3gpp2 parameter starts with '\0'

[Bjørn Mork]

Alan DeKok <aland at deployingradius.com> writes:
> lamersons wrote:
>> Thank you very much, changing it to octets gave me nice ascii look of esn.
>> Vendor is Huawei.
>
>   OK.
>
>> to official letter to huawei i got this answer listed below.
>> ----------
>> Good day,
>> 
>>             I would like to inform that our BSC sends ESN according the
>> 3GPP2 “Interoperability Specification (IOS) for cdma2000 Access Network
>> Interfaces — Part 7 (A10 and A11 Interfaces)” (see bellow). BSC sending the
>> ESN refer to the protocol, if the ESN number digit less than 15, should use
>> 0 to fill (8-bit ASCII “0” symbol is /0). 
>> According our analyses, your AAA server does not follow the 3GPP2
>> specification.
>
>   Hmm...  For one, the 3GPP2 documentation appears to disagree with
> itself.  The ESN is clearly stated to be ASCII, as I pointed out.
> Having *another* document state that it contains NUL bytes is just weird.

Yes, it would be.  However, the document Huawei refers to does not state
this.

3GPP2 “Interoperability Specification (IOS) for cdma2000 Access Network
Interfaces — Part 7 (A10 and A11 Interfaces)” (3G-IOS v5.1) from
July 2007, available at
http://www.3gpp2.org/Public_html/specs/A.S0017-D_v1.0_070624.pdf ,
defines the ESN VSA in table 4.2.13-2 "A10 Connection Setup Airlink
Record (Connection Setup)" as

 Parameter Type Sub-Type Max. Payload    Format
                         Length (octet)
 [..]
 ESN       26   52       15              String d,f
 [..]
 d. The string consists of the 8-bit ASCII encoding of the uppercase hexadecimal
    representation of the ESN.
 [..]
 f. Inclusion of ESN, MEID or both parameters in 1 this record is a network operator
    decision.


I don't think footnote d leaves any doubt wrt the format of this
attribute.  The \0 prepending seems to be a Huawei invention. 



Bjørn