribute those packets dynamically and confuse the NTP client. NTP packets are latency and jitter sensitive. Relaying
them through a load balancer can confuse the NTP client and is not a supported practice.
synchronize to a load balancer that relays and distributes packets to a set of real NTP servers, the load balancer may
distribute those packets dynamically and confuse the NTP client. NTP packets are latency and jitter sensitive. Relaying
them through a load balancer can confuse the NTP client and is not a supported practice.
Verifying the NTP Configuration
Verify the NTP configuration is correct. Enter the following command at the Exec mode prompt:
show ntp associations
The output displays information about all NTP servers. See the output below for an example deploying two NTP
servers.
servers.