9 LTOS7 Management and Monitoring
9.1.5.4 NTP Multicast and Manycast
9.1.5.5 NTP Multicast
NTP Multicast offers the possibility to distribute the time by multicast in the network. The Internet Assigned
Numbers Authority (IANA) has exclusively allocated the multicast IP address 224.0.1.1 for NTP. Therefore, it
is recommended to use this address as a multicast address. However, also other addresses of the multicast
address space can be set.
The multicast address space is as follows:
Ipv4:
224.0.0.0 -> 239.255.255.255
Ipv6:
Every FF00::/8 Address
Multicast Address:
A correct multicast address must be entered here.
Broadcast Interval:
The interval at which the server sends the NTP packets to the
configured broadcast address.
TTL:
The configured TimeToLive (TTL) value determines how many hops NTP packets can
pass in the network. Each network hop reduces this value by 1. When the value
reaches zero, the network packet is dropped.
Symmetric Keys:
For NTP Multicast, an authentication is recommended, but not mandatory.
However, if the authentication is configured on the server side, it is also necessary
to do so on the client side.
In the field "Symmetric Keys" you can therefore enter the ID of a
symmetric key, which is to be used for authentication with the NTP clients.
The following must be respected, to make the authentication work:
a)
The NTP key file of the server must contain the ID. You can edit the key file in the
submenu "NTP
→
NTP Symmetric Keys" on the NTP page.
b)
Additionally you must enter the ID into the field "Trustable Keys" under
"NTP
→
General Settings".
c)
The same key with the same ID must be configured on the NTP client.
LANTIME CPU Expansion Shelf
Date: 2nd July 2020
79
Summary of Contents for LCES
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