HI,

I agree with Juergen. You should be seeing that object snmpInASNParseErrs
is incremented when you send a negative value for msgMaxSize.

BER uses different rules for encoding lengths, integer values, 
and the values of sub-IDs of an OID.

Regards,
/david t. perkins

On Mon, 4 Feb 2008, Chun Tian (binghe) wrote:
> Hi, J.S.
>
> Ah... 0xffe3 will be treat as a minus integer... And by recheck ISO/
> IEC 8825-1:2003 (E) (BER encoding), I find this:
>
> 8.3.2 If the contents octets of an integer value encoding consist of
> more than one octet, then the bits of the first octet and bit 8 of the
> second octet:
> a) shall not all be ones; and
> b) shall not all be zero.
> NOTE ? These rules ensure that an integer value is always encoded in
> the smallest possible number of octets.
>
> So this is mistake in my BER encode function for integer.
>
> Sorry for disturbing this mail list.
>
> Regards,
> Chun TIAN (binghe)
>
> On Feb 4, 2008, at 12:08 PM, Juergen Schoenwaelder wrote:
>
>> On Sun, Feb 03, 2008 at 11:07:28PM +0000, Dave Shield wrote:
>>
>>>> What I don't know is why this value must be encoded to a 3-bytes
>>>> integer,
>>>> not 2-bytes, just like this:
>>>>
>>>> 0x02, 0x02, 0xff, 0xe3
>>>
>>> Because the BER encoding does *not* use 8-bit values.
>>> It uses 7-bit values plus a continuation bit.
>>> The top-most bit of the first octet of an integer value must
>>> *ALWAYS* be 0.
>>
>> You both get it wrong. The 0x00 byte is required since the value is a
>> signed integer.
>>
>> /js
>>
>> --
>> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
>> Phone: +49 421 200 3587         Campus Ring 1, 28759 Bremen, Germany
>> Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>
>
>
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