Subject: [rohc] ROHC MIB update (-09)

From: Juergen Quittek <[email-masked]>
Date: Sun, 04 Jan 2004 05:25:47 +0100

Dear all,

After receiving valuable comments from Bert Wijnen,
I posted a new version of the ROHC MIB.

If you want to have a look at it before it becomes available
in the I-D repository, please have a look at

<ftp://ftp.ccrle.nec.de/pub/internet-drafts/draft-ietf-rohc-mib-rtp-09.txt>.

Below please find the list of changes from version -08 to version -09.
Not listed are 10 fixed typos discovered by Bert.

Happy New Year,

    Juergen
-- 
Juergen Quittek        [email-masked]        Tel: +49 6221 90511-15
NEC Europe Ltd.,       Network Laboratories        Fax: +49 6221 90511-55
Kurfuersten-Anlage 36, 69115 Heidelberg, Germany   http://www.ccrle.nec.de

===============
ROHC MIB Issues
===============

========================================================================
8. Missing DISPLAY-HINT clauses in textual conventions
========================================================================
Problem Description:
------------------------------------------------------------------------
Textual conventions RohcChannelIdentifier and RohcChannelIdentifierOrZero
are missing DISPLAY-HINT clauses.

raised by Mike Heard
========================================================================
Suggested solution:
------------------------------------------------------------------------
add DISPLAY-HIN clause to RohcChannelIdentifier and
RohcChannelIdentifierOrZero

    DISPLAY-HINT "d"
========================================================================
Status: solution committed
========================================================================

========================================================================
9. Range of rohcContextProfile
========================================================================
Problem Description:
------------------------------------------------------------------------
The range of rohcProfile is limited to Unsigned32 (0..65535).
rohcContextProfile can only have values valid for rohcProfile,
but its renge is just Unsigned32.

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
replace SYNTAX clause of rohcContextProfile

  "SYNTAX      Unsigned32"

by

  "SYNTAX      Unsigned32 (0..65535)"
========================================================================
Status: solution committed
========================================================================

========================================================================
10. Relation between rohcProfile and rohcContextProfile
========================================================================
Problem Description:
------------------------------------------------------------------------
For each value of rohcContextProfile there must exist an entry in the
rohcProfileTable that has the same rohcChannelID as first part of the
index and that has rohcProfile with the
rohcChannelStatus), an OID is assingned that is not in line
with the other OIDs assinged to columnar objects of this table.

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
replace DESCRIPTION clause of rohcContextProfile

        "Identifier of the profile for this context.
         The profile is identified by its index in the
         rohcProfileTable for this instance."

by

        "Identifier of the profile for this context.
         The profile is identified by its index in the
         rohcProfileTable for this instance.  There MUST exist a
         corresponding entry in the rohcProfileTable using the
         value of rohcContextProfile as second part of the index
         (and using the same rohcChannelID as first part of the
         index)."
========================================================================
Status: solution committed
========================================================================

========================================================================
11. Avoinding gap in rohcContextTable
========================================================================
Problem Description:
------------------------------------------------------------------------
For object rohcDecompressorDepth in the rohcContextTable, the current
description says that it MUST NOT be instantiated if the entry describes
a compressor context.  An entry describing a compressor context would
have a single gap at the OID of this object.  Dealing with gaps
complicates MIB and manager implementations.

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
replace in DESCRIPTION clause of object rohcContextDecompressorDepth

        "Its value is only valid for decompressor contexts, i.e.
         if rohcInstanceType has the value decompressor(2).  For
         compressor contexts where rohcInstanceType has the value
         compressor(1), this object MUST NOT be instantiated."

by

        "Its value is only valid for decompressor contexts, i.e.
         if rohcInstanceType has the value decompressor(2).  For
         compressor contexts where rohcInstanceType has the value
         compressor(1), the value of this object is irrelavant
         and MUST be set to zero (0)."
========================================================================
Status: solution committed
========================================================================

========================================================================
12. Confusing description of RohcChannelIdentifier
========================================================================
Problem Description:
------------------------------------------------------------------------
The DESCRIPTION clause of textual convention RohcChannelIdentifier calls
0 a reserved value, but the syntax does not allow 0 to be used.

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
replace in DESCRIPTION clauses of textual convention RohcChannelIdentifier

            "The value of 0 is reserved, it must not be
             used as identifier of an existing channel."

by

            "The value of 0 must not be used as identifier
             of an existing channel."
========================================================================
Status: solution committed
========================================================================

========================================================================
13. DESCRIPTION clause of rohcChannelFeedbackFor
========================================================================
Problem Description:
------------------------------------------------------------------------
Incorrect enumeration:
rohcChannelFeedbackFor OBJECT-TYPE
    SYNTAX      RohcChannelIdentifierOrZero
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The index of another channel of this interface for which
         the channel serves as feedback channel.

