Page 12-3
Servers 1a and 1b receive time information from, or synchronize with, a
UTC
time source such
as a radio clock. (In most cases, these servers would not be connected to the same
UTC
source, though it is shown this way for simplicity.) Servers 1a and 1b become stratum 1
NTP
servers and are peered with each other, allowing them to check
UTC
time information against
each other. These machines support machines 2a and 2b as clients, and these clients are
synchronized to the higher stratum servers 1a and 1b.
Clients 2a and 2b are also peered with each other for time checks, and become stratum 2
NTP
servers for more clients (3a and 3b, which are also peered).
In this hierarchy, the stratum 1 servers synchronize to the most accurate time source avail-
able, then check the time information with peers at the same stratum. The stratum 2 machines
synchronize to the stratum 1 servers, but do not send time information to the stratum 1
machines. Machines 2a and 2b in turn provide time information to the stratum 3 machines.
It is important to consider the issue of robustness when selecting sources for time synchroni-
zation. It is suggested that at least three sources should be available, and at least one should
be “close” to you in terms of network topology. It is also suggested that each
NTP
client is
peered with at least three other same stratum clients, so that time information crosschecking
will be performed.
Time Source
(UTC)
Stratum 1
Peer Association
Peer Association
Stratum 2
Client/
NTP
Peer Association
NTP
Clients
Stratum 3
1b
2a
2b
3a
3b
1a
Servers
NTP
Servers
Summary of Contents for Omni Switch/Router
Page 1: ...Part No 060166 10 Rev C March 2005 Omni Switch Router User Manual Release 4 5 www alcatel com ...
Page 4: ...page iv ...
Page 110: ...WAN Modules Page 3 40 ...
Page 156: ...UI Table Filtering Using Search and Filter Commands Page 4 46 ...
Page 164: ...Using ZMODEM Page 5 8 ...
Page 186: ...Displaying and Setting the Swap State Page 6 22 ...
Page 202: ...Creating a New File System Page 7 16 ...
Page 270: ...Displaying Secure Access Entries in the MPM Log Page 10 14 ...
Page 430: ...OmniChannel Page 15 16 ...
Page 496: ...Configuring Source Route to Transparent Bridging Page 17 48 ...
Page 542: ...Dissimilar LAN Switching Capabilities Page 18 46 ...
Page 646: ...Application Example DHCP Policies Page 20 30 ...
Page 660: ...GMAP Page 21 14 ...
Page 710: ...Viewing the Virtual Interface of Multicast VLANs Page 23 16 ...
Page 722: ...Application Example 5 Page 24 12 ...
Page 788: ...Viewing UDP Relay Statistics Page 26 24 ...
Page 872: ...The WAN Port Software Menu Page 28 46 ...
Page 960: ...Deleting a PPP Entity Page 30 22 ...
Page 978: ...Displaying Link Status Page 31 18 ...
Page 988: ...Displaying ISDN Configuration Entry Status Page 32 10 ...
Page 1024: ...Backup Services Commands Page 34 14 ...
Page 1062: ...Diagnostic Test Cable Schematics Page 36 24 ...
Page 1072: ...Configuring a Switch with an MPX Page A 10 ...
Page 1086: ...Page B 14 ...
Page 1100: ...Page I 14 Index ...