ITEM: V9763L

Why is X.25 session being clear with SNA cause/diagnostic codes?

Question:

Question:

According to the AIX V3 X.25 Communications Cookbook (GG24-4692-01)
cause codes 128 through 255 (hexidecimal 80 through FF) are for SNA.  
I'm running my own application written using the X.25 API -- why
am I seeing SNA cause code 80?


Response:

Cause decimal 128 (hex 80) is the equivalent of cause 0 when the
incoming call is thought to be SNA 1984.  Per the first note on 
pg 76 of the cookbook:

    "The microcode on the X.25 adapter initially assumes that an
     incoming call where the first byte of the Call User Data is 
     greater than 0xC0 is coming from an SNA system.  (All X.25 
     SNA implementations such as QLLC use such codes -- they are
     defined in the architecture manuals.)  Thus, if the adapter 
     does not like the incoming call packet for some reason, it 
     will reject the call using SNA cause and diagnostic codes (See
     E.3 SNA Diagnostic Codes" on page 183.)  SNA codes are only
     assumed until the application is past the incoming call, when 
     it is allowed to specify which codes should be used for the 
     call."



Support Line: Why is X.25 session being clear with SNA cause/diagnostic codes? ITEM: V9763L

Dated: June 1995 Category: N/A

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