Dialogic 6.2 用户手册

BSMI Debugging

November 2009

104

The hexadecimal string displayed in the trace consists of the 

following components:

„

Information (I) Frame header

A trace displays hexadecimal strings for I Frame messages 

only. Supervisory (S Frame) messages, such as Receiver Ready 

(RR), and Unnumbered (U Frame) messages, such as SABME 

and UA, are not displayed in hexadecimal format.

„

Message header

„

Information Elements (IEs)

The I Frame header contains Layer 2 routing and packet transaction 

information. The first four bytes of the hexadecimal string comprise 

the I Frame header.

 compares the general format for an I Frame against the I 

Frame for an example SETUP message, and illustrates the following 

points:

„

The trace automatically removes the 0x7E byte flags (binary 

01111110) that normally indicate the start and end of the frame 

and the Frame Check Sequence (FCS) values.

„

A trace automatically interprets and displays I Frame header 

elements such as the SAPI and TEI (refer to 

descriptions of these elements).

„

A value of 0 in the shaded bit position identifies the frame as an 

I Frame.

00C10000 08010105040288901801812C0735353532303030

I Frame

03 278D   Xmit   00  60  0   Setup  00  00  0   0018

Header