         If no feedback information is transferred on this channel,
         then the value of this ID is 0. If the channel type is set
==>      to none(1), then the value of this object must be 0.
==>      If the channel type is ROHC(2) and the value of this object
         is a valid channel ID, then feedback information is
         piggy-backed on the ROHC channel."

In the channelType 1 is listed as "notInUse" !!
Would it be better to say MUST instead of "must" ??
And ROHC(2) is listyed as lower case rohc(2) !!
And what if the channelType is 3? is it then such that this object MUST
contain a valid ChannelIdentifier?
For reference:
 rohcChannelType OBJECT-TYPE
     SYNTAX      INTEGER {
                     notInUse(1),
                     rohc(2),
                     dedicatedFeedback(3)
                 }

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
replace second paragraph of DESCRIPTION clause of rohcChannelFeedbackFor

        "If no feedback information is transferred on this channel,
         then the value of this ID is 0. If the channel type is set
         to none(1), then the value of this object must be 0.
         If the channel type is ROHC(2) and the value of this object
         is a valid channel ID, then feedback information is
         piggy-backed on the ROHC channel."

by

        "If no feedback information is transferred on this channel,
         then the value of this ID is 0. If the channel type is set
         to notInUse(1), then the value of this object MUST be 0.
         If the channel type is rohc(2) and the value of this object
         is a valid channel ID, then feedback information is
         piggy-backed on the ROHC channel.  If the channel type is
         dedicatedFeedback(3), then feedback is transferred on this
         channel and the value of this object MUST be different from
         0 and MUST identify an existing ROHC channel."
========================================================================
Status: solution committed
========================================================================

========================================================================
14. persistency of rohcInstanceContextStorageTime
========================================================================
Problem Description:
------------------------------------------------------------------------
rohcInstanceContextStorageTime is a read-write object.
Might be good to say something about expected persistency of a change
made to that object.

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
append to DESCRIPTION clause of rohcInstanceContextStorageTime

     "ROHC-MIB implementations SHOULD store the set value of this
      object persistently."
========================================================================
Status: solution committed
========================================================================

========================================================================
15. What does "respectively" mean in DESCRIPTION clauses?
========================================================================
Problem Description:
------------------------------------------------------------------------
The use of the term "respectively" in the DESCRIPTION clauses of
rohcInstanceIRs, rohcInstanceIRDYNs and rohcInstanceFeedbacks is not
clear.

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
replace in all three DESCRIPTION clauses

     "sent or received, respectively, by this instance"

by

     "that are either sent or received by this instance"
========================================================================
Status: solution committed
========================================================================

========================================================================
16. Terms IR and IRDYN are never explained
========================================================================
Problem Description:
------------------------------------------------------------------------
"IR" and "IRDYN" used in names of objects rohcInstanceIRs and
rohcInstanceIRDYNs are not explained.

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
replace single bullet in section 4.1.2

   "o   the total number of packets passing this instance, and"

by three bullets

   "o   the total number of packets passing this instance

    o   the total number of static Initialization and Refreshs (IRs)
        passing this instance

    o   the total number of dynamic Initialization and Refreshs (IR-
        DYNs) passing this instance, and"

add REFERENCE clause to object rohcInstanceIRs

        "RFC 3095, Section 5.7.7.1"

add REFERENCE clause to object rohcInstanceIRDYNs

        "RFC 3095, Section 5.7.7.2"

add REFERENCE clause to object rohcContextIRs

        "RFC 3095, Section 5.7.7.1"

add REFERENCE clause to object rohcContextIRDYNs

        "RFC 3095, Section 5.7.7.2"
========================================================================
Status: solution committed
========================================================================

========================================================================
17. Textual conventions for Ratios and mean sizes
========================================================================
Problem Description:
------------------------------------------------------------------------
There are four mean size objects and five compression ratio objects.
a few textual conventions might be appropriate.

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
add new TC

   RohcCompressionRatio ::= TEXTUAL-CONVENTION
       DISPLAY-HINT "d"
       STATUS       current
       DESCRIPTION
           "A number indicating a compression ratio over
            a set of bytes.  The value is defined as
            1000 * bytes(compressed) / bytes(original)
            rounded to the next integer value.

            Note that compressed sets of bytes can be larger
            than the corresponding uncompressed ones.
            Therefore, the number can be greater than 1000."
       SYNTAX       Unsigned32

and use it for objects rohcInstanceCompressionRatio,
rohcContextAllPacketsRatio, rohcContextAllHeadersRatio,
rohcContextLastPacketsRatio, rohcContextLastHeadersRatio.

replace DESCRIPTION clause of rohcInstanceCompressionRatio

        "This object indicates the compression ratio so far over all
         packets on the channel served by this instance.  The value
         is defined as 1000 * bytes(compressed) / bytes(original)
         rounded to the next integer value.  The number of bytes
         corresponds to all bytes of all IP packets including the
         IP header but excluding all lower layer headers.

