NTP Synchronization

This section provides information about how to set and monitor NTP on your Oracle® Enterprise Session Border Controller.

When an NTP server is unreachable or when NTP service goes down, the Oracle® Enterprise Session Border Controller generates traps for those conditions. Likewise, the Oracle® Enterprise Session Border Controller clears those traps when the conditions have been rectified. The Oracle® Enterprise Session Border Controller considers a configured NTP server to be unreachable when its reach number (whether or not the NTP server could be reached at the last polling interval; successful completion augments the number) is 0. You can see this value for a server when you use the ACLI show ntp server command.

The traps for when a server is unreachable and then again reachable are: apSysMgmtNTPServerUnreachableTrap and apSysMgmtNTPServerUnreachableClearTrap
The traps for when NTP service goes down and then again returns are: apSysMgmtNTPServiceDownTrap and apSysMgmtNTPServiceDownClearTrap

Note:

The Oracle® Enterprise Session Border Controller does not support NTP service over wancom0 when that interface is configured for a VLAN.

Setting NTP Synchronization

When the Oracle® Enterprise Session Border Controller requires time-critical processing, you can set NTP for time synchronization. Setting NTP synchronizes both the hardware and the software clocks with the reference time from an NTP server that you specify. NTP is most useful for synchronizing multiple devices located on one network, or across many networks, to a reference time standard.

To guard against NTP server failure, NTP is restarted periodically to support the dynamic recovery of an NTP server.

Note that ntp-sync works only by way of the management interface and only on wancom0. Do not configure ntp-sync by way of the media interface or any other port.

To set NTP synchronization:

In the ACLI’s configure terminal section, type ntp-sync and then press Enter to access the NTP configuration.
```
ORACLE# configure terminal
ORACLE(configure)# ntp-sync
ORACLE(ntp-config)#
```
To add an NTP server, type add-server, the Space bar, the IPv4 or IPv6 address of the server and then press the Enter key.
For example, this entry adds the NTP server at the Massachusetts Institute of Technology in Cambridge, MA:
```
ORACLE(ntp-config)# add-server 18.26.4.105
```
To delete an NTP server, type delete-server, the Space bar, and the IPv4 or IPv6 address of the server you want to delete and then press the Enter key.
```
ORACLE(ntp-config)# del-server 18.26.4.105
```

Authenticated NTP

The Oracle® Enterprise Session Border Controller can authenticate NTP server requests using MD5. The configured MD5 keys are encrypted and obscured in the ACLI. You configure an authenticated NTP server with its IP address, authentication key, and the key ID. Corresponding key and key IDs are provided by the NTP server administrator.

To configure an authenticated NTP server:

Access the ntp-config configuration element.

ORACLE# configure terminal
ORACLE(configure)# ntp-sync
ACMEPACKET(ntp-config)#

Type select.
```
ORACLE(ntp-config)# select
```

Access the auth-servers configuration element

ORACLE(ntp-config)# auth-servers
ORACLE(auth-servers)#

ip-address — Enter the IPv4 or IPv6 address of the NTP server that supports authentication.
key-id — Enter the key ID of the key you enter in the next step. This value’s range is 1 - 999999999.
key — Enter the key used to secure the NTP requests. The key is a string 1 - 31 characters in length.
Type done to save your work.
Type exit to return to the previous configuration level.
Type done to save the parent configuration element.

Monitoring NTP from the ACLI

NTP server information that you can view with the show ntp server command tell you about the quality of the time being used in terms of offset and delays measurements. You can also see the maximum error bounds.

When you use this command, information for all configured servers is displayed. Data appears in columns that are defined in the table below:

Display Column	Definition
server	Lists the NTP servers configured on the Oracle® Enterprise Session Border Controller by IP address. Entries are accompanied by characters: Plus sign (+)—Symmetric active server Dash (-)—Symmetric passive server Equal sign (=)—Remote server being polled in client mode Caret (^)—Server is broadcasting to this address Tilde (~)—Remote peer is sending broadcast to * Asterisk (*)—The peer to which the server is synchronizing
st	Stratum level—Calculated from the number of computers in the NTP hierarchy to the time reference. The time reference has a fixed value of 0, and all subsequent computers in the hierarchy are n+1.
poll	Maximum interval between successive polling messages sent to the remote host, measured in seconds.
reach	Measurement of successful queries to this server; the value is an 8-bit shift register. A new server starts at 0, and its reach augments for every successful query by shifting one in from the right: 0, 1, 3, 7, 17, 37, 77, 177, 377. A value of 377 means that there have been eight successful queries.
delay	Amount of time a reply packet takes to return to the server (in milliseconds) in response.
offset	Time difference (in milliseconds) between the client’s clock and the server’s.
disp	Difference between two offset samples; error-bound estimate for measuring service quality.

View Statistics

To view statistics for NTP servers:

At the command line, type show ntp server and press Enter.

ORACLE# show ntp server
NTP Status                                    FRI APR 11:09:50 UTC 2007
 server                 st  poll  reach   delay    offset     disp
----------------------- --  ----  ------  -------  --------   ---------
*64.46.24.66             3    64     377  0.00018  0.000329   0.00255
=61.26.45.88             3    64     377  0.00017  0.002122   0.00342

You can the see the status of NTP on your system by using the show ntp status command. Depending on the status of NTP on your system, one of the following messages will appear:

NTP not configured
NTP Daemon synchronized to server at [the IP address of the specific server]
NTP synchronization in process
NTP down, all configured servers are unreachable

View Status

To view the status of NTP on your Oracle® Enterprise Session Border Controller:

At the command line, type show ntp status and press Enter.
```
ORACLE# show ntp status
```