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Re: [IPFIX] Mistake in PSAMP RFCs: Selector ID length

Benoit,

Benoit Claise wrote:

Dear all,

We found a mistake in the PSAMP RFCs.

RFC5477


            8.1.2. selectorId



       Description:

          The Selector ID is the unique ID identifying a Primitive Selector.
          Each Primitive Selector must have a unique ID in the Observation
          Domain.

       Abstract Data Type:  unsigned16                  <------------------

       Data Type Semantics:  identifier

       ElementId:  302

       Status:  current
RFC5476, the selectorID length is 4 bytes in ALL examples (and there are many). 

   IPFIX Options Template Record:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Set ID = 3           |          Length = 26          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Template ID = 262      |         Field Count = 4       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Scope Field Count =  1    |0|  selectionSequenceId = 301  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       Scope 1 Length = 4      |0|     ingressInterface = 10   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Field Length = 4       |0|      selectorId = 302       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Field Length = 4       |0|      selectorId = 302       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Field Length = 4       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The proposed solution is to increase the Selector ID length and put an ERRATA on RFC5477. 16 bits is definitely not enough and clearly not was intended. Since we can do reduced length encoding with larger identifiers, we don't see any harm in making all identifiers 64 bit 

Feedback?


4 Bytes = 32 Bit
You propose to increase it to 64 (=8 Byte), which means that both RFCs need to be corrected. Or is 64 a mistake? 

Regards,
Gerhard



Regards, Benoit.


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Dipl.-Ing. Gerhard Münz
Chair for Network Architectures and Services (I8)
Technische Universität München - Department of Informatics
Boltzmannstr. 3, 85748 Garching bei München, Germany
Phone:  +49 89 289-18008       Fax: +49 89 289-18033
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