Re: [Detnet] Regarding the model for Active OAM packet
Loa Andersson <loa@pi.nu> Fri, 21 September 2018 10:44 UTC
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To: Greg Mirsky <gregimirsky@gmail.com>
Cc: Mach Chen <mach.chen@huawei.com>, DetNet WG <detnet@ietf.org>, János Farkas <Janos.Farkas@ericsson.com>, detnet-chairs@ietf.org, Stewart Bryant <stewart.bryant@gmail.com>, "Bocci, Matthew (Nokia - GB)" <matthew.bocci@nokia.com>
References: <F73A3CB31E8BE34FA1BBE3C8F0CB2AE29267092D@dggeml530-mbs.china.huawei.com> <CA+RyBmX29+Q9y3dXM-PqYm-Nu8KtjYZDs6a-fh_rW5hacSpyRg@mail.gmail.com> <F73A3CB31E8BE34FA1BBE3C8F0CB2AE292672CBB@dggeml530-mbs.china.huawei.com> <d4e45e7d-1001-be64-9ff0-f9ea9a882b77@pi.nu> <F73A3CB31E8BE34FA1BBE3C8F0CB2AE292673B40@dggeml530-mbs.china.huawei.com> <1e141c08-421a-3698-ac5f-02b597d978ea@pi.nu> <CA+RyBmWXMTN0N81QAAQ9jg9=5hKKe7kdrxGyCO8boBMBZfCUqQ@mail.gmail.com>
From: Loa Andersson <loa@pi.nu>
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Date: Fri, 21 Sep 2018 18:44:12 +0800
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Subject: Re: [Detnet] Regarding the model for Active OAM packet
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Greg, On 2018-09-20 20:55, Greg Mirsky wrote: > Hi Loa, > I agree that we can define new ACH Type that will have Sequence Number > immediately following the ACH. OK! > But then we'll need to re-define number > of Types, e.g., BFD, RFC 6374, etc. Or I misunderstood your suggestion.this probably > This probably the key, why do you need to redefine? /Loa > Regards, > Greg > > On Thu, Sep 20, 2018 at 3:13 AM Loa Andersson <loa@pi.nu > <mailto:loa@pi.nu>> wrote: > > Mach, > > I'd like Stewart or Matthew to look at this, but as I understand it it > is possible to define a new ACH-type that can do exactly what you want. > > /Loa > > On 2018-09-20 17:58, Mach Chen wrote: > > Loa, > > > > GAL is just an OAM indicator, the problem here is that when do > DetNet OAM, the d-CW will replaced by ACH or by GAL+ACH. No matter > which way is used, to support the replication or elimination, there > has to be a sequence number filed. But ACH (as its current defined) > does not have such a field. > > > > My suggestion is to use the reserved field of ACH to carry > sequence number of OAM packet, and for those replication or > elimination nodes, they do not have to differentiate whether a > packet is OAM packet or a normal packet, they could just treat the > right 28 bits of the ACH as the sequence number ( or treat the ACH > as the d-CW), then both OAM and replication/elimination can be > supported. > > > > Best regards, > > Mach > > > >> -----Original Message----- > >> From: detnet [mailto:detnet-bounces@ietf.org > <mailto:detnet-bounces@ietf.org>] On Behalf Of Loa Andersson > >> Sent: Thursday, September 20, 2018 3:21 PM > >> To: Mach Chen <mach.chen@huawei.com > <mailto:mach.chen@huawei.com>>; Greg Mirsky > >> <gregimirsky@gmail.com <mailto:gregimirsky@gmail.com>> > >> Cc: DetNet WG <detnet@ietf.org <mailto:detnet@ietf.org>>; János > Farkas > >> <Janos.Farkas@ericsson.com <mailto:Janos.Farkas@ericsson.com>>; > detnet-chairs@ietf.org <mailto:detnet-chairs@ietf.org> > >> Subject: Re: [Detnet] Regarding the model for Active OAM packet > >> > >> Mach, > >> > >> If I understand you correctly this is for an LSP in an MPLS > network, can you > >> help me understand why GAL does not enough. Given that there > might be > >> some minor extensions to GAL because of replication and elimination. > >> > >> /Loa > >> > >> On 2018-09-19 14:31, Mach Chen wrote: > >>> Hi Greg, > >>> > >>> Indeed, there is no DetNet Associated Channel defined in > >>> draft-ietf-detnet-dp-sol-mpls for now, I think there should be. I > >>> also assume that PW ACH will be used for DetNet OAM. > >>> > >>> Assume that PW ACH will be used for DetNet OAM and the reserved > filed > >>> of the PW ACH will be used to carry sequence number for OAM packet. > >>> But > >>> for PREF, a tricky way is to treat the “Version”+ “Reserved” + > >>> ”Channel type” as the Sequence number, the replication or > elimination > >>> nodes do not need to differentiate whether it is a d-CW or a > PW ACH . > >>> This way, OAM can be supported without additional processing > and states. > >>> > >>> 0 1 > 2 3 > >>> > >>> 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 > 7 8 9 0 > >>> 1 > >>> > >>> > >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>> > >>> |0 0 0 1|Verion | Reserved | Channel Type > >>> | > >>> > >>> > >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>> > >>> Regarding sequence number, there are two ways to generate the > >> sequence > >>> number IMHO: 1) generated by the edge node, but it may need to > >>> configure the start number, or 2) copied from the > application-flow (if > >>> there is). If the WG agree with this, the model can be updated > reflect > >>> this. > >>> > >>> Best regards, > >>> > >>> Mach > >>> > >>> *From:*Greg Mirsky [mailto:gregimirsky@gmail.com > <mailto:gregimirsky@gmail.com>] > >>> *Sent:* Wednesday, September 19, 2018 11:29 AM > >>> *To:* Mach Chen <mach.chen@huawei.com > <mailto:mach.chen@huawei.com>> > >>> *Cc:* János Farkas <Janos.Farkas@ericsson.com > <mailto:Janos.Farkas@ericsson.com>>; DetNet WG > >>> <detnet@ietf.org <mailto:detnet@ietf.org>>; > detnet-chairs@ietf.org <mailto:detnet-chairs@ietf.org> > >>> *Subject:* Re: Regarding the model for Active OAM packet > >>> > >>> Hi Mach, > >>> > >>> thank you for your attention to my comment and the most expedient > >> response. > >>> > >>> I don't find the DetNet Associated Channel defined in > >>> draft-ietf-detnet-dp-sol-mpls and thus I assumed that OAM > packets that > >>> follow the data packet encapsulation defined in that draft use > PW ACH > >>> as defined in section 5 RFC 4385: True, it includes 8 bits-long > >>> Reserved field that may be defined as OAM Sequence Number but that > >> had > >>> not been discussed. One is certain, existing nodes do not check the > >>> Reserved field. And without a field to hold the sequence > number, PREF > >>> will not handle the OAM packets. Another question, additional > >>> processing and amount of state introduced in the fast path by > the fact > >>> that OAM's Sequence Number will have different length and > location in > >>> d-CW (differentiating cases by the first nibble). > >>> > >>> Now, if we step back from DetnNet in MPLS data plane encapsulation, > >>> why the control-word, as I understand, is configurable? I think > that > >>> the Sequence Number is not configurable, nor the first nibble. > What do > >>> you think? > >>> > >>> Regards, > >>> > >>> Greg > >>> > >>> On Tue, Sep 18, 2018 at 7:48 PM Mach Chen <mach.chen@huawei.com > <mailto:mach.chen@huawei.com> > >>> <mailto:mach.chen@huawei.com <mailto:mach.chen@huawei.com>>> wrote: > >>> > >>> Hi Greg, > >>> > >>> The MPLS DetNet header is defined as below: > >>> > >>> grouping mpls-detnet-header { > >>> description > >>> "The MPLS DetNet encapsulation header information."; > >>> leaf service-label { > >>> type uint32; > >>> mandatory true; > >>> description > >>> "The service label of the DetNet header."; > >>> } > >>> leaf control-word { > >>> type uint32; > >>> mandatory true; > >>> description > >>> "The control word of the DetNet header."; > >>> } > >>> } > >>> > >>> Although do not consider Active OAM when design the above > >>> mpls-denet-header, seems that it can cover Active OAM > case as well. > >>> No matter a normal DetNet packet or an Active OAM packet, > there > >>> should be a CW field, just as defined above. > >>> > >>> For normal DetNet packets, the CW is the d-CW as defined > in the > >>> draft-ietf-detnet-dp-sol-mpls. > >>> > >>> For OAM packets, the CW is the "DetNet Associated Channel". > >>> > >>> Best regards, > >>> Mach > >>> > >>> > >>> > -----Original Message----- > >>> > From: detnet [mailto:detnet-bounces@ietf.org > <mailto:detnet-bounces@ietf.org> <mailto:detnet- <mailto:detnet-> > >> bounces@ietf.org <mailto:bounces@ietf.org>>] On Behalf > >>> Of Greg Mirsky > >>> > Sent: Wednesday, September 19, 2018 3:17 AM > >>> > To: János Farkas <Janos.Farkas@ericsson.com > <mailto:Janos.Farkas@ericsson.com> > >> <mailto:Janos.Farkas@ericsson.com > <mailto:Janos.Farkas@ericsson.com>>> > >>> > Cc: DetNet WG <detnet@ietf.org <mailto:detnet@ietf.org> > <mailto:detnet@ietf.org <mailto:detnet@ietf.org>>>; detnet- > >> chairs@ietf.org <mailto:chairs@ietf.org> > >>> <mailto:detnet-chairs@ietf.org > <mailto:detnet-chairs@ietf.org>> > >>> > Subject: Re: [Detnet] WG adoption poll > draft-geng-detnet-conf-yang > >>> > > >>> > Hi Janos, et. al, > >>> > the mpls-detnet-header container is based on the > solution described in > >>> > draft-ietf-detnet-dp-sol-mpls. Analysis of active SFC > OAM in the > >> proposed > >>> > MPLS data plane solution in draft-mirsky-detnet-oam > points to the > >> potential > >>> > problem as result the fact that OAM packet doesn't > include d-CW. I > >> believe > >>> > that this question should be discussed and, if we agree > on the problem > >>> > statement, properly resolved. Until then, I do not > support the adoption > >> of > >>> > the model that may not be capable to support active OAM. > >>> > > >>> > Regards, > >>> > Greg > >>> > On Tue, Sep 18, 2018 at 12:03 PM Janos Farkas > >> <Janos.Farkas@ericsson.com <mailto:Janos.Farkas@ericsson.com> > <mailto:Janos.Farkas@ericsson.com <mailto:Janos.Farkas@ericsson.com>>> > >>> > wrote: > >>> > > > >>> > > Dear all, > >>> > > > >>> > > This is start of a two week poll on making > >>> > > draft-geng-detnet-conf-yang-04 a working group > document. Please > >> send > >>> > > email to the list indicating "yes/support" or "no/do > not support". If > >>> > > indicating no, please state your reservations with the > document. If > >>> > > yes, please also feel free to provide comments you'd > like to see > >>> > > addressed once the document is a WG document. > >>> > > > >>> > > The poll ends Oct 3. > >>> > > > >>> > > Thanks, > >>> > > János and Lou > >>> > > > >>> > > _______________________________________________ > >>> > > detnet mailing list > >>> > > detnet@ietf.org <mailto:detnet@ietf.org> > <mailto:detnet@ietf.org <mailto:detnet@ietf.org>> > >>> > > https://www.ietf.org/mailman/listinfo/detnet > >>> > > >>> > _______________________________________________ > >>> > detnet mailing list > >>> > detnet@ietf.org <mailto:detnet@ietf.org> > <mailto:detnet@ietf.org <mailto:detnet@ietf.org>> > >>> > https://www.ietf.org/mailman/listinfo/detnet > >>> > >>> > >>> > >>> _______________________________________________ > >>> detnet mailing list > >>> detnet@ietf.org <mailto:detnet@ietf.org> > >>> https://www.ietf.org/mailman/listinfo/detnet > >>> > >> > >> -- > >> > >> > >> Loa Andersson email: loa@pi.nu > <mailto:loa@pi.nu> > >> Senior MPLS Expert > >> Bronze Dragon Consulting phone: +46 739 81 21 64 > >> > >> _______________________________________________ > >> detnet mailing list > >> detnet@ietf.org <mailto:detnet@ietf.org> > >> https://www.ietf.org/mailman/listinfo/detnet > > _______________________________________________ > > detnet mailing list > > detnet@ietf.org <mailto:detnet@ietf.org> > > https://www.ietf.org/mailman/listinfo/detnet > > > > -- > > > Loa Andersson email: loa@pi.nu <mailto:loa@pi.nu> > Senior MPLS Expert > Bronze Dragon Consulting phone: +46 739 81 21 64 > -- Loa Andersson email: loa@pi.nu Senior MPLS Expert Bronze Dragon Consulting phone: +46 739 81 21 64
- [Detnet] Regarding the model for Active OAM packet Mach Chen
- Re: [Detnet] Regarding the model for Active OAM p… Greg Mirsky
- Re: [Detnet] Regarding the model for Active OAM p… Mach Chen
- Re: [Detnet] Regarding the model for Active OAM p… Loa Andersson
- Re: [Detnet] Regarding the model for Active OAM p… Mach Chen
- Re: [Detnet] Regarding the model for Active OAM p… Loa Andersson
- Re: [Detnet] Regarding the model for Active OAM p… Loa Andersson
- Re: [Detnet] Regarding the model for Active OAM p… Greg Mirsky
- Re: [Detnet] Regarding the model for Active OAM p… Mach Chen
- Re: [Detnet] Regarding the model for Active OAM p… Loa Andersson
- Re: [Detnet] Regarding the model for Active OAM p… Mach Chen
- Re: [Detnet] Regarding the model for Active OAM p… Loa Andersson
- Re: [Detnet] Regarding the model for Active OAM p… Loa Andersson
- Re: [Detnet] Regarding the model for Active OAM p… Greg Mirsky
- Re: [Detnet] Regarding the model for Active OAