From: Pasi Sarolahti <pasi.sarolahti@iki.fi>
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Date: Tue, 1 Nov 2011 22:09:11 +0200
Message-Id: <FFAE9ADC-5675-4A18-A9AB-CCFB2F317D3C@iki.fi>
To: pcn@ietf.org, draft-ietf-pcn-encoding-comparison@tools.ietf.org
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Cc: tsv-ads@tools.ietf.org, TSV Dir <tsv-dir@ietf.org>
Subject: [PCN] tsv-dir review for draft-ietf-pcn-encoding-comparison-06
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Hello,

I've reviewed this document as part of the transport area directorate's =
ongoing effort to review key IETF documents. These comments were written =
primarily for the transport area directors, but are copied to the =
document's authors for their information and to allow them to address =
any issues raised. The authors should consider this review together with =
any other last-call comments they receive. Please always CC =
tsv-dir@ietf.org if you reply to or forward this review.

Summary: This draft is ready for publication as an Informational RFC =
(but see the editorial suggestions below)


Detailed comments:

* Introduction, para 4: "...design and applicability of PCN-based AC and =
FT." -- AC and FT have not been described (this is only done later, in =
the next section)

* Sec. 2.2.1, para 3: "If the proportion of re-marked (ThM- and ETM-) =
PCN traffic is larger than a CLE-limit..." -- CLE-limit is not =
introduced. It would be good to shortly describe it here, even if it is =
specified in another PCN document.

* Sec. 3.2.2, title: "Tunneling Rules for the Handling of the DSCP" -- =
the wording of the title feels inconvenient. For example, would =
"Tunneling rules for DSCP" be any better (or not)?

* end of sec 3.2.3: "Therefore, option (1) is selected." -- selected for =
what?

* Sec 3.3 -- it might be useful to shortly tell why it is ok to redefine =
ECN bits.

* Sec. 4, para 1: "PCN semantics apply only to one or at most two =
specific DSCPs, and therefore ECN semantics do not apply to them" -- =
this sentence is a bit difficult to parse. Could it be reworded somehow? =
The point is to say that ECN semantics do not apply to PCN DSCPs, or =
what?

* Figure 7 -- Are the PCN-n and PCN-m codepoints specified somewhere? If =
so, add a reference.

* Sec 4.1, para 2: "The 10-codepoint is reserved for experimental =
purposes" -- this is not consistent with table 7, where EXP is on 01 - =
column.

- Pasi