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authorOliver Smith <osmith@sysmocom.de>2019-02-01 16:01:55 +0100
committerOliver Smith <osmith@sysmocom.de>2019-02-01 16:05:12 +0100
commit68bbdc5f02d891133123573c422202f61923ebdf (patch)
tree44595be86fbe19e2ffb76aaf98f580d5c48a2ce5
parent2bca846fab0412ccc74d9cb0328d3f374fd71933 (diff)
GSUP: message category indicated by last two bits
Make this part of the specification, so we can simplify libosmocore code by knowing that error message is (request message | 0x000001). Related: I46d9f2327791978710e2f90b4d28a3761d723d8f (libosmocore) Change-Id: Iec1b4ce4b7d8eb157406f006e1c4241e8fba2cd6
-rw-r--r--common/chapters/gsup.adoc13
1 files changed, 13 insertions, 0 deletions
diff --git a/common/chapters/gsup.adoc b/common/chapters/gsup.adoc
index 673ed59..7a16e64 100644
--- a/common/chapters/gsup.adoc
+++ b/common/chapters/gsup.adoc
@@ -766,6 +766,19 @@ Direction: EIR (via HLR) => VLR
|0x32|CHECK-IMEI Result
|===
+The category of the message is indicated by the last two bits of the type.
+Request, Error and Result messages only differ in these last two bits, so it is
+trivial to transform them.
+
+[options="header",cols="20%,80%"]
+|===
+|Ending Bits|Message Category
+|00|Request
+|01|Error
+|10|Result
+|11|Other
+|===
+
[[gsup-ie-ipaddr]]
==== IP Address