3Com 4500 PWR 26-Port Configuration Manual page 649

Multicast mode
Figure 54-5 Multicast mode
Table 54-1 describes how the above mentioned NTP modes are implemented on 3Com S4500 series
Ethernet switches.
Table 54-1 NTP implementation modes on 3Com S4500 series Ethernet switches
NTP implementation mode
Server/client mode
Symmetric peer mode
Broadcast mode
Multicast mode
Configuration on S4500 series switches
Configure the local S4500 Ethernet switch to work in the
NTP client mode. In this mode, the remote server serves
as the local time server, while the local switch serves as
the client.
Configure the local S4500 switch to work in NTP
symmetric peer mode. In this mode, the remote server
serves as the symmetric-passive peer of the S4500
switch, and the local switch serves as the
symmetric-active peer.
Configure the local S4500 Ethernet switch to work in
NTP broadcast server mode. In this mode, the local
switch broadcasts NTP messages through the VLAN
interface configured on the switch.
Configure the S4500 switch to work in NTP broadcast
client mode. In this mode, the local S4500 switch
receives broadcast NTP messages through the VLAN
interface configured on the switch.
Configure the local S4500 Ethernet switch to work in
NTP multicast server mode. In this mode, the local
switch sends multicast NTP messages through the
VLAN interface configured on the switch.
Configure the local S4500 Ethernet switch to work in
NTP multicast client mode. In this mode, the local
switch receives multicast NTP messages through the
VLAN interface configured on the switch.
54-5