Dialogic® DSI SS7MD Programmer’s Manual Issue 3

4.9Received Message Timestamping

Timestamping of received messages can be enabled for monitored links. This functionality provides a timestamp of the time a message is received by a board. Individual boards maintain time by synchronising with the host time.

The following table provides details of the expected timestamp accuracy between boards, in a multi board system:

Operating System

Measured Accuracy

 

 

Linux

1 ms

 

 

Solaris

2 ms

 

 

4.9.1Host Configuration

The host must be configured to enable timestamping as follows:

1.Configure the LIU to operate in high-impedance mode using the <liu_type> parameter in the LIU_CONFIG command, which has the following format:

LIU_CONFIG <brd_id> <liu_id> <liu_type> <line_code> <frame_format> <crc_mode>

For example, to configure E1 high-impedance mode, use the command:

LIU_CONFIG 0 0 6 1 1 1

2.Configure receive only monitoring links using the MONITOR_LINK command in the config.txt file, which has the following format:

MONITOR_LINK <link_id> <board_id> <blink> <stream> <timeslot> <user_module> <filter> <flags> <phys_mask>

Timestamping is disabled by default. To enable timestamping on the monitored link, set bit 0 in the <flags> field to 1. For example:

MONITOR_LINK 0 0 0 0 1 0xef 7 0x01 0xff

3.Configure the s7_log utility to display board and/or host timestamp information. See Section 8.1, “s7_log” on page 162 for more information on the command line options for timestamping.

Note: To use the s7_log utility to display timestamps, monitoring messages must be redirected to the s7_log module ID in the MONITOR_LINK command.

4.9.2Timestamp Output

Once timestamping is enabled, a timestamped API_MSG_RX_INDT message is issued by the board instead of an API_MSG_RX_IND message. These messages are sent to the user module configured in the MONITOR_LINK command.

The following are examples of messages without timestamping enabled:

S7L:I0000 M t8f01 i0000 f00 def s00 pffff0103

S7L:I0000 M t8f01 i0000 f00 def s00 pffff0103

The following are examples of messages with timestamping enabled:

S7L:I0000 M t8f0f i0000 f00 def s00 pffff01037caa8ec4e90f2abf

S7L:I0000 M t8f0f i0000 f00 def s00 pffff01037caa8ec4c3976bbf

If the decoding of the timestamps is enabled in the s7_log utility, the output look like the following:

S7L:2001-11-20 15:17:01.012 BRD:2001-11-20 15:17:01.011 I0000 M t7e20 i0000 f0d def s00 p00030001006000

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Dialogic DSI SS7MD manual Host Configuration, Timestamp Output