         Note that compressed packets can be larger than the
         corresponding uncompressed ones.  Therefore, this object
         can return values greater than 1000 when it is retrieved."

by

        "This object indicates the compression ratio so far over all
         packets on the channel served by this instance.  The
         compression is computed over all bytes of the IP packets
         including the IP header but excluding all lower layer
         headers."

replace DESCRIPTION clause of rohcContextAllPacketsRatio

        "This object indicates the compression ratio so far over all
         packets passing this context.  The value is defined as
         1000 * bytes(compressed) / bytes(original) rounded to the
         next integer value.  The number of bytes corresponds to all
         bytes of all IP packets including the IP header but
         excluding all lower layer headers.

         Note that compressed packets can be larger than the
         corresponding uncompressed ones.  Therefore, this object
         can return values greater than 1000 when it is retrieved."

by

        "This object indicates the compression ratio so far over all
         packets passing this context.  The compression is computed
         over all bytes of the IP packets including the IP header
         but excluding all lower layer headers."

replace DESCRIPTION clause of rohcContextAllHeadersRatio

        "This object indicates the compression ratio so far over all
         packet headers passing this context.  The value is defined
         as 1000 * bytes(compressed) / bytes(original) rounded to the
         next integer value.  The number of bytes corresponds to all
         bytes of all headers that are subject to compression for the
         used profile.

         Note that compressed headers can be larger than the
         corresponding uncompressed ones.  Therefore, this object
         can return values greater than 1000 when it is retrieved."

by

        "This object indicates the compression ratio so far over all
         packet headers passing this context.  The compression is
         computed over all bytes of all headers that are subject to
         compression for the used profile."

replace DESCRIPTION clause of rohcContextLastPacketsRatio

        "This object indicates the compression ratio
         concerning the last 16 packets passing this context
         or concerning all packets passing this context
         if they are less than 16, so far.  The value is defined
         as 1000 * bytes(compressed) / bytes(original) rounded to
         the next integer value.  The number of bytes corresponds
         to all bytes of the IP packets including the IP
         header but excluding all lower layer headers.

         Note that compressed packets can be larger than the
         corresponding uncompressed ones.  Therefore, this object
         can return values greater than 1000 when it is retrieved."

by

        "This object indicates the compression ratio
         concerning the last 16 packets passing this context
         or concerning all packets passing this context
         if they are less than 16, so far. The compression is
         computed over all bytes of the IP packets including the IP
         header but excluding all lower layer headers."

replace DESCRIPTION clause of rohcContextLastHeadersRatio

        "This object indicates the compression ratio concerning the
         headers of the last 16 packets passing this context or
         concerning the headers of all packets passing this context
         if they are less than 16, so far.  The value is defined as
         1000 * bytes(compressed) / bytes(original) rounded to the
         next integer value.  The number of bytes corresponds to all
         bytes of all headers that are subject to compression for the
         used profile.

         Note that compressed headers can be larger than the
         corresponding uncompressed ones.  Therefore, this object
         can return values greater than 1000 when it is retrieved."

by

        "This object indicates the compression ratio concerning the
         headers of the last 16 packets passing this context or
         concerning the headers of all packets passing this context
         if they are less than 16, so far.  The compression is
         computed over all bytes of all headers that are subject to
         compression for the used profile."
========================================================================
Status: solution committed
========================================================================

========================================================================
18.
========================================================================
Problem Description:
------------------------------------------------------------------------
In rohcRtpContextTable and rohcRtpPacketSizeTable there are several
objects that MUST NOT be instantiated in some cases.
Bert:
 "I again wonder if it would be easier on management apps (possibly
  even agent implementations) to just say that the value must be
  false for rohcProfile values other than 0x0005
  In fact you have a lot of those objects that would NOT be instantiated.
  And I wonder if that is easy. I can live with it though."

raised by Bert Wijnen
========================================================================
Suggested solution:
------------------------------------------------------------------------
no change
========================================================================
Status: no document change required
========================================================================

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---

From: "C. M. Heard" <[email-masked]>
Date: Sun, 11 Jan 2004 00:37:27 -0800 (PST)

> I posted a new version of the ROHC MIB.

I finally got a chance to look at the new version.  The
changes all look good to me.

//cmh

---

From: Allison Mankin <[email-masked]>
Date: Mon, 12 Jan 2004 13:38:47 -0800

Folks,

I've put the ROHC MIB on the 22 January IESG agenda.

Thanks.

Allison