Hi,
I have a question about BER encoding of an
octet-string that is 'CONSTRAINED BY' in the following
way.
This is from GSM CAMEL Application Part (CAP)
specification GSM 09.78.
AChBillingChargingCharacteristics ::=
OCTET STRING (SIZE(minAChBillingChargingLength ..
maxAChBillingChargingLength))
(CONSTRAINED BY {-- shall be the result of the
BER-encoded value of the type
CAMEL-AChBillingChargingCharacteristics --})
-- The AChBillingChargingCharacteristics parameter
specifies the charging related information to
-- be provided by the gsmSSF and the conditions on
which this information has to be reported back
-- to the gsmSCF with the ApplyChargingReport
operation. The value of the
-- AchBillingChargingCharacteristics of type OCTET
STRING carries a value of the ASN.1 data type :
-- CAMEL-AchBillingChargingCharacteristics. The
normal encoding rules are used to encode this
-- value.
-- The violation of the UserDefinedConstraint shall
be handled as an ASN.1 syntax error.
CAMEL-AChBillingChargingCharacteristics ::= CHOICE {
timeDurationCharging [0] SEQUENCE {
maxCallPeriodDuration [0] INTEGER
(1..864000),
releaseIfdurationExceeded [1]
ReleaseIfDurationExceeded OPTIONAL,
tariffSwitchInterval [2] INTEGER
(1..86400)
OPTIONAL
}
}
Will the octet-string tag be a constructed tag or will
it remain as primitive.
X.690 section 8.7, says, that octet-strings can have
constructed encoding. But this is for the case where
the octet-string is segmented. Each segment has its
own tag-length-value, where the tag is always 4
(UNIVERSAL OctetString).
I think the encoding should be a, as per X.690, 8.7.
However since the octet-string 'contains' the encoding
of a sequence, it could be considered to be a
constructed encoding.
If anyone has encountered such a scenario and knows
what the right encoding is, please let me know.
Or better still, if anyone has encountered this in GSM
09.78 CAP messages (This is for ApplyCharging and
ApplyCharging CAP messages), please let me know.
Thanks,
Paresh
__________________________________________________
Do you Yahoo!?
Yahoo! Tax Center - File online, calculators, forms, and more
http://tax.yahoo.com
