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Chapter 4
Initial Configuration
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m .
By configuring an IP address as a peer, the switch will obtain and provide time as required. The peer is
capable of providing time on its own and is capable of having a server configured. If both these instances
point to different time servers, your NTP service is more reliable. Thus, even if the active server link is
lost, you can still maintain the right time due to the presence of the peer.
If an active server fails, a configured peer helps in providing the NTP time. Provide a direct NTP server
Tip
association and configure a peer to ensure backup support if the active server fails.
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.
To configure NTP in a server association, follow these steps:
Command
Step 1
switch# config t
Step 2
switch(config)# ntp server 10.10.10.10
switch(config)#
Step 3
switch(config)# ntp peer 10.20.10.0
switch(config)#
Step 4
switch(config)# exit
switch#
Step 5
switch# copy running-config startup-config
Step 6
switch# show ntp peers
--------------------------------------------
Peer IP Address
--------------------------------------------
10.20.10.2
10.20.10.0
NTP Configuration Guidelines
The following guidelines apply to all NTP configurations:
•
•
•
Not even a server down time will affect well-configured switches in the network.
network with two NTP stratum 2 servers and two switches.
OL-6973-03, Cisco MDS SAN-OS Release 2.x
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).
A peer configured alone takes on the role of a server and should be used as backup. If you have two
servers, then you can have several switches point to one server, and the remaining switches to the
other server. Then you would configure peer association between these two sets. This forces the
clock to be more reliable.
If you only have one server, it's better for all the switches to have a client association with that server.
Purpose
Enters configuration mode.
Forms a server association with a server.
Forms a peer association with a peer. You can
specify multiple associations.
Returns to EXEC mode.
Saves your configuration changes to NVRAM.
Tip
Displays the configured server and peer
associations.
Serv/Peer
Note
Server
Peer
Cisco MDS 9000 Family Configuration Guide
Configuring Date and Time
This is one instance where you can save
the configuration as a result of an NTP
configuration change. You can issue this
command at any time.
A domain name is resolved only when
you have a DNS server configured.
Figure 4-3
displays a
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