Cisco 7960G Administrator's Manual page 53

Chapter 3 Initializing Cisco SIP IP Phones
Table 3-4
or when it is assigned a valid IP address.
Table 3-4
SNTP
Server
SNTP server parameter is null
Sends
Receives
SNTP server parameter is a valid IP address.
Sends
Receives
1. If sntp_mode is set to anycast, the sntp_server address will be ignored and subsequent sntp requests will be sent to the first
sntp server that responded (the first sntp request must be unconditionally sent to the broadcast address) .
describes the effects on SNTP mode when the SNTP server is null (not assigned an IP address)
Effects on SNTP Mode
SNTP Mode
Unicast Multicast
No known server SNTP requests are
with which to not sent.
communicate.
No known server Multicast data using
with which to the SNTP/NTP
communicate. multicast address
from the local
network broadcast
address from any
server on the
network.
SNTP request to the SNTP requests are
SNTP server. not sent.
SNTP response from SNTP data via the
the SNTP server and SNTP/NTP multicast
ignores responses address from the
from other SNTP local network
servers. broadcast address.
1
Anycast
SNTP packet to the
local network
broadcast address.
After the first SNTP
response is received,
the phone switches
to unicast mode with
the server being set
as the one who first
responded.
Unicast SNTP data
from the SNTP
server that first
responded to the
network broadcast
request.
If the mode is
anycast and the
SNTP server
parameter is a valid
IP address, the phone
sends the request to
the broadcast address
in version 7.4.
SNTP response from
the SNTP server and
ignores responses
from other SNTP
servers.
Cisco SIP IP Phone Administrator Guide, Release 6.x and 7.x
How to Set the Date and Time
Directed Broadcast
SNTP packet to the
local network
broadcast address.
After the first SNTP
response is received,
the phone switches
to multicast mode.
SNTP data from the
SNTP/NTP multicast
address and the local
network broadcast
address from any
server on the
network.
SNTP packet to the
SNTP server.
After the first SNTP
response is received,
the phone switches
to multicast mode.
SNTP data from the
SNTP/NTP multicast
address and the local
network broadcast
address and ignores
responses from other
SNTP servers.
3-19