The MPLS WG Archive

[Loa Andersson <loa@pi.se>]

All,

I'd some off-line discussion with Adrian and Seisho on
how to formulate the first sentence of section 4.9.

Adrian came up with the following suggestion:

"Various parameters (such as priority and bandwidth) are associated
with an LSP.
The parameters are installed by the signaling exchanges associated
with establishing and maintaining the LSP."

I had a comment on that the alliteration of various, variant,
variance and variation, made this kind of hard to read and
would suggest a change to:

"Certain parameters (such as priority and bandwidth) are associated
with an LSP.
The parameters are installed by the signaling exchanges associated
with establishing and maintaining the LSP."

/Loa


Seisho Yasukawa wrote:

> Hi MPLS List,
> 
> As promised, this is the first of several emails to resolve the 
> remaining open issues in 
> http://www.ietf.org/internet-drafts/draft-ietf-mpls-p2mp-sig-requirement-00.txt 
> 
> 
> Section 4.9 describes the variation of LSP parameters (e.g. priority, 
> bandwidth, etc.) between different branches of a P2MP LSP. The text 
> currently says
> 
>    Any solution MUST NOT allow for variance of these parameters. That
>    is,
>    - no attributes set and signaled by the ingress of a P2MP LSP may be
>      varied by downstream LSRs
>    - there MUST be homogeneous QoS from the root to all leaves.
> 
> There has been some discussion that it might be desirable to make some 
> variations under the control of the ingress LSR. Also, it has been 
> pointed out that make-before-break is commonly used to vary these 
> parameters.
> 
> We would like to propose to clarify this by changing section 4.9 to read 
> as follows.
> 
> 4.9 Variation of LSP Parameters
> 
>    Various parameters to an LSP (such as priority, bandwidth, etc.) are
>    signaled along each branch of the LSP.
> 
>    Any solution MUST NOT allow for variance of these parameters within a
>    single P2MP LSP. That is:
>    - No attributes set and signaled by the ingress of a P2MP LSP may be
>      varied by downstream LSRs.
>    - There MUST be homogeneous QoS from the root to all leaves of a
>      single P2MP LSP.
> 
>    Variation of parameters may be allowed so long as it applies to the
>    whole LSP from ingress to all egresses.
> 
> 
> If you have comments opposed to this text it would be helpful if you 
> could supply realistic functional requirements that explain how you 
> might deploy anything different.
> 
> Thanks,
> Seisho
> 
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> 
> 

-- 
Loa Andersson

Principal Networking Architect
Acreo AB                           phone:  +46 8 632 77 14
Isafjordsgatan 22                  mobile: +46 739 81 21 64
Kista, Sweden                      email:  loa.andersson@acreo.se
                                            loa@pi.se

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