Re: [Bier] BAR field length in draft-ietf-bier-isis-extensions and draft-ietf-bier-ospf-extensions
Alia Atlas <[email protected]> Wed, 21 Feb 2018 10:09:05 -0500
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--===============0636787364175684317== Content-Type: multipart/alternative; boundary="94eb2c04f602fa32f70565ba4ef4" --94eb2c04f602fa32f70565ba4ef4 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Jeffrey, Yes, I was rushing & may have mangled the terminology in the final bit. The routing layer 8-bit field can be from the IGP Algorithm registry. Thanks for catching it & for your willingness to write this up more clearly= ! Regards, Aka On Feb 21, 2018 10:05 AM, "Jeffrey (Zhaohui) Zhang" <[email protected]> wrote: > Hi Alia, > > > > Thanks for articulating it very clearly, and bring out the issue of havin= g > a clear specification on the interaction. > > > > I need one clarification from you though =E2=80=93 is it possible that th= e you > actually meant BART when you said BARM, and vice versa, in the following? > > > > ------------------ > > With that, the BART can be exactly the IGP Algorithms registry. > > All the IGP Algorithms are available. For the 2 currently defined, the > constraints are empty. > > > > For the BARM, all the necessary constraints can be applied first. > > > > To define a code-point for BARM, the following information is necessary: > > i) Constraints > > ii) Can constraints be additive (default yes unless specified > otherwise) > > iii) What is the algorithm - or is it "empty" > > ------------- > > > > I=E2=80=99ll try to work with Les on the text to specify the interaction. > > > > Jeffrey > > > > *From:* Alia Atlas [mailto:[email protected]] > *Sent:* Wednesday, February 21, 2018 9:45 AM > *To:* Jeffrey (Zhaohui) Zhang <[email protected]> > *Cc:* IJsbrand Wijnands (iwijnand) <[email protected]>; > [email protected] <[email protected]>; > [email protected]; IJsbrand Wijnands <[email protected]>; [email protected]; Eric > Rosen <[email protected]> > *Subject:* Re: [Bier] BAR field length in draft-ietf-bier-isis-extensions > and draft-ietf-bier-ospf-extensions > > > > First, I greatly appreciate the rapid education I have gotten on why the > different aspects of this are important. > > > > Let us explore some details on the plan for an 8-bit BART and an 8-bit > BARM that are independent. Jeffrey, > > I really appreciate your bringing this option to the list. It simplifies > the option B idea of subtypes away and there > > seems to be a good amount of interest in it. > > > > My concern is that we specify adequately how the codepoints in BART and > BARM interact. > > > > One of the challenges with doing so has been, IMHO, a bit of terminology > where we are describing these as > > algorithms but in fact these are tuples consisting of a set of constraint= s > and a base algorithm. > > > > BART is the BIER layer's constraints (BC) and algorithm (BA). Let us > describe this as BART =3D (BC, BA). > > > > BARM is the Routing layer's constraints (RC) and algorithm (RA). Let us > describe this as BARM =3D (RC, RA). > > > > Let me give some concrete examples. > > > > Consider a case of BART=3D4 which is known to mean (prune non-BIER router= s, > use SPF). > > BARM =3D 200, which is known to mean (prune links with BW <10G, use SPF) > > > > It is desirable to have an outcome that is (prune non-BIER routers and > links with BW < 10G, use SPF). > > > > This can work algorithmically because the constraints are the types that > we've seen before for RSVP-TE. > > > > What I think we need to make the independent 8-bit BART plus 8-bit BARM > work is a clear specification > > of the interaction. I think that is: > > > > Start with the topology Topology. > > 1) Apply the constraints represented by the BART BC(Topology) > > 2) Apply the constraints represented by the BARM RC(BC(Topology)) > > 3) Select the algorithm A as follows: use BA or if BA is "empty", use RA= . > > Run A on RC(BC(Topology)) to get the next-hops and information for th= e > BIFT. > > > > Key points on the algorithm aspect are: > > a) BIER is the higher layer, so it is assumed to know better which > algorithm should be used. > > b) It is possible for BA to be "empty" (as