About this task
In addition to selecting the Multicast time synchronization method (Setting the time synchronization method), you must define other Multicast attributes.
To configure additional Multicast time synchronization settings:
Procedure
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In the Time section, modify the attributes listed in Table 1 (Figure 1).
Figure 1. Multicast Time Synchronization Fields
Table 1. Multicast Time Synchronization Fields Attribute
Description
Multicast Group Address
Specifies the IP address used to multicast the SNTP message. This address identifies the group of devices to receive the SNTP message. The RFC-2030 defined standard address is 224.0.1.1. The address is configurable to allow site-specific use.
Multicast UDP Port
Specifies the UDP port on which Multicast time synchronization polls and listens for messages. The RFC-2030 defined standard port is 123.The UDP port defined here must match the Time Server’s UDP port for successful polling to occur.
Multicast TTL
Specifies the Time-to-Live (TTL) for a Multicast message. The value indicates the number of router hops allowed (number of routers to pass through) before the message is not sent. Routers must be configured to pass Multicast messages to allow the time sync message to pass.
Note: A default value of 1 typically stops the Multicast message from leaving the IP subnet of the Site Director. Most routers decrease the existing TTL upon arrival of a packet, and drop the packet instead of rerouting it when the TTL reaches 0.Multicast Heartbeat Interval
Specifies the number of minutes between forcing a Multicast time synchronization message from the Site Director to participating devices.