Re: [Pce] Clarification Regarding Binding SID in SR-ERO/SRv6-ERO

Hi,

Just to close this on the list as well -- Mrinmoy and I discussed this
offline and the confusion with the BSID in the TLV and the BSID as part of
the SR-ERO subobject is cleared! No further action is needed!

Thanks!
Dhruv

On Wed, May 17, 2023 at 1:02 PM Mrinmoy Das <mrinmoy.ietf@gmail.com> wrote:

> Hello Team,
>
> I was reading
> https://datatracker.ietf.org/doc/draft-ietf-pce-binding-label-sid/16/ and
> find below sections:
>
> 6.  Binding SID in SR-ERO
>
>    In PCEP messages, LSP route information is carried in the Explicit
>    Route Object (ERO), which consists of a sequence of subobjects.
>    [RFC8664] defines the "SR-ERO subobject" capable of carrying a SID as
>    well as the identity of the node/adjacency (NAI) represented by the
>    SID.  The NAI Type (NT) field indicates the type and format of the
>    NAI contained in the SR-ERO.  In case of binding SID, the NAI MUST
>    NOT be included and NT MUST be set to zero.  [RFC8664] Section 5.2.1
>    specifies bit settings and error handling in the case when NT=0.
>
> 7.  Binding SID in SRv6-ERO
>
>    [I-D.ietf-pce-segment-routing-ipv6] defines the "SRv6-ERO subobject"
>    for an SRv6 SID.  Similarly to SR-ERO (Section 6), the NAI MUST NOT
>    be included and the NT MUST be set to zero.  [RFC8664] Section 5.2.1
>    specifies bit settings and error handling in the case when NT=0.
>
>
> Suppose in a SR LSP, there is an ERO object with 3 ero-subobjects, having
> MPLS labels 20, 50, 80.
> Now, this LSP also has 3 binding TLV, having MPLS labels 10, 50, 75.
>
> Now, my questions are:
> 1. Is the restriction mentioned in section 6 means only ERO sub-object
> having MPLS label 50 will not have any NAI as the same label is present as
> Binding value? Other ERO sub-objects having label 20 and 80 can have NAI as
> there is no binding value same to it?
> 2. How does the SID/Label stack look for this LSP in example?
>
> Thanks & Regards,
> Mrinmoy
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