Cisco Cisco Packet Data Gateway (PDG) Guía De Instalación
Initial System Configuration
▀ Set System Timing
▄ ASR 5500 Installation Guide
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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
To verify the NTP Configuration, enter the show ntp associations command at the Exec mode. The output displays
information about all NTP servers.
information about all NTP servers.
The table below lists and briefly describes the parameters that appear in the output of the show ntp associations
command.
command.
Table 21. Output Parameters for show ntp associations
Column Title
Description
remote
Lists the current NTP servers. One of these characters precedes each IP address to show the server’s current
condition:
condition:
() Rejected/No response
X False tick
(.) Excess
- Outlyer
+ Candidate
# Selected
* System peer
(o) PPS peer
refid
Last reported NTP reference to which the server is synchronizing.
st
NTP server stratum level.
t
Communication type: broadcast, multicast, etc.
when
Number of seconds since the last contact.
poll
Polling interval between the system and the NTP server.
reach
Octal value of the reachability shift register indicating which responses were received for the previous eight
polls to this NTP server.
polls to this NTP server.
delay
Round-trip delay (in milliseconds) for messages exchanged between the system and the NTP server.
offset
Number of milliseconds by which the system clock must be adjusted to synchronize it with the NTP server.
jitter
Jitter in milliseconds between the system and the NTP server.