Juniper JUNOSE 11.3, Configuration Manual

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3.
The system gradually synchronizes its clock to that of the master.
System Operation as an NTP Server
The NTP server supports both unicast (user-to-user addressing protocol) and broadcast
modes. Depending on the server configuration you choose, the system functions in
different ways:
• When the system is configured as a unicast NTP server, it synchronizes clients to its
own clock by responding to NTP requests from clients as follows:
1.
Swaps the destination and source addresses in the request packet.
2.
Sets all timestamps and NTP attributes in the packet.
3.
Returns the packet to the client.
•
When the system is configured as a broadcast NTP server, it periodically sends NTP
time synchronization messages to the local network broadcast address
(255.255.255.255). The broadcast server would also respond to any NTP unicast
requests from clients.
If the system is configured both as an NTP client and an NTP server, the system effectively
synchronizes its clients to its master’s clock. If the system is configured as an NTP server
but not an NTP client, the system synchronizes its clients to its own clock, which can be
set by the
clock commands.
NOTE: When the system is not configured as either an NTP client or an NTP
server, it responds to NTP requests with an invalid stratum number.
Platform Considerations
The system clock is supported on all E Series routers.
For information about the modules supported on E Series routers:
• See the ERX Module Guide for modules supported on ERX7xx models, ERX14xx models,
and the ERX310 Broadband Services Router.
•
See the E120 and E320 Module Guide for modules supported on the E120 and E320
Broadband Services Routers.
References
This implementation of NTP meets the following specifications:
•
RFC 1305—Network Time Protocol (version 3) Specification, Implementation and
Analysis (March 1992)
• RFC 2030—Simple Network Time Protocol (SNTP) (Version 4) for IPv4, IPv6, and OSI
(October 1996)
Copyright © 2010, Juniper Networks, Inc. 510
JunosE 11.3.x System Basics Configuration Guide