Re: [Softwires] Benjamin Kaduk's Discuss on draft-ietf-softwire-yang-14: (with DISCUSS and COMMENT)

<mohamed.boucadair@orange.com> Thu, 10 January 2019 14:08 UTC

Return-Path: <mohamed.boucadair@orange.com>
X-Original-To: softwires@ietfa.amsl.com
Delivered-To: softwires@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 0CC4E1311C6; Thu, 10 Jan 2019 06:08:07 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.599
X-Spam-Level:
X-Spam-Status: No, score=-2.599 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001, UNPARSEABLE_RELAY=0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id e6C0s3tgR3fe; Thu, 10 Jan 2019 06:08:05 -0800 (PST)
Received: from orange.com (mta134.mail.business.static.orange.com [80.12.70.34]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id A24A71311D0; Thu, 10 Jan 2019 06:08:04 -0800 (PST)
Received: from opfednr03.francetelecom.fr (unknown [xx.xx.xx.67]) by opfednr25.francetelecom.fr (ESMTP service) with ESMTP id 43b7BC224QzCsNl; Thu, 10 Jan 2019 15:08:03 +0100 (CET)
Received: from Exchangemail-eme2.itn.ftgroup (unknown [xx.xx.31.66]) by opfednr03.francetelecom.fr (ESMTP service) with ESMTP id 43b7BC0MDZzDq7W; Thu, 10 Jan 2019 15:08:03 +0100 (CET)
Received: from OPEXCLILMA3.corporate.adroot.infra.ftgroup ([fe80::60a9:abc3:86e6:2541]) by OPEXCLILMA1.corporate.adroot.infra.ftgroup ([fe80::95e2:eb4b:3053:fabf%19]) with mapi id 14.03.0415.000; Thu, 10 Jan 2019 15:08:02 +0100
From: <mohamed.boucadair@orange.com>
To: Benjamin Kaduk <kaduk@mit.edu>, The IESG <iesg@ietf.org>
CC: "draft-ietf-softwire-yang@ietf.org" <draft-ietf-softwire-yang@ietf.org>, Sheng Jiang <jiangsheng@huawei.com>, "softwire-chairs@ietf.org" <softwire-chairs@ietf.org>, "jiangsheng@huawei.com" <jiangsheng@huawei.com>, "softwires@ietf.org" <softwires@ietf.org>
Thread-Topic: Benjamin Kaduk's Discuss on draft-ietf-softwire-yang-14: (with DISCUSS and COMMENT)
Thread-Index: AQHUp4m65lo4fw0C906Y69d84ahNh6WohI+w
Date: Thu, 10 Jan 2019 14:08:02 +0000
Message-ID: <787AE7BB302AE849A7480A190F8B93302E0642E0@OPEXCLILMA3.corporate.adroot.infra.ftgroup>
References: <154697630513.25490.16268435481165618838.idtracker@ietfa.amsl.com>
In-Reply-To: <154697630513.25490.16268435481165618838.idtracker@ietfa.amsl.com>
Accept-Language: fr-FR, en-US
Content-Language: fr-FR
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [10.168.234.2]
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
Archived-At: <https://mailarchive.ietf.org/arch/msg/softwires/euW70dh4NEe1qAnyAGURCDtlqf0>
Subject: Re: [Softwires] Benjamin Kaduk's Discuss on draft-ietf-softwire-yang-14: (with DISCUSS and COMMENT)
X-BeenThere: softwires@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: softwires wg discussion list <softwires.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/softwires>, <mailto:softwires-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/softwires/>
List-Post: <mailto:softwires@ietf.org>
List-Help: <mailto:softwires-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/softwires>, <mailto:softwires-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 10 Jan 2019 14:08:09 -0000

Hi Benjamin, 

Thank you for the review. 

Please see inline. 

Cheers,
Med

> -----Message d'origine-----
> De : Benjamin Kaduk [mailto:kaduk@mit.edu]
> Envoyé : mardi 8 janvier 2019 20:38
> À : The IESG
> Cc : draft-ietf-softwire-yang@ietf.org; Sheng Jiang; softwire-
> chairs@ietf.org; jiangsheng@huawei.com; softwires@ietf.org
> Objet : Benjamin Kaduk's Discuss on draft-ietf-softwire-yang-14: (with
> DISCUSS and COMMENT)
> 
> Benjamin Kaduk has entered the following ballot position for
> draft-ietf-softwire-yang-14: Discuss
> 
> When responding, please keep the subject line intact and reply to all
> email addresses included in the To and CC lines. (Feel free to cut this
> introductory paragraph, however.)
> 
> 
> Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
> for more information about IESG DISCUSS and COMMENT positions.
> 
> 
> The document, along with other ballot positions, can be found here:
> https://datatracker.ietf.org/doc/draft-ietf-softwire-yang/
> 
> 
> 
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
> 
> This document has 7 listed authors/editors.  Since, per RFC 7322, documents
> listing more than five authors are unusaul, and seven is greater than five,
> let's talk about the author count.
> 

[Med] Will leave this one to our AD. 


> The binding-table-versioning container's "version" leaf is of type uint64
> but the in-module description indicates that it is a timestamp.  If it is
> actually supposed to be a timestamp, then the units and zero time need to
> be specified, but it seems more likely that this should just be described
> as an abstract version number, if I understand the prose text about this
> container correctly.
> 

[Med] Thank you for catching this one. 

There is a copy/paste bug: 

OLD: 

            container binding-table-versioning {
              description
                "binding table's version";
              leaf version {
                type uint64;
                description
                  "Timestamp when the binding table was activated.

                   A binding instance may be provided with binding
                   entries that may change in time (e.g., increase
                   the size of the port set). When an abuse party
                   presents an external IP address/port, the version
                   of the binding table is important because, depending
                   on the version, a distinct customer may be
                   identified.

                   The timestamp is used as a key to find the
                   appropriate binding table that was put into effect
                   when an abuse occurred. ";
              }
              leaf date {
                type yang:date-and-time;
                description
                  "Timestamp of the binding table";
                reference
                  "RFC7422: Deterministic Address Mapping to Reduce
                            Logging in Carrier-Grade NAT Deployments";
              }
            }


NEW:

            container binding-table-versioning {
              description
                "binding table's version";
              leaf version {
                type uint64;
                description
                  "A version number for the binding table.";
              }
              leaf date {
                type yang:date-and-time;
                description
                  "Timestamp when the binding table was activated.

                   A binding instance may be provided with binding
                   entries that may change in time (e.g., increase
                   the size of the port set). When an abuse party
                   presents an external IP address/port, the version
                   of the binding table is important because, depending
                   on the version, a distinct customer may be
                   identified.

                   The timestamp is used as a key to find the
                   appropriate binding table that was put into effect
                   when an abuse occurred. ";
                reference
                  "RFC7422: Deterministic Address Mapping to Reduce
                            Logging in Carrier-Grade NAT Deployments";
              }
            }

> 
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> Please expand CE on first usage.
> 
> Section 4.1
> 
> It feels a little strange to put something as generic as
> /if:interfaces/if:interface/if:statistics:sent-ipv4-packets in the
> ietf-softwire-ce module.  Are these counters likely to be useful for other
> (non-softwire?) tunneling techniques?

[Med] Some of these counters may be applicable to some other tunneling techniques, but not all of them. As such, these counters cannot be considered as generic. 

If in the future, a YANG module is to be defined for some tunneling technique and similar counters are also applicable fro that technique, that module can use the traffic-stat grouping defined in draft-ietf-softwire-yang. 

> 
> Section 5.2
> 
>    o  softwire-num-max: used to set the maximum number of softwire
>       binding rules that can be created on the lw4o6 element
>       simultaneously.  This paramter must not be set to zero because
>       this is equivalent to disabling the BR instance.
> 
> This seems to leave it ambiguous whether a server should reject an attempt
> to set it to zero, or accept it but diable the BR instance.

[Med] The text is clear, IMO. Furthermore, the range of allowed values is called out explicitly in the module: 

            leaf softwire-num-max {
              type uint32 {
                range "1..max";
              }
...

> 
> Section 7
> 
>             leaf enable-hairpinning {
>               type boolean;
>               default "true";
>               description
>                 "Enables/disables support for locally forwarding
>                  (hairpinning) traffic between two CEs.";
>               reference "Section 6.2 of RFC7596";
> 
> Is a global toggle sufficient or would there be cases where more
> fine-grained control would be needed?
> 

[Med] A+P is designed to reduce as much as possible the per-subscriber state at the network/BR. Requiring fine-grained control would require some extra state to be maintained, which is not desired. Having the general parameter is sufficient.

> Section 8
> 
>     container algo-versioning {
> [...]
>       leaf date {
> 
>         type yang:date-and-time;
>         description
>           "Timestamp when the algorithm instance was activated.
> 
>            An algorithm instance may be provided with mapping
>            rules that may change in time (for example, increase
>            the size of the port set). When an abuse party
>            presents an external IP address/port, the version
>            of the algorithm is important because depending on
>            the version, a distinct customer may be identified.
> 
> nit: "abuse party" is probably not a term that everyone is familiar with.
> (similarly in br-instances)

[Med] We used "abuse" in reference to what is discussed in RFC6269 : https://tools.ietf.org/html/rfc6269#section-13.1. We may add a pointer to that section if you think this is useful. 

> 
> Section 9
> 
> Is there any possibility of a situation where the
> invalid-/added/modified-entry notifications cause a substantial amount of
> notification traffic (i.e., a DoS level of traffic)?
> 

[Med] This is in theory possible if the BR is under the control of a non-authorized/misbehaving entity. The DDoS can be softened by defining a notification interval, but given that this interval parameter can be disabled or set to a low value by the misbehaving entity, the same problem will be observed.