SYSTEM ADMINISTRATOR GUIDE     34/1543-CRA 119 1170/1-V1 Uen A    

Configuring NTP

© Copyright Ericsson AB 2009. All rights reserved.

Disclaimer

No part of this document may be reproduced in any form without the written permission of the copyright owner. The contents of this document are subject to revision without notice due to continued progress in methodology, design and manufacturing. Ericsson shall have no liability for any error or damage of any kind resulting from the use of this document.

Trademark List

SmartEdge is a registered trademark of Telefonaktiebolaget L M Ericsson.

Contents

1Overview

2

Configuration and Operations Tasks
2.1Configure the NTP Server IP Address
2.2Configure NTP Peer Associations (Optional)
2.3Configure Slowsync (Optional)
2.4Operations Tasks

3

Configuration Examples


1   Overview

This document provides an overview of the Network Time Protocol (NTP) features supported by the SmartEdge® router and describes the tasks performed to configure, monitor, and administer NTP. This document also provides NTP configuration examples.

NTP exchanges timekeeping information between servers and clients through the Internet to synchronize clocks. NTP makes estimates based on several variables, including network delay, dispersion of packet exchanges, and clock offset. Extremely reliable sources, such as radio clocks and Global Positioning System (GPS) satellite timing receivers, act as primary servers. Company or campus servers can act as secondary time servers. To reduce overhead, secondary servers distribute time to attached local hosts.

The SmartEdge router supports NTP as described in RFC 1305, Network Time Protocol. Although the default version is version 3, the SmartEdge router also supports NTP versions 1 and 2. On a SmartEdge router, NTP operates in client mode only. The SmartEdge router can be synchronized by a remote NTP server, but the remote server cannot be synchronized by the SmartEdge router.

2   Configuration and Operations Tasks

Note:  
In this section, the command syntax in the task tables displays only the root command; for the complete command syntax, see Command List.

To configure NTP, perform the tasks described in the following sections.

2.1   Configure the NTP Server IP Address

To configure the NTP server IP address, perform the task described in Table 1.

Table 1    Configure the NTP Server IP Address

Task

Root Command

Notes

Configure the SmartEdge router to synchronize to a remote NTP server.

ntp server

Enter this command in global configuration mode.

2.2   Configure NTP Peer Associations (Optional)

To configure NTP peer associations, perform the task described in Table 2.

Table 2    Configure NTP Peer Associations

Task

Root Command

Notes

Configure the peer association for symmetric synchronization of the SmartEdge router time and remote NTP peer time.

ntp peer

Enter this command in global configuration mode.

2.3   Configure Slowsync (Optional)

To configure the SmartEdge router to slowly adjust its local clock rate to compensate for differences with a remote NTP clock source, perform the tasks described in Table 3.

Table 3    Configure Slowsync

Task

Root Command

Notes

Access NTP configuration mode.

ntp mode

Enter this command in global configuration mode.

Configure slowsync.

slowsync

Enter this command in NTP configuration mode.

2.4   Operations Tasks

To monitor, troubleshoot, and administer NTP features, perform the NTP operations tasks described in Table 4. Enter the debug command in exec mode; enter the show commands in any mode.

Table 4    NTP Operations Tasks

Task

Command

Enable the generation of NTP debug messages.

debug ntp

Display the current NTP configuration.

show configuration ntp

Display current associations with remote NTP servers and list daemon statistics for those servers.

show ntp associations

Display current NTP parameter settings and synchronization status.

show ntp status

3   Configuration Examples

The following example shows how to configure the NTP client on the SmartEdge router to synchronize with a remote NTP server at IP address 10.1.1.1:

[local]Redback(config)#ntp server 10.1.1.1

The following commands configure the NTP client on the SmartEdge router to use multiple remote NTP servers as synchronization sources. In this case, the preferred server is at IP address, 20.1.1.1. Symmetric synchronization is also enabled, using the NTP peer with IP address, 155.53.32.75:

[local]Redback#config 

[local]Redback(config)#ntp server 10.1.1.1

[local]Redback(config)#ntp server 20.1.1.1 prefer

[local]Redback(config)#ntp peer 155.53.32.75