the BARM=3D0 case discussed) = so > that the algorithm > > falls through to whatever is RA. > > > > With that, the BART can be exactly the IGP Algorithms registry. > > All the IGP Algorithms are available. For the 2 currently defined, the > constraints are empty. > > > > For the BARM, all the necessary constraints can be applied first. > > > > To define a code-point for BARM, the following information is necessary: > > i) Constraints > > ii) Can constraints be additive (default yes unless specified > otherwise) > > iii) What is the algorithm - or is it "empty" > > > > I am bringing forth this description now because I am concerned that the > interaction between > > BARM and BART is not adequately defined to be published - but I see the > strong interest in > > this as the solution and, from my understanding of the problem, agree. > > > > Please comment ASAP. > > > > Jeffrey & Les, is this something that you can turn into clear text for th= e > drafts? > > > > Regards, > > Alia > > > > > > > > > > On Wed, Feb 21, 2018 at 9:17 AM, Jeffrey (Zhaohui) Zhang < > [email protected]> wrote: > > To make it absolutely clear using an example: even with <BART 1, BARM 200= > > it is still that the two fields are independent of each other. > > This particular combination means =E2=80=9Capply BART 1=E2=80=9D to =E2= =80=9CFlexible-Algo 200=E2=80=9D, > where =E2=80=9CFlexible-Algo 200=E2=80=9D could be =E2=80=9Cexclude red l= inks=E2=80=9D, while =E2=80=9CBART 1=E2=80=9D > could be =E2=80=9Cskip BIER incapable routers=E2=80=9D. > > > > This is a very practical and concrete example showing the advantage of > having two separate fields. Other ways could be used to achieve the same > result, but they=E2=80=99re more cumbersome. > > > > Jeffrey > > > > *From:* BIER [mailto:[email protected]] *On Behalf Of *IJsbrand > Wijnands (iwijnand) > *Sent:* Wednesday, February 21, 2018 8:40 AM > *To:* Jeffrey (Zhaohui) Zhang <[email protected]> > *Cc:* [email protected]; [email protected]; IJsbrand Wijnands <[email protected]>; > [email protected] <[email protected]>; > Eric Rosen <[email protected]> > *Subject:* Re: [Bier] BAR field length in draft-ietf-bier-isis-extensions > and draft-ietf-bier-ospf-extensions > > > > > > > > Ice: No, BART is not being slaved here. If BARM is 0, BART is all yours. > > > > Zzh> BART is BIER=E2=80=99s no matter what BARM is; not only when BARM is= 0. > > > > Ice: Yes, sorry, I agree, BART is always BIER and BARM is always IGP. > > > > Ice: What I meant to clarify is that BART is not slaved to BARM (IGP) and > v.s., if BART is used, BARM will just be 0. > > > > Thx, > > > > Ice. > > > > > > THx, > > > > Ice. > > > > > > Jeffrey > > > > Registry Algorithm a.k.a as BARM then ... Without this section we would b= e > mandating that BARM is always an IGP algorithm or FA so basically it woul= d > mandate IGP > > > > Ice: Yes, BARM will be the IGP algorithm. That is to accommodate the > people on the list who are of the opinion that aligning with IGP is > important. > > > > Algorithm registry as the only option to perform a calculation making BAR= T > possibly pretty much useless ... Having a registry being mapped 1:1 into > another registry known > > > > Ice: I don't understand why you are saying this. If BARM is 0, BART is al= l > yours. Its unfortunate that a large part of the discussion is dominated b= y > perceived functionality in the form of BIER Algorithm, while there is no > architecture draft that describes how it should work and no discussion ha= s > happen in any IETF meeting, which leaves us all guessing. I think Alia > asked a very good question on the list regarding "constraints". It is not > at all clear if BART is a Algorithm or a Constraint. I think from your > response you're saying its both, which seems wrong IMO.. To me Alia's > question is still open, but that that may be because I could not decipher > the rest of your response. > > > > as identity makes them both them the same thing by another name. > > So, to get anywhere close to consensus let's get bit less creative maybe > and stick to the four letters of the alphabet that the AD extended as a > wide playing field and the WG seems to converge around ... Or otherwise > stick to option F) unmodified and see who's > > interested in it unless you insist on creating an option G) ... > > > > Ice: Jeffrey brought option F to the list in order to discuss it, that is > what we are doing, and that is how you can converge on a solution and rea= ch > consensus. That is better compared to a vote on an option and everybody > walks away with a different interpretation of it. > > > > Thx, > > > > Ice. > > > _______________________________________________ > BIER mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/bier > <https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.ietf.org_mail= man_listinfo_bier&d=3DDwMFaQ&c=3DHAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoC= I&r=3Df7wsLGcfzAWDNS6XNTBZwj_OLAOsZZqdrR2IDAzeZqE&m=3D-s4yYMmN1jlRwgyk02_2I= Famu-k7K7di1WiwKt-AoeE&s=3DpJHykwbjl-mkz5oRRkXE6hjOs0tsiC1ucjQtr6-F-4k&e=3D= > > > > --94eb2c04f602fa32f70565ba4ef4 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"auto">Hi Jeffrey,<div dir=3D"auto"><br></div><div dir=3D"auto">= Yes, I was rushing & may have mangled the terminology in the final bit.= </div><div dir=3D"auto"><br></div><div dir=3D"auto">The routing layer 8-bit= field can be from the IGP Algorithm registry.</div><div dir=3D"auto"><br><= /div><div dir=3D"auto">Thanks for catching it & for your willingness to= write this up more clearly!</div><div dir=3D"auto"><br></div><div dir=3D"a= uto">Regards,</div><div dir=3D"auto">Aka</div></div><div class=3D"gmail_ext= ra"><br><div class=3D"gmail_quote">On Feb 21, 2018 10:05 AM, "Jeffrey = (Zhaohui) Zhang" <<a href=3D"mailto:[email protected]">zzhang@juni= per.net</a>> wrote:<br type=3D"attribution"><blockquote class=3D"gmail_q= uote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1e= x"> <div lang=3D"EN-US" link=3D"blue" vlink=3D"purple"> <div class=3D"m_-3435240614789001377WordSection1"> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">Hi Alia,<u></u><u></u></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d"><u></u>=C2=A0<u></u></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">Thanks for articulating it very clear= ly, and bring out the issue of having a clear specification on the interact= ion.<u></u><u></u></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d"><u></u>=C2=A0<u></u></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">I need one clarification from you tho= ugh =E2=80=93 is it possible that the you actually meant BART when you said= BARM, and vice versa, in the following?<u></u><u></u></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d"><u></u>=C2=A0<u></u></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">------------------<u></u><u></u></spa= n></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in">With that, the BART can b= e exactly the IGP Algorithms registry.<u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in">All the IGP Algorithms ar= e available.=C2=A0 =C2=A0For the 2 currently defined, the constraints are e= mpty.<u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><u></u>=C2=A0<u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in">For the BARM, all the nec= essary constraints can be applied first.<u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><u></u>=C2=A0<u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in">To define a code-point fo= r BARM, the following information is necessary:<u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in">=C2=A0 =C2=A0<span class= =3D"m_-3435240614789001377SpellE">i</span>) Constraints<u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in">=C2=A0 =C2=A0ii) Can cons= traints be additive=C2=A0 (default <span class=3D"m_-3435240614789001377SpellE">yes</span> unless specified ot= herwise)<u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in">=C2=A0 =C2=A0iii) What is= the algorithm - or is it "empty"<u></u><u></u></p> <p class=3D"MsoNormal">-------------<u></u><u></u></p> <p class=3D"MsoNormal"><a name=3D"m_-3435240614789001377__MailEndCompose"><= span style=3D"font-size:11.0pt;font-family:"Calibri",sans-serif;c= olor:#1f497d"><u></u>=C2=A0<u></u></span></a></p> <p class=3D"MsoNormal"><span><span style=3D"font-size:11.0pt;font-family:&q= uot;Calibri",sans-serif;color:#1f497d">I=E2=80=99ll try to work with L= es on the text to specify the interaction.<u></u><u></u></span></span></p> <p class=3D"MsoNormal"><span><span style=3D"font-size:11.0pt;font-family:&q= uot;Calibri",sans-serif;color:#1f497d"><u></u>=C2=A0<u></u></span></sp= an></p> <p class=3D"MsoNormal"><span><span style=3D"font-size:11.0pt;font-family:&q= uot;Calibri",sans-serif;color:#1f497d">Jeffrey<u></u><u></u></span></s= pan></p> <p class=3D"MsoNormal"><span><span style=3D"font-size:11.0pt;font-family:&q= uot;Calibri",sans-serif;color:#1f497d"><u></u>=C2=A0<u></u></span></sp= an></p> <span></span> <div style=3D"border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in = 4.0pt"> <div> <div style=3D"border:none;border-top:solid #e1e1e1 1.0pt;padding:3.0pt 0in = 0in 0in"> <p class=3D"MsoNormal"><b><span style=3D"font-size:11.0pt;font-family:"= ;Calibri",sans-serif">From:</span></b><span style=3D"font-size:11.0pt;= font-family:"Calibri",sans-serif"> Alia Atlas [mailto:<a href=3D"mailto:[email protected]" target=3D"_blank">akatl= [email protected]</a>] <br> <b>Sent:</b> Wednesday, February 21, 2018 9:45 AM<br> <b>To:</b> Jeffrey (Zhaohui) Zhang <<a href=3D"mailto:[email protected]= " target=3D"_blank">[email protected]</a>><br> <b>Cc:</b> IJsbrand Wijnands (iwijnand) <<a href=3D"mailto:iwijnand@cisc= o.com" target=3D"_blank">[email protected]</a>>; <a href=3D"mailto:EXT-= [email protected]" target=3D"_blank">EXT-arkadiy.gulko@<wbr>= thomsonreuters.com</a> <<a href=3D"mailto:[email protected]= om" target=3D"_blank">arkadiy.gulko@thomsonreuters.<wbr>com</a>>; <a hre= f=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a>; IJsbrand Wi= jnands <<a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]= </a>>; <a href=3D"mailto:[email protected]" target=3D"_blank">isis-wg@iet= f.org</a>; Eric Rosen <<a href=3D"mailto:[email protected]" target=3D"_= blank">[email protected]</a>><br> <b>Subject:</b> Re: [Bier] BAR field length in draft-ietf-bier-isis-<wbr>ex= tensions and draft-ietf-bier-ospf-<wbr>extensions<u></u><u></u></span></p> </div> </div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> <div> <p class=3D"MsoNormal">First, I greatly appreciate the rapid education I ha= ve gotten on why the different aspects of this are important.<u></u><u></u>= </p> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">Let us explore some details on the plan for an 8-bit= BART and an 8-bit BARM that are independent.=C2=A0 Jeffrey,<u></u><u></u><= /p> </div> <div> <p class=3D"MsoNormal">I really appreciate your bringing this option to the= list.=C2=A0 It simplifies the option B idea of subtypes away and there<u><= /u><u></u></p> </div> <div> <p class=3D"MsoNormal">seems to be a good amount of interest in it.<u></u><= u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">My concern is that we specify adequately how the cod= epoints in BART and BARM interact.=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">One of the challenges with doing so has been, IMHO, = a bit of terminology where we are describing these as<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">algorithms but in fact these are tuples consisting o= f a set of constraints and a base algorithm.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">BART is the BIER layer's constraints (BC) and al= gorithm (BA).=C2=A0 Let us describe this as BART =3D=C2=A0 (BC, BA).<u></u>= <u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">BARM is the Routing layer's constraints (RC) and= algorithm (RA).=C2=A0 Let us describe this as BARM =3D (RC, RA).<u></u><u>= </u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">Let me give some concrete examples.<u></u><u></u></p= > </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">Consider a case of BART=3D4 which is known to mean (= prune non-BIER routers, use SPF).<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">BARM =3D 200, which is known to mean (prune links wi= th BW <10G, use SPF)<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">It is desirable to have an outcome that is (prune no= n-BIER routers and links with BW < 10G, use SPF).<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">This can work algorithmically because the constraint= s are the types that we've seen before for RSVP-TE.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">What I think we need to make the independent 8-bit B= ART plus 8-bit BARM work is a clear specification<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">of the interaction. I think that is:<u></u><u></u></= p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">Start with the topology Topology.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">1) Apply the constraints represented by the BART=C2= =A0 BC(Topology)<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">2) Apply the constraints represented by the BARM=C2= =A0 RC(BC(Topology))<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">3) Select the algorithm A as follows:=C2=A0 use BA o= r if BA is "empty", use RA.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0 =C2=A0 Run A on RC(BC(Topology)) to get the n= ext-hops and information for the BIFT.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">Key points on the algorithm aspect are:<u></u><u></u= ></p> </div> <div> <p class=3D"MsoNormal">a) BIER is the higher layer, so it is assumed to kno= w better which algorithm should be used.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">b) It is possible for BA to be "empty"=C2= =A0 (as the BARM=3D0 case discussed) so that the algorithm<u></u><u></u></p= > </div> <div> <p class=3D"MsoNormal">=C2=A0 =C2=A0 falls through to whatever is RA.<u></u= ><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">With that, the BART can be exactly the IGP Algorithm= s registry.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">All the IGP Algorithms are available.=C2=A0 =C2=A0Fo= r the 2 currently defined, the constraints are empty.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">For the BARM, all the necessary constraints can be a= pplied first.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">To define a code-point for BARM, the following infor= mation is necessary:<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0 =C2=A0i) Constraints<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0 =C2=A0ii) Can constraints be additive=C2=A0 (= default yes unless specified otherwise)<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0 =C2=A0iii) What is the algorithm - or is it &= quot;empty"<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">I am bringing forth this description now because I a= m concerned that the interaction between<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">BARM and BART is not adequately defined to be publis= hed - but I see the strong interest in<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">this as the solution and, from my understanding of t= he problem, agree.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">Please comment ASAP.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">Jeffrey & Les, is this something that you can tu= rn into clear text for the drafts?<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">Regards,<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Alia<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0 =C2=A0=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> </div> <div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> <div> <p class=3D"MsoNormal">On Wed, Feb 21, 2018 at 9:17 AM, Jeffrey (Zhaohui) Z= hang <<a href=3D"mailto:[email protected]" target=3D"_blank">zzhang@jun= iper.net</a>> wrote:<u></u><u></u></p> <blockquote style=3D"border:none;border-left:solid #cccccc 1.0pt;padding:0i= n 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <div> <div> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">To make it absolutely clear using an = example: even with <BART 1, BARM 200> it is still that the two fields are independent of each other.</span><u></u><u></u></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">This particular combination means =E2= =80=9Capply BART 1=E2=80=9D to =E2=80=9CFlexible-<span class=3D"m_-34352406= 14789001377m8474473347374251652spelle">Algo</span> 200=E2=80=9D, where =E2=80=9CFlexible-<span class=3D"m_-343524061478900137= 7m8474473347374251652spelle">Algo</span> 200=E2=80=9D could be =E2=80=9Cexc= lude red links=E2=80=9D, while =E2=80=9CBART 1=E2=80=9D could be =E2=80=9Cs= kip BIER incapable routers=E2=80=9D.</span><u></u><u></u></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">This is a very practical and concrete= example showing the advantage of having two separate fields. Other ways could be used to achieve the same result, but they=E2=80=99re m= ore cumbersome.</span><u></u><u></u></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">Jeffrey</span><u></u><u></u></p> <p class=3D"MsoNormal"><a name=3D"m_-3435240614789001377_m_8474473347374251= 652__MailEndCompose"><span style=3D"font-size:11.0pt;font-family:"Cali= bri",sans-serif;color:#1f497d">=C2=A0</span></a><u></u><u></u></p> <div style=3D"border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in = 4.0pt"> <div> <div style=3D"border:none;border-top:solid #e1e1e1 1.0pt;padding:3.0pt 0in = 0in 0in"> <p class=3D"MsoNormal"> <b><span style=3D"font-size:11.0pt;font-family:"Calibri",sans-ser= if">From:</span></b><span style=3D"font-size:11.0pt;font-family:"Calib= ri",sans-serif"> BIER [mailto:<a href=3D"mailto:[email protected]"= target=3D"_blank">[email protected]</a>] <b>On Behalf Of </b>IJsbrand Wijnands (iwijnand)<br> <b>Sent:</b> Wednesday, February 21, 2018 8:40 AM<br> <b>To:</b> Jeffrey (Zhaohui) Zhang <<a href=3D"mailto:[email protected]= " target=3D"_blank">[email protected]</a>><br> <b>Cc:</b> <a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]= </a>; <a href=3D"mailto:[email protected]" target=3D"_blank"> [email protected]</a>; IJsbrand Wijnands <<a href=3D"mailto:[email protected]= " target=3D"_blank">[email protected]</a>>; <a href=3D"mailto:[email protected]" target=3D"_blank">E= XT-arkadiy.gulko@<wbr>thomsonreuters.com</a> <<a href=3D"mailto:arkadiy.= [email protected]" target=3D"_blank">arkadiy.gulko@thomsonreuters.<w= br>com</a>>; Eric Rosen <<a href=3D"mailto:[email protected]" target= =3D"_blank">[email protected]</a>><br> <b>Subject:</b> Re: [Bier] BAR field length in draft-ietf-bier-isis-<wbr>ex= tensions and draft-ietf-bier-ospf-<wbr>extensions</span><u></u><u></u></p> </div> </div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt"> <blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt"> <div> <div> <div style=3D"border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in = 4.0pt"> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice: No, BART is not being slaved here. If BARM is 0= , BART is all yours.<u></u><u></u></p> </div> <div> <div> <p class=3D"MsoNormal"><span style=3D"color:#1f497d">=C2=A0</span><u></u><u= ></u></p> <p class=3D"MsoNormal"><span class=3D"m_-3435240614789001377m84744733473742= 51652spelle"><span style=3D"font-size:11.0pt;font-family:"Calibri"= ;,sans-serif;color:#1f497d">Zzh</span></span><span style=3D"font-size:11.0p= t;font-family:"Calibri",sans-serif;color:#1f497d">> BART is BIER=E2=80=99s no matter what BARM is; not only when BARM is 0.</s= pan><u></u><u></u></p> </div> </div> </div> </div> </div> </blockquote> <div> <div> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice: Yes, sorry, I agree, BART is always BIER and BA= RM is always IGP.<u></u><u></u></p> </div> </div> </div> </blockquote> <div> <div> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice: What I meant to clarify is that BART is not sla= ved to BARM (IGP) and v.s., if BART is used, BARM will just be 0.<u></u><u>= </u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Thx,<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice.<u></u><u></u></p> </div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><u></u>=C2=A0<u></u><= /p> <blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt"> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">THx,<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice.<u></u><u></u></p> </div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><u></u>=C2=A0<u></u><= /p> <blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt"> <div> <div> <div style=3D"border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in = 4.0pt"> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Ca= libri",sans-serif;color:#1f497d">Jeffrey</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><u></u>=C2=A0<u></u><= /p> <blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt"> <div> <div> <div> <div> <div> <p class=3D"MsoNormal">Registry Algorithm a.k.a as BARM then ... Without th= is section we would be mandating that BARM is always an IGP algorithm or FA= so basically it would mandate IGP <u></u><u></u></p> </div> </div> </div> </div> </div> </blockquote> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice: Yes, BARM will be the IGP algorithm. That is to= accommodate the people on the list who are of the opinion that aligning wi= th IGP is important.=C2=A0<u></u><u></u></p> </div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><u></u>=C2=A0<u></u><= /p> <blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt"> <div> <div> <div> <div> <div> <p class=3D"MsoNormal">Algorithm registry as the only option to perform a c= alculation making BART possibly pretty much useless ... Having a registry b= eing mapped 1:1 into=C2=A0 another registry known <u></u><u></u></p> </div> </div> </div> </div> </div> </blockquote> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice: I don't understand why you are saying this.= If BARM is 0, BART is all yours. Its unfortunate that a large part of the = discussion is dominated by perceived functionality in the form of BIER Algorithm, while there is no architecture draft that desc= ribes how it should work and no discussion has happen in any IETF meeting, = which leaves us all guessing. I think Alia asked a very good question on th= e list regarding "constraints". It is not at all clear if BART is a Algorithm or a Constraint. I think fro= m your response you're saying its both, which seems wrong IMO.. To me A= lia's question is still open, but that that may be because I could not = decipher the rest of your response.<u></u><u></u></p> </div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><u></u>=C2=A0<u></u><= /p> <blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt"> <div> <div> <div> <div> <div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt">as identity makes the= m both them the same thing by another name. <u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">So, to get anywhere close to consensus let's get= bit less creative maybe and stick to the four letters of the alphabet that= the AD extended as a wide playing field and the WG seems to converge around ... Or otherwise stick to option F) unmodified and see = who's<u></u><u></u></p> </div> </div> </div> </div> </div> </blockquote> <blockquote style=3D"margin-top:5.0pt;margin-bottom:5.0pt"> <div> <div> <div> <div> <div> <p class=3D"MsoNormal">interested in it unless you insist on creating an op= tion G) ... <u></u><u></u></p> </div> </div> </div> </div> </div> </blockquote> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice: Jeffrey brought option F to the list in order t= o discuss it, that is what we are doing, and that is how you can converge o= n a solution and reach consensus. That is better compared to a vote on an option and everybody walks away with a different interpret= ation of it.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Thx,<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">=C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal">Ice.<u></u><u></u></p> </div> </div> </div> </div> </blockquote> </blockquote> </div> </div> </div> </div> </div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><br> ______________________________<wbr>_________________<br> BIER mailing list<br> <a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a><br> <a href=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.ietf.= org_mailman_listinfo_bier&d=3DDwMFaQ&c=3DHAkYuh63rsuhr6Scbfh0UjBXeM= K-ndb3voDTXcWzoCI&r=3Df7wsLGcfzAWDNS6XNTBZwj_OLAOsZZqdrR2IDAzeZqE&m= =3D-s4yYMmN1jlRwgyk02_2IFamu-k7K7di1WiwKt-AoeE&s=3DpJHykwbjl-mkz5oRRkXE= 6hjOs0tsiC1ucjQtr6-F-4k&e=3D" target=3D"_blank">https://www.ietf.org/ma= ilman/<wbr>listinfo/bier</a><u></u><u></u></p> </blockquote> </div> <p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p> </div> </div> </div> </div> </blockquote></div></div> --94eb2c04f602fa32f70565ba4ef4-- --===============0636787364175684317== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Isis-wg mailing list [email protected] https://www.ietf.org/mailman/listinfo/isis-wg --===============0636787364175684317==--