Ntp Configuration Guidelines - Cisco DS-C9216I-K9 Configuration Manual

Chapter 6 Initial Configuration
If you only configure a peer, the most accurate peer takes on the role of the NTP server and the other
peer(s) act as a peer(s). Both machines end at the right time if they have the right time source or if they
point to the right NTP source.

NTP Configuration Guidelines

The following guidelines apply to all NTP configurations:
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If the network is configured robustly, even a server down time will not affect well-configured switches
in the network. displays a network with two NTP stratum 2 servers and two switches.
Figure 6-1
Stratum-2
Server-1
In this configuration, the switches were configured as explained below:
Stratum-2 Server-1
Stratum-2 Server-2
OL-7753-01
You should have a peer association with another switch only when you are sure that your clock is
reliable (which means that you are a client of a reliable NTP server).
Though a peer configured alone, will be the most accurate peer taking on the role of a server, the
configured peer should be used more as a back-up support. If more than one server is present, you
can have several switches point to one server, and the remaining to the another server, and then
configure peer association between these two sets. This forces the clock more reliable.
If you only have one server, it's better for all the switches have a client association with that server.
NTP Peer and Server Association
From lower stratum
server-1
Peer association
Server
association
Peer association
Switch-1
IP address 10.10.10.10
IP address 10.10.10.9
From lower stratum
server-2
Stratum-2
Server-2
Server
association
Switch-2
Switch-1
Switch-2
Cisco MDS 9000 Fabric Manager Switch Configuration Guide
NTP Configuration
IP address 10.10.10.1
NTP configuration:
NTP server 10.10.10.10
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NTP peer 10.10.10.2
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IP address 10.10.10.2
NTP configuration:
NTP server 10.10.10.9
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NTP peer 10.10.10.1
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6-2