draft-ietf-rtgwg-lfa-manageability-07 said "SHOULD" regarding supporting per AF enablement.
draft-ietf-rtgwg-lfa-manageability-08 has changed that to a MAY. In either case an implementation is NOT required to implement this support, so Pushpasis/Hannes - if you don’t want to implement this - then don't. I have zero interest in trying to convince everyone that they MUST implement per AF enablement. My only interest is in making sure that it is not forbidden - and since the draft specifically allows this I am satisfied. Let's move on please. Les > -----Original Message----- > From: rtgwg [mailto:[email protected]] On Behalf Of Pushpasis Sarkar > Sent: Thursday, March 05, 2015 7:28 PM > To: Martin Horneffer; Hannes Gredler > Cc: [email protected] > Subject: Re: LFA manageability : per AF config => feedback required > > Hi Martin, > > I totally agree with the intentions I get from your reply here. I absolutely > support your idea of consuming as less forwarding resource as possible. > But > I also think the intentions will not be met with this kind of Œper AF¹ knob, > simply because we won¹t save any forwarding resources (or even CPU > resources) > if we deploy both AFs under single topology but enable protection for only > one. > So essentially the knob is kind of NO-OP other than not providing protection > for one of the AF. > > Thanks > -Pushpasis > > On 3/5/15, 9:53 PM, "Martin Horneffer" <[email protected]> wrote: > > >Hello Hannes, > > > >sorry for the late response, the flu kept me offline for quite a while. > > > >But sure I can describe my feelings about this. (Pain is about > >feelings, isn't it?) > > > > > >Basically I have learnt during the last decade, that the IGP is better > >kept clean and neat. This is particularly valid for large networks with > >many different services and strict requirements in terms of availabiliy. > >Especially when it comes to forwarding ressources, it's better to > >consume as little ressources as neccessary, so that the those > >forwarding entries that really matter perform best. > > > >One example ist fast IGP convergence: The less FIB entries you have, > >the faster the FIB download works and the faster the IGP convergence is. > > > >Another one ist ECMP vs. IP-FRR. One of our vendors implemented IP-FRR > >in a way that consumes certain ressources that are also used for ECMP. > >Some time after we activated LFA in a certain part of our network, > >operations came back to me saying that now one of 16 available ECMP > >paths was suddenly empty. It turned out that LFA took away one ECMP > >slot and noone had warned me before. > > > > > >Of course, I don't know how your exact implementation of LFA for IPv6 > >in ISIS will behave and whether any of the ressources it consumes would > >actually be critical in my network. > > > >But all in all I'd consider it best to design a network with as little > >consumption of forwardings ressources as possible. And if one address > >family in my IGP would only be used for iBGP, SNMP and ssh, why should > >I protect it with LFA? > > > > > >Best regards, Martin > > > > > >Am 24.02.15 um 18:29 schrieb Hannes Gredler: > >> martin, > >> > >> can you describe what are the pain points of FRR protecting > >> *all* your traffic (IPv4/IPv6/labeled/unlabeled) ? > >> > >> why would you want your traffic not being protected ? > >> > >> /hannes > >> > >> On Tue, Feb 24, 2015 at 05:54:44PM +0100, Martin Horneffer wrote: > >> | Hello everyone, > >> | > >> | I really do see a good use-case for turning on IP-FRR protection > >> | for > >>just > >> | one address family, and it does not have anything to do with making > >>IPv6 > >> | customer better or worse than IPv4 customer traffic. > >> | > >> | Consider the IP/MPLS network I have today. Several address families > >>are > >> | active in the backbone, but all customer traffic is carried in MPLS > >>packets > >> | guided by IPv4-signalled LDP. This holds for ANY customer traffic, > >>whether > >> | it is public IPv4, public IPv6, VPNs in IPv4 or IPv6 or L2-VPNs. > >>Unlabeled > >> | IPv4 traffic also exists in the same backbone, but only for routing > >> | protocols themselves, and/or network management. Thus there is no > >>need to > >> | protect this unlabeled IPv4 traffic in the same way as the customer > >>MPLS > >> | traffic. > >> | > >> | In the future, I might activate IPv6 in the backbone and introduce > >>more and > >> | more routing and management protocols with IPv6. Still no need to > >>protect > >> | IPv6. Eventually I might shift LDP (or SR) from IPv4 controlled to > >>IPv6 > >> | controlled. What was IPv6-over-IPv4-controlled-MPLS becomes plain > >> | IPv6-labeled traffic then, and IPv4-labeled traffic will become > >> | IPv4-over-IPv6-controlled-MPLS. At THAT point in time it becomes > >>important > >> | to protect the IPv6 controlled MPLS traffic, and thus the IPv6 > >> | address family in the IGP, but no earlier. > >> | > >> | So please do not mix up control traffic and customer traffic, > >> | internal routing and customer routes. Thank you. > >> | > >> | Best regards, Martin > >> | > >> | > >> | Am 24.02.15 um 16:02 schrieb Hannes Gredler: > >> | >On Mon, Feb 23, 2015 at 03:55:32PM +0000, Les Ginsberg (ginsberg) > >>wrote: > >> | >| I can imagine cases in which the per AF enabling might make > >>sense (e.g. > >> | >| when the network associated w one address family is deemed > >>non-critical). > >> | > > >> | > > >> | >HG> as it is unlikely that operators will tun off IPv4 protection, > >> | > may i have a ask that you repeat that quote above in the 6man > >> | > meeting ;-) ? - effectifely you're saying "IPv6 may be > >>considered > >> | > as less critical", and therefore we SHOULD provide a knob > >> | > to turn protection off. > >> | > > >> | >| > >> | >| > >> | >| Section 5.1 is a SHOULD - as is most of the document. It is > >>therefore a > >> | >| suggestion as to what an implementation should provide. If a > >>given > >> | >| implementer thinks this is either too onerous or not useful > >>they can omit > >> | >| it w/o being in violation. But I see no reason to eliminate > >>this - and in > >> | >| actual practice I would expect the cost of supporting such a > >>knob to be > >> | >| low cost. It is hard for me to see this as controversial. > >> | >| > >> | >| > >> | >| > >> | >| Les > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| From: [email protected] > >>[mailto:[email protected]] > >> | >| Sent: Sunday, February 22, 2015 11:10 PM > >> | >| To: Les Ginsberg (ginsberg); Pushpasis Sarkar; Jeff Tantsura; > >> | >| [email protected] > >> | >| Subject: RE: LFA manageability : per AF config => feedback > >>required > >> | >| > >> | >| > >> | >| > >> | >| [Les:] I think your point here is that the LFA calculation is AF > >> | >| independent within a given topology - but resources are consumed > >> | >| independent of how many computations are required- giving an > >>operator the > >> | >| ability to determine which prefixes are most critical seems > >>useful. That > >> | >| could be per AF or per prefix. > >> | >| > >> | >| > >> | >| > >> | >| [SLI] Agree but is the "resource saving" point strong enough > >> | >| to > >>mandate > >> | >| per AF activation ? > >> | >| > >> | >| > >> | >| > >> | >| From: Les Ginsberg (ginsberg) [[1]mailto:[email protected]] > >> | >| Sent: Monday, February 23, 2015 05:01 > >> | >| To: Pushpasis Sarkar; Jeff Tantsura; LITKOWSKI Stephane > >>SCE/IBNF; > >> | >| [2][email protected] > >> | >| Subject: RE: LFA manageability : per AF config => feedback > >>required > >> | >| > >> | >| > >> | >| > >> | >| Pushpassis - > >> | >| > >> | >| > >> | >| > >> | >| From: rtgwg [[3]mailto:[email protected]] On Behalf Of > >>Pushpasis > >> | >| Sarkar > >> | >| Sent: Friday, February 20, 2015 3:28 AM > >> | >| To: Jeff Tantsura; [4][email protected]; > >>[5][email protected] > >> | >| Subject: Re: LFA manageability : per AF config => feedback > >>required > >> | >| > >> | >| > >> | >| > >> | >| HI Jeff et al, > >> | >| > >> | >| > >> | >| > >> | >| I can think of a reason to have a knob per-level(or per-area) > >>or per ISIS > >> | >| topology(note in ISIS a topology in ISIS always corresponds > >> | >| to > >>a single > >> | >| AF,) > >> | >| > >> | >| > >> | >| > >> | >| [Les:] This is a common mistake to make. If one simply uses > >> | >| RFC > >>5308, then > >> | >| IPv6 prefixes can be advertised in the same topology as IPv4 > >>(MTID #0) - > >> | >| and there are implementations which support this. More > >>generally, from the > >> | >| protocol's POV a given topology can support any combinations > >> | >| of > >>address > >> | >| families. It is only a convention because of the reserved > >> | >| MTIDs > >>specified > >> | >| in RFC 5120 that certain MTIDs are "IPv6 only". But if one > >>looks at the > >> | >| protocol capabilities such a restriction does not exist in > >>general. > >> | >| > >> | >| > >> | >| > >> | >| Interestingly you contradicted yourself below. J > >> | >| > >> | >| But I did want to set the record straight on this point - > >>hopefully we are > >> | >| in agreement. > >> | >| > >> | >| > >> | >| > >> | >| and per realm and topology in OSPF. But I cannot think of a > >>reason of why > >> | >| within the same topology we need another set of knobs for > >> | >| each > >>AF. Here, > >> | >| by AF I understand IPV4 or IPv6. > >> | >| > >> | >| > >> | >| > >> | >| When both IPV4 and IPV6 are part of the same IGP topology, > >>there is only > >> | >| one set of backup computations needed to protect both IPV4 > >> | >| and > >>IPv6 > >> | >| traffic. > >> | >| > >> | >| > >> | >| > >> | >| Also I cannot think of any motivation for an operator to turn on > >> | >| protection on only one AF and does not want to turn on for > >> | >| the > >>other even > >> | >| if both AFs has been deployed for normal forwarding. > >> | >| > >> | >| > >> | >| > >> | >| [Les:] I think your point here is that the LFA calculation is AF > >> | >| independent within a given topology - but resources are consumed > >> | >| independent of how many computations are required- giving an > >>operator the > >> | >| ability to determine which prefixes are most critical seems > >>useful. That > >> | >| could be per AF or per prefix. > >> | >| > >> | >| > >> | >| > >> | >| Les > >> | >| > >> | >| > >> | >| > >> | >| Thanks > >> | >| > >> | >| -Pushpasis > >> | >| > >> | >| > >> | >| > >> | >| From: Jeff Tantsura <[6][email protected]> > >> | >| Date: Friday, February 20, 2015 at 12:59 PM > >> | >| To: "[7][email protected]" > >><[8][email protected]>, > >> | >| "[9][email protected]" <[10][email protected]> > >> | >| Subject: Re: LFA manageability : per AF config => feedback > >>required > >> | >| > >> | >| > >> | >| > >> | >| Hi Stephane, > >> | >| > >> | >| > >> | >| > >> | >| /chair hat off > >> | >| > >> | >| > >> | >| > >> | >| IMO in disjoined topologies one should have flexibility to > >>enable/disable > >> | >| LFA as per AF. > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| Cheers, > >> | >| > >> | >| Jeff > >> | >| > >> | >| > >> | >| > >> | >| From: "[11][email protected]" > >> | >| <[12][email protected]> > >> | >| Date: Thursday, February 19, 2015 at 11:21 PM > >> | >| To: "[13][email protected]" <[14][email protected]> > >> | >| Subject: LFA manageability : per AF config => feedback > >> | >| required > >> | >| > >> | >| > >> | >| > >> | >| Hi Folks, > >> | >| > >> | >| > >> | >| > >> | >| As you know, LFA manageability draft is in final phasis ... > >> | >| > >> | >| The current document states per AF granularity activation > >> | >| as > >>a SHOULD. > >> | >| > >> | >| " > >> | >| > >> | >| [15]5.1. LFA enabling/disabling scope > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| The granularity of LFA activation should be controlled (as > >>alternate > >> | >| > >> | >| nexthop consume memory in forwarding plane). > >> | >| > >> | >| > >> | >| > >> | >| An implementation of LFA SHOULD allow its activation with > >> | >| the > >> | >| > >> | >| following criteria: > >> | >| > >> | >| > >> | >| > >> | >| o Per address-family : ipv4 unicast, ipv6 unicast, LDP IPv4 > >>unicast, > >> | >| > >> | >| LDP IPv6 unicast ... > >> | >| > >> | >| > >> | >| > >> | >| o Per routing context : VRF, virtual/logical router, global > >>routing > >> | >| > >> | >| table, ... > >> | >| > >> | >| > >> | >| > >> | >| " > >> | >| > >> | >| > >> | >| > >> | >| In the framework of ISIS/OSPF yang modelization, we are > >>challenging this > >> | >| statement, do we really need to force implementation to > >>support this > >> | >| "per AF" granularity ? > >> | >| > >> | >| > >> | >| > >> | >| Please provide as soon as possible your feedback on this > >> | >| and > >>also > >> | >| provide clear drivers to support or not per AF activation > >> | >| of > >>LFA. > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| Thanks for your help ! > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| [16]Orange logo > >> | >| > >> | >| > >> | >| > >> | >| Stephane Litkowski > >> | >| Network Architect > >> | >| Orange/SCE/EQUANT/IBNF/ENDD/NDE > >> | >| > >> | >| Orange Expert Future Networks > >> | >| > >> | >| phone: [17]+33 2 23 28 49 83 > >> | >| mobile: [18]+33 6 37 86 97 52 > >> | >| [19][email protected] > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| > >> | >| > >>________________________________________________________ > ______________ > >>___ ________________________________________________ > >> | >| > >> | >| > >> | >| > >> | >| Ce message et ses pieces jointes peuvent contenir des > >>informations confidentielles ou privilegiees et ne doivent donc > >> | >| > >> | >| pas etre diffuses, exploites ou copies sans autorisation. 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Si > >> | >| vous > >>avez recu ce message par erreur, veuillez le signaler > >> | >| > >> | >| a l'expediteur et le detruire ainsi que les pieces jointes. Les > >>messages electroniques etant susceptibles d'alteration, > >> | >| > >> | >| Orange decline toute responsabilite si ce message a ete altere, > >>deforme ou falsifie. 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