Subject: Re: [Tsvwg] The suggested code point and intended status of draft-ietf-tsvwg-admitted-realtime-dscp-03

From: Fred Baker <[email-masked]>
Date: Fri, 22 Feb 2008 16:28:09 -0800

Magnus:

You asked about "breaking" RFC 2474. Let me run my reasoning by you.

Thus saith RFC 2474:

> 6.  IANA Considerations
>
>    The DSCP field within the DS field is capable of conveying 64
>    distinct codepoints.  The codepoint space is divided into three  
> pools
>    for the purpose of codepoint assignment and management: a pool  
> of 32
>    RECOMMENDED codepoints (Pool 1) to be assigned by Standards  
> Action as
>    defined in [CONS], a pool of 16 codepoints (Pool 2) to be reserved
>    for experimental or Local Use (EXP/LU) as defined in [CONS], and a
>    pool of 16 codepoints (Pool 3) which are initially available for
>    experimental or local use, but which should be preferentially
>    utilized for standardized assignments if Pool 1 is ever exhausted.
>    The pools are defined in the following table (where 'x' refers to
>    either '0' or '1'):
>
>    Pool        Codepoint space          Assignment Policy
>    ----        ---------------          -----------------
>
>     1            xxxxx0                 Standards Action
>     2            xxxx11                 EXP/LU
>     3            xxxx01                 EXP/LU (*)
>
>    (*) may be utilized for future Standards Action allocations as
>        necessary
>
>    This document assigns eight RECOMMENDED codepoints ('xxx000') which
>    are drawn from Pool 1 above.  These codepoints MUST be mapped,  
> not to
>    specific PHBs, but to PHBs that meet "at least" the requirements  
> set
>    forth in Sec. 4.2.2.2 to provide a minimal level of backwards
>    compatibility with IP Precedence as defined in [RFC791] and as
>    deployed in some current equipment.

Block three is for experimental usages that may be standardized. I  
suggested that we use that block because in my mind the designation  
fitted best. However, if you would prefer I used block 1, I'm  
willing. Flip a coin and advise this weekend while I type away on a  
-04 draft.

Fred

>> Date: Wed, 13 Feb 2008 15:44:35 +0100
>> From: Magnus Westerlund <[email-masked]>
>> User-Agent: Thunderbird 2.0.0.9 (Windows/20071031)
>> To: [email-masked]
>> Cc: [email-masked]
>> Subject: [Tsvwg] The suggested code point and intended status of
>>         draft-ietf-tsvwg-admitted-realtime-dscp-03
>>
>> Hi,
>>
>> I have been reviewing DSCPs for Capacity-Admitted Traffic to see  
>> if was
>> ready for WG last call and have some comments and two interlinked  
>> questions.
>>
>> The draft currently suggests to register code point 101101 which  
>> belongs
>> to pool 3 as defined by RFC 2474. I wonder pool 3 was selected over
>> taking a number in pool 1. Why is 101101 better than for example  
>> 101100?
>>  According to RFC 2474 standards action in pool 3 is for when pool  
>> 1 is
>> exhausted. So please clarify why we should break the RFC 2474
>> recommendations around assignments.
>>
>> Secondly, the draft intended status according to the header is  
>> BCP. The
>> document is also written in that style. My reading of RFC 2474 and  
>> RFC
>> 2434 is that they requires a document registering a new DSCP at  
>> IANA to
>> be STANDARDS TRACK. I think our milestone for this document reflects
>> that when saying that the document is intended to be published as
>> proposed standard. So why has the author tried to target this as a  
>> BCP?
>>
>> I will send the minor details in a separate email.
>>
>> Cheers
>>
>> Magnus Westerlund
>>
>>
>

---

From: Magnus Westerlund <[email-masked]>
Date: Sat, 23 Feb 2008 11:20:40 +0100

Fred Baker skrev:
>>    distinct codepoints.  The codepoint space is divided into three pools
>>    for the purpose of codepoint assignment and management: a pool of 32
>>    RECOMMENDED codepoints (Pool 1) to be assigned by Standards Action as
>>    are drawn from Pool 1 above.  These codepoints MUST be mapped, not to
>>    specific PHBs, but to PHBs that meet "at least" the requirements set
> fitted best. However, if you would prefer I used block 1, I'm willing. 
> Flip a coin and advise this weekend while I type away on a -04 draft.
> 

Fred, can you explain why you think it fits better? I have no deep 
knowledge of diffserv, but to me anything we register are recommended 
code points and should end up in pool 1. I am trying to understand you 
reasoning here. My preference without any further motivation would be to 
use pool 1.

Cheers

Magnus Westerlund

IETF Transport Area Director & TSVWG Chair
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