Re: [CCAMP] RFC 4207 LMP Erratum

[Alfred Hönes <ah at TR-Sys.de>]

Vishwas Manral wrote:

> Hi Adrian,
>
> I think the BNF format below is ambiguous as it does not tell which
> part is repeatetive (only trace or others too):
>
>    <TraceMonitor Message> ::= <Common Header> <MESSAGE_ID>
>                               <LOCAL_INTERFACE_ID>
>                               <TRACE> ...

No!
See Section 2.2.5 of RFC 5511, an RFC which expressly was targetted
to codify "existing practice" (so it seems legitimate to apply it):

 2.2.5.  Repetition

   ...

   Meaning:
     May repeat the preceding object, intermediate construct, or
     construct.

   Encoding:
     Three dots ("...").

"<TRACE>" is an intermediate construct; thus it is unambiguously
the item being repeated.


> If we want to be consistent with the other messages in the RFC it should be:
>
>    <TraceMonitor Message> ::= <Common Header> <MESSAGE_ID>
>                               <LOCAL_INTERFACE_ID>
>                               <TRACE> [<TRACE> ...]
>
> However the best representation would be:
>
>    <TraceMonitor Message> ::= <Common Header> <MESSAGE_ID>
>                               <LOCAL_INTERFACE_ID> <TRACE_LIST>
>
>    <TRACE_LIST> ::= <TRACE> [<TRACE_LIST> | ]
>
> Thanks,
> Vishwas
>
> On Fri, Oct 30, 2009 at 2:45 AM, Adrian Farrel <Adrian.Farrel at huawei.com> wrote:
>> Hi CCAMP,
>>
>> Can I please have your help in resolving an Erratum raised against the LMP
>> spec RFC 4207.
>>
>> You can see the full details at
>> http://www.rfc-editor.org/errata_search.php?rfc=4207&eid=167
>>
>> The essence of the question is: how many <TRACE> objects may be present on a
>> <TraceMonitor Message>?
>>
>> The BNF in section 4.1.1 currently implies just one. But the text could be
>> interpreted to man more than one.
>>
>>
>> While you are looking at this, can you say whether any other messages should
>> also allow more than one <TRACE> object?
>>
>> Many thanks,
>> Adrian
>> _______________________________________________
>> CCAMP mailing list
>> CCAMP at ietf.org
>> https://www.ietf.org/mailman/listinfo/ccamp


Kind regards,
  Alfred Hönes.

-- 

+------------------------+--------------------------------------------+
| TR-Sys Alfred Hoenes   |  Alfred Hoenes   Dipl.-Math., Dipl.-Phys.  |
| Gerlinger Strasse 12   |  Phone: (+49)7156/9635-0, Fax: -18         |
| D-71254  Ditzingen     |  E-Mail:  ah at TR-Sys.de                     |
+------------------------+--------------------------------------------+