Events: ISDN PRI (E1)

Event structure What is ISDN PRI E1 physical event?

PH decoding Using the Clarinet Event-Editor and an appropriate filter.

Protocol stack Defining a list of protocols used in the current filter.

  • ITU Recommendation G703, G704

Options Changing the display conditions in the current filter.

ISDN PRI E1 event decoding

ph_isdn_pri_e1_decod.gif (10628 octets)

Event information Date Date of the event in the format: hh:mm:ss/xxx.y  
N The interface number which identifies the Clarinet-interface connected to the host.
Link type
  • USER: from the user side.
  • NETWORK: from the network side.

Protocol fields Type 1:
ALARM <alarm 1> <alarm 2> ... <alarm n>
or MULTIFRAME <alarm 1> <alarm 2>

The "-+" or "+-" mark indicates the alarm or info_bit state transition.

Type 2:
<error string>

PH-ISDN PRI (E1) Protocol fields

<alarm i>

Alarm or info_bit state evolution in the following format: xydesignation


++ ON state stable (no transition)
-- OFF state stable (no transition)
+- transition from the ON state to the OFF state
-+ transition from the OFF state to the ON state


FL loss of frame alignment PVT in french
ALM alarm indication to the remote end PVTd in french
AIS alarm indication signal (2 Mbits) SIA in french
CRC CRC multi-frame alignment  
AIS64K alarm indication signal (TS 16)  
Sa7 Sa7 bit of TS0  
MFL loss of multi-frame alignment (abcd signalling). PVMT in french
ALM alarm indication to the remote end (abcd signalling) PVMTd in french
  • CRC error (multi-frame CRC4 value)
  • Clock slip

Protocol stack applied

q931_isdn_e1_stack.gif (7440 octets)

Native ISDN PRI (E1) physical event

The ISDN PRI (E1) physical events are generated by the analysis process on the PH link when the physical interface type is based on ISDN PRI (E1 Trunk):

  • Every transition of state of the physical interface (frame alarm, multiframe alarm, info bit) generates an event.
  • Additional events can be generated upon detection of a clock slip or an errored CRC4 value.

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

The edition of the ISDN PRI (E1) physical events without any decoding/formatting enables the successive states of the physical interface to be displayed.


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