Event Structure: Native BOP-SS7

 Event structure What is a BOP event?

Event structure What is a SS7 event?

native BOP display Using the Clarinet Event-Editor without a filter.

SS7 decoding Using the Clarinet Event-Editor with an appropriate filter.

Standards
  • Q703
  

SS7 event

The SS7 events are generated by the analysis process from the SL or DL link when the data structure is based on HDLC frame used by SS7 Protocol.

The SS7 protocol uses the HDLC frame envelope (flag delimitation, CRC,..) but the fill-in between frames of HDLC is achieved by the continuous transmission of fill-in or status frames.

The Clarinet SS7 analysis process includes the following functions:

  • A SS7 event is generated for each:
    • MESSAGE semaphore frame
    • Frame following more than 1 flag
    • Errored frame (CRC, abort, ...)
    • STATE semaphore frame if data has changed
    • FILLING frame if data has changed
  • Counting of the fill-in (FISU/TSR) and status (LSSU/TSE) frames with the same data, and following no more than 1 flag.

The binary event structure is defined in the Clarinet-API.

Clarinet Event-Editor: native BOP display

The edition of the BOP-SS7 events without any decoding/formatting allows the content of different basic fields related to the HDLC frame envelope to be displayed:

ss7_native.gif (10293 octets)

 Event information Date Date of the event (end of BOP frame) in the format: hh:mm:ss/xxx.y  
N The interface number which identifies the Clarinet-interface connected to the host.
Link type
  • TS: Signalling Link Transmit direction
  • RS: Signalling Link Receive direction
  • TD: Data Link Transmit direction
  • RD: Data Link Receive direction
Dx The decoding level as specified in the filter (protocol stack).

Protocol fields BOP <BOP type> <flag counter>    [nnnn]

Data field Field of the conveyed data, displayed in hexadecimal.  

BOP Protocol fields

<BOP type>
  • Frame: Valid frame with correct CRC calculation result.
  • Beginning of Idle state (1 permanent).
  • End of Idle state (1 permanent).
  • Abort frame.
  • Crc error: Frame with false CRC calculation result.

<flag_counter>

 If normal frame, the number of flags from the previous BOP event in the same direction.

[nnnn]

 If normal frame, the number of octets in the information field. The length does not include the 2-octet CRC.

 

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