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
Содержание Omni Switch/Router
Страница 1: ...Part No 060166 10 Rev C March 2005 Omni Switch Router User Manual Release 4 5 www alcatel com ...
Страница 4: ...page iv ...
Страница 110: ...WAN Modules Page 3 40 ...
Страница 156: ...UI Table Filtering Using Search and Filter Commands Page 4 46 ...
Страница 164: ...Using ZMODEM Page 5 8 ...
Страница 186: ...Displaying and Setting the Swap State Page 6 22 ...
Страница 202: ...Creating a New File System Page 7 16 ...
Страница 270: ...Displaying Secure Access Entries in the MPM Log Page 10 14 ...
Страница 430: ...OmniChannel Page 15 16 ...
Страница 496: ...Configuring Source Route to Transparent Bridging Page 17 48 ...
Страница 542: ...Dissimilar LAN Switching Capabilities Page 18 46 ...
Страница 646: ...Application Example DHCP Policies Page 20 30 ...
Страница 660: ...GMAP Page 21 14 ...
Страница 710: ...Viewing the Virtual Interface of Multicast VLANs Page 23 16 ...
Страница 722: ...Application Example 5 Page 24 12 ...
Страница 788: ...Viewing UDP Relay Statistics Page 26 24 ...
Страница 872: ...The WAN Port Software Menu Page 28 46 ...
Страница 960: ...Deleting a PPP Entity Page 30 22 ...
Страница 978: ...Displaying Link Status Page 31 18 ...
Страница 988: ...Displaying ISDN Configuration Entry Status Page 32 10 ...
Страница 1024: ...Backup Services Commands Page 34 14 ...
Страница 1062: ...Diagnostic Test Cable Schematics Page 36 24 ...
Страница 1072: ...Configuring a Switch with an MPX Page A 10 ...
Страница 1086: ...Page B 14 ...
Страница 1100: ...Page I 14 Index ...