Hi Julien,
Thanks for your review on the WSON Impairment Framework draft. On a
high-level, as you mentioned, this is an informational draft that tries to
capture different options for future implementations. In doing so, we have
explored several architectural options in Section 3 and of which PCE option
is a viable option considered as shown in Figure 4 in Section 4.
+-------------------+----+----+----------+--------+
| IA-RWA Option |PCE |Sig |Info Model| Routing|
+-------------------+----+----+----------+--------+
| Combined |Yes | No | Yes | Yes |
| IV & RWA | | | | |
+-------------------+----+----+----------+--------+-
| IV-Candidates |Yes | No | Yes | Yes |
| + RWA | | | | |
+-------------------+----+----+----------+--------+
| Routing + |No | Yes| Yes | No |
|Distributed IV, RWA| | | | |
+-------------------+----+----+----------+--------+
| Detailed IV |Yes | No | Yes | Yes |
+-------------------+----+----+----------+--------+
Figure 4 IA-RWA architectural options and control plane impacts.
This direction is no different from non-impairment RWA architecture, which
PCE WG has accepted as part of its WG item while ago.
However, this does not mean IA-RWA will be automatically assuming PCE as its
solutions. As the non-impairment RWA work has accepted in the PCE WG,
impairment-aware RWA work will need to go through PCE WG's approval process
if the community believes that PCE is a viable implementable option.
Section 4.4 is simply detailing out options depicted in Figure 4 for a clear
understanding. It looks a bit longer compared to other section because there
are several sub-options involved with that. Again, this is simply
informational.
Please see in-line for other comments. Thanks.
Best Regards,
Young
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Julien Meuric
Sent: Saturday, November 20, 2010 12:32 PM
To: [email protected]
Cc: [email protected]
Subject: [CCAMP] WSON Framework with Impairments
Hi CCAMP'ers.
Following the CCAMP meeting in Beijing, I have run a quick check on
draft-ietf-ccamp-wson-impairments-04. As a PCE co-chair, my main concern
is about section 4.4 at large: it explicitly focuses on PCE whereas I am
not sure so much detail is relevant to a CCAMP I-D (even though
informational). What are the plans about this section while moving forward?
YOUNG>> I have discussed in length about this point previously.
Furthermore, here are some comments about some other sections mentioning
PCE or PCEP:
--------------------
Page 8
----------
"Note, the IA path computation may also take place in a separate entity,
i.e., a PCE."
Typo on "i.e.": should be replaced by "e.g." (or else clarification is
required).
YOUNG>> Thanks for pointing out this --- "e.g." seems to be a good
suggestion.
It is not clear what "separate" refers to; proposed rewording:
"computation may also take place in an entity which is different from
the signaling head node, e.g. using PCEP".
YOUNG>> This sounds good to me. Thanks.
--------------------
Page 9
----------
"The authority in control of the "black links" can provide a PCE that
performs full IA-RWA services. The difficulty is this requires the one
authority to also become the sole source of all RWA optimization
algorithms and such."
The phrases "the one authority" and "the sole source" suggest that
uniqueness is assumed, clarification is required.
YOUNG>> I am not sure if I understood what "uniqueness" means. Can you
elaborate this? For this case, we are saying that one authority is
responsible for the control of the "black link" as well as IA-RWA services.
I think this is what you meant "uniqueness" (in the sense of "one" single
authority).
--------------------
Page 13
----------
"if the path computation entity (PCE) [...] if the PCE is given..."
The acronym "PCE" is locally used with a different meaning from what is
defined in the introduction of the document. It seems more appropriate
to write the full phrase "path computation entity" in this section.
YOUNG>> We didn't mean to have a different meaning here than what is used in
the introduction. This should've been simply "PCE".
--------------------
Regards,
Julien
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