Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-extensions-11

[[e-mail]]

Peter, Alvaro

> From: Peter Psenak [mailto:[e-mail]]
> Sent: Thursday, March 11, 2021 11:47 AM

[...]

> > ...
> > 221	4.3.  Maximum H.Encaps MSD Type
> >
> > 223	   The Maximum H.Encaps MSD Type specifies the maximum number
> of SIDs
> > 224	   that can be included as part of the "H.Encaps" behavior as defined
> in
> > 225	   [I-D.ietf-spring-srv6-network-programming].
> >
> > [nit] s/included/pushed   That is the terminology used in rfc8986.
> 
> ##PP
> fixed.
> 
> >
> >
> > ...
> > 229	      If the advertised value is zero or no value is advertised
> > 230	      then the router can apply H.Encaps only by encapsulating
> > 231	      the incoming packet in another IPv6 header without SRH
> > 232	      the same way IPinIP encapsulation is performed.
> >
> > 234	      If the advertised value is non-zero then the router supports both
> > 235	      IPinIP and SRH encapsulation subject to the SID limitation
> > 236	      specified by the advertised value.
> >
> > [major] rfc8986 doesn't talk about IPinIP encapsulation, but is does say this:
> >
> >     The push of the SRH MAY be omitted when the SRv6 Policy only contains
> >     one segment and there is no need to use any flag, tag or TLV.
> >
> > Suggestion (to replace the last two paragraphs)>
> >      If the advertised value is zero or no value is advertised then the
> >      headend can apply an SR Policy that only contains one segment, by
> >      omitting the SRH push.
> >
> >      A non-zero SRH Max H.encaps MSD indicates that the headend can push
> >      an SRH up to the advertised value.
> 
> ##PP
> done, but used "insert" instead of "push".

In SRv6, "Insert" has been used with a different meaning (SRH insertion without IP encapsulation) and hence is very connoted. So I would prefer if we could avoid the term "insert", to avoid both misunderstanding and ambiguities. 

I'm not sure how many/which  :s/push/insert  you are referring to as I'm seen 3  "push". I'll assume you meant the 3 of them. I would suggest the following change, but any other formulation would probably work for me.

OLD: The push of the SRH MAY be omitted
NEW: The SRH MAY be omitted

OLD: by omitting the SRH push.
NEW by omitting the SRH.

OLD: the headend can push an SRH up to the advertised value.
NEW: the headend can perform IP encapsulation with an SRH containing up to MSD SIDs.
(or may be: up to this number of SIDs)



[...]


> 245	      SRH Max End D Type: 45
> 
> 247	      If the advertised value is zero or no value is advertised
> 248	      then it is assumed that the router cannot apply
> 249	      "End.DX6" or "End.DT6" behaviors if the outer IPv6 header
> 250	      contains an SRH.

Since I've started, I'll continue to nick pick.

"assume" does not seem like the right term when talking about an explicit signalling.
I would suggest
OLD: then it is assumed that the router cannot apply
NEW: then the router cannot apply


*3 (in §4.1, §4.2, §4.4)


Thank you,
--Bruno

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