Re: Updated text regarding Mutability in the SRH Draft

Between the rewording for clarity, and the note at the end making clear 
that this effectively makes all those SRH fields mutable, the text i 
snow clear.

While such mutability is not my preference, I can live with it and we 
need to get this done.

Yours,
Joel

On 5/28/19 5:54 PM, Bob Hinden wrote:
> Hello
> 
> Ole and I spent some time reviewing the email on the list and current text in <draft-ietf-6man-segment-routing-header-19.txt>.  We would like to propose the following text in Section 2.
> 
> - - - - -
> 
> OLD:
> 
> In the SRH, the Next Header, Hdr Ext Len, and Routing Type fields are
> defined in Section 4.4 of [RFC8200] as not mutable.  The Segments
> Left field is defined as mutable in Section 4.4 of [RFC8200].
> 
> Some of the other fields of the SRH change en route (i.e. they are
> mutable).  The SRH is processed as defined in Section 4.3 of this
> document, and uniquely per SID type.  The mutability of the remaining
> fields in the SRH (Flags, Tag, Segment List, Optional TLVs) are
> defined in that section, in the context of segment processing.
> 
> NEW:
> 
> In the SRH, the Next Header, Hdr Ext Len, and Routing Type fields are defined in Section 4.4 of [RFC8200] as not mutable.  The Segments Left field is defined as mutable in Section 4.4 of [RFC8200].
> 
> The mutability of the TLV value is defined by the most significant bit in the type, as specified in section 2.1.
> 
> Section 4.3 defines the mutability of the remaining fields in the SRH (Flags, Tag, Segment List) in the context of the SID type defined in this document.
> 
> New SIDs defined in the future MUST specify the mutability properties of the Flags, Tag, and Segment List.  Note, that in effect these fields are mutable.
> 
> - - - - -
> 
> We think this should resolve the open issues regarding defining mutability in SRH.  Please let us know what you think.
> 
> Thanks,
> Bob & Ole
> 
> 
> --------------------------------------------------------------------
> IETF IPv6 working group mailing list
> ipv6@ietf.org
> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
> --------------------------------------------------------------------
> 