Re: [P2PSIP] Alvaro Retana's Discuss on draft-ietf-p2psip-diagnostics-19: (with DISCUSS and COMMENT)
Alissa Cooper <alissa@cooperw.in> Fri, 04 March 2016 19:43 UTC
Return-Path: <alissa@cooperw.in>
X-Original-To: p2psip@ietfa.amsl.com
Delivered-To: p2psip@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 61F671A88C2 for <p2psip@ietfa.amsl.com>; Fri, 4 Mar 2016 11:43:02 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.7
X-Spam-Level:
X-Spam-Status: No, score=-2.7 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001] autolearn=unavailable
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 CT6vs1aJL4XZ for <p2psip@ietfa.amsl.com>; Fri, 4 Mar 2016 11:42:59 -0800 (PST)
Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 8B1F81A88BD for <p2psip@ietf.org>; Fri, 4 Mar 2016 11:42:59 -0800 (PST)
Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id DEC9720A89 for <p2psip@ietf.org>; Fri, 4 Mar 2016 14:36:45 -0500 (EST)
Received: from frontend1 ([10.202.2.160]) by compute6.internal (MEProxy); Fri, 04 Mar 2016 14:36:45 -0500
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=cooperw.in; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to:x-sasl-enc:x-sasl-enc; s=mesmtp; bh=BX+Ef VfgIRiE5ARYnclDDDQXGn4=; b=298vE/lOhynlKIOeoloQ7hAR4aTc4Mdp0ZiqM HoSOVi8WJsf+OAYSGeu6HvDCTd4Y2kOh63+wL3gM0douiCS6RSlrDI3JXUA4Bkt5 G1hUWd0iA8CplcobRY87j3yd47jn7JPufeHIAxr3jGpb4U7ApXqLtXQ91nL3OjSm /7brac=
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-sasl-enc :x-sasl-enc; s=smtpout; bh=BX+EfVfgIRiE5ARYnclDDDQXGn4=; b=qSJFx tpIAZIzVB0ZVK/L7t2mzzbjXYUjYumihgn5lb0BcMrC4wMXLpoRmwQQRVJg5fPJw e/WdFDDCCYzrBKmw5nizQWTJfLoBmUeoF8M9WdE5xqIGZ3F2jq+RunB/md/peIse N1uP8v0IWi0o+j9yhm9jKd1RaOgG/UQmpXlcvU=
X-Sasl-enc: 3XP2uBhUWlYynL8K1cUsGQY8ylOTUmp0cFaEAoOJOSG6 1457120205
Received: from dhcp-171-68-20-44.cisco.com (dhcp-171-68-20-44.cisco.com [171.68.20.44]) by mail.messagingengine.com (Postfix) with ESMTPA id B1784C00018; Fri, 4 Mar 2016 14:36:44 -0500 (EST)
Content-Type: multipart/alternative; boundary="Apple-Mail=_6605EAB1-BFCE-49F0-9F18-59DF81BD3FF6"
Mime-Version: 1.0 (Mac OS X Mail 9.2 \(3112\))
From: Alissa Cooper <alissa@cooperw.in>
In-Reply-To: <D2B42F28.FFE86%aretana@cisco.com>
Date: Fri, 04 Mar 2016 11:36:43 -0800
Message-Id: <AFED0F52-7A79-4F70-819D-D6F385ED6B3A@cooperw.in>
References: <20151216220546.7663.70255.idtracker@ietfa.amsl.com> <E33E01DFD5BEA24B9F3F18671078951F65DAC97F@nkgeml513-mbx.china.huawei.com> <D2B42F28.FFE86%aretana@cisco.com>
To: "Alvaro Retana (aretana)" <aretana@cisco.com>
X-Mailer: Apple Mail (2.3112)
Archived-At: <http://mailarchive.ietf.org/arch/msg/p2psip/JybIWuZOJUaJomB5wtPX6ibDiJ0>
Cc: "p2psip-chairs@ietf.org" <p2psip-chairs@ietf.org>, "p2psip@ietf.org" <p2psip@ietf.org>, IESG <iesg@ietf.org>, "draft-ietf-p2psip-diagnostics@ietf.org" <draft-ietf-p2psip-diagnostics@ietf.org>
Subject: Re: [P2PSIP] Alvaro Retana's Discuss on draft-ietf-p2psip-diagnostics-19: (with DISCUSS and COMMENT)
X-BeenThere: p2psip@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Peer-to-Peer SIP working group discussion list <p2psip.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/p2psip>, <mailto:p2psip-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/p2psip/>
List-Post: <mailto:p2psip@ietf.org>
List-Help: <mailto:p2psip-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/p2psip>, <mailto:p2psip-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 04 Mar 2016 19:43:02 -0000
Hi Alvaro, Are you able to clear based on the latest version? https://tools.ietf.org/html/draft-ietf-p2psip-diagnostics-21 <https://tools.ietf.org/html/draft-ietf-p2psip-diagnostics-21> Thanks, Alissa > On Jan 7, 2016, at 12:27 PM, Alvaro Retana (aretana) <aretana@cisco.com> wrote: > > On 1/6/16, 4:44 AM, "Songhaibin (A)" <haibin.song@huawei.com> wrote: > > Haibin: > > Hi! > > ... >>> >>> >>> >>> ---------------------------------------------------------------------- >>> DISCUSS: >>> ---------------------------------------------------------------------- >>> >>> I am balloting a DISCUSS because I am concerned that this document >>> doesn't >>> actually do what it set out to achieve. I would love it if during the >>> discussion I >>> was pointed to the places where RELOAD already solves the issues, but >>> for now >>> I wasn't able to find them. >>> >>> According to the text, both extensions are intended to collect >>> information >>> "along the path", and the Figures clearly depict what is intended to >>> happen. >>> However, I don't think that as specified (or at least as explained) the >>> behavior is >>> guaranteed. Specific points: >>> >>> 1. RFC6940 says (in Section 6.2. (Symmetric Recursive Routing)) that an >>> "overlay MAY be configured to use alternative routing >>> algorithmsŠ[or]ŠMAY be >>> selected on a per-message basis". How is the symmetry enforced if other >>> routing algorithms are used? Enforcing that the ping/trace messages use >>> symmetric routing when other algorithms are in use won't necessarily >>> help >>> because the paths may be different. >> >> I think one important thing is that, the draft does not guarantee what it >> conveys must be the information that caused the previous failures, but >> with the retrieved information from the previous traversed nodes (with >> high probability, as it cannot guarantee the exact same path), a user or >> machine can analyze and infer what is the problem. Symmetric routing is >> achieved by the via list (whatever DHT routing algorithms are used), but >> response message could go through not exactly the same path as there >> still can be failures during that short period. >> >>> >>> 2. RFC6940 also (in 6.2.2. (Response Origination)) reads: "the response >>> traverses the same peers as the request traversed, except in reverse >>> order >>> (symmetric routing) and possibly with extra nodes (loose routing)." >>> In other words, even if symmetric routing is used, there is no >>> guarantee that >>> the same path will be followed by the response, unless the originator >>> builds the >>> Via List with strict details of all the nodes in the path -- maybe this >>> is what is >>> intended, but no explicit mention occurs in the document. >> >> I agree this should be mentioned in the document. > > Clarifying the caveats (like what we're discussing above, for example) is > one of the ways to move forward with resolving my DISCUSS. > > However, I have to say that the clarifications, which basically point at > no guarantees about the path (or its relevance), leave me very > dissatisfied with a technical solution that is unreliable. :-( > >> >>> >>> 3. In 4.3, what does "directly or via symmetric routing" mean? Is it >>> directly >>> connected? If so, then (for the text in 4.3) that would mean that C is >>> adjacent >>> to A, and even though it is the next hop after B, the path taken to >>> reach C with >>> the PathTrack request doesn't include B ‹ the result is that the >>> diagnostic >>> information received from C may not be relevant relative to destination >>> D. >> >> As each PathTrack request will contain the destination ID, which was the >> same destination ID as the previously failed message. So no matter how >> the PathTrack request arrives to C, C will have a look at that >> destination ID for the next step. > > My point above was the the path *to* C (from A) may not actually even go > through B. In other words, even if the rest of the path (all the way to > D) is congruent, the overall information is still not completely relevant. > >> >> >>> >>> Are there implementations available? What has been the experience? The >>> Shepherd's write-up didn't mention any, and the TBD codes make me think >>> that >>> maybe Experimental might be a better status for this document. >> >> In my memory, there was one several years ago, but not based on RELOAD. > > Given the clear inconsistency and the lack of experience, I want to > suggest that Experimental status be considered. > >> >> >> >>> >>> ---------------------------------------------------------------------- >>> COMMENT: >>> ---------------------------------------------------------------------- >>> >>> In general, as others have mentioned, I think the text could be a lot >>> clearer and >>> not leave some concepts to interpretation. >>> >>> 1. In 4.2.1, the MessageExtension is defined with a Boolean of >>> "critical", but >>> the text (a paragraph later) says that this "extension is not >>> critical". I may be >>> missing some of the semantics, or there's an error somewhere. >> >> My understanding with RELOAD, if value of "critical" can be true or >> false, if it is critical, then every node must support the extension, if >> it is not critical, then it is optional to support it. As it explains in >> that section, "If a peer does not support the extension, they will simply >> ignore the diagnostic portion of the message..." > > I looked at the text again -- it is still confusing to me, but I noticed > that Section 6.1. (Message Creation and Transmission) does say that "the > sender MUST...[set] the value of critical to FALSE". Maybe using > "Critical" (capital C) to describe the state (vs the use of the word as an > adjective) would help. > >> >>> >>> 2. In 4.3..the last paragraph reads: if "...succesive calls to >>> PathTrack return >>> different paths, the results should be discarded and the request resent, >>> ensuring that the second request traverses the appropriate path". >>> Path changes are a fact of life ‹ the second request may just be >>> reflecting the >>> new path, so resending it in an attempt to find the "appropriate path" >>> may be >>> futile. >> >> At least in the previous two attempts, the path was "stable". >> >>> 3. What is a "routing mode"? Section 4.3.1. (New RELOAD Request: >>> PathTrack) talks about it when saying that the "PathTrack request can be >>> routed directly or through the overlay based on the routing mode". >>> Later >>> Section 6.2. (Message Processing: Intermediate Peers) says that >>> "processing >>> this request according to the overlay specified routing mode from RELOAD >>> protocol" -- I looked in RFC6940 for "routing mode", but didn't find >>> anything. >>> Note that it also looks to me like there's no place in the >>> DiagnosticsRequest to >>> indicate a mode.. >> >> This draft should add a reference to RFC 7263 for the routing mode. > > Ok. > >> >>> 4. Section 5.3. (dMFlags and Diagnostic Kind ID Types) defines an >>> "UNDERLAY_HOP (8 bits): Indicates the IP layer hops from the >>> intermediate >>> peer which receives the diagnostics message to the next hop peer for >>> this >>> message." How is that information derived? >> >> It can use the traceroute tool. >> >>> 5. I think that the Reference to RFC5226 should be Normative. >>> >> >> Accepted. >> >>> >>> I also agree with others that the title should probably be something >>> around >>> RELOAD Diagnostics, and that this work doesn't really update RFC6940, it >>> extends it in independent ways. >> >> It seems we can achieve a consensus here that it extends RELOAD. What >> about the title "RELOAD Extension for P2P Overlay Diagnostics"? > > I am not opposed to that. > > Thanks! > > Alvaro. >
- Re: [P2PSIP] Alvaro Retana's Discuss on draft-iet… Songhaibin (A)
- Re: [P2PSIP] Alvaro Retana's Discuss on draft-iet… Songhaibin (A)
- Re: [P2PSIP] Alvaro Retana's Discuss on draft-iet… Alissa Cooper
- Re: [P2PSIP] Alvaro Retana's Discuss on draft-iet… Songhaibin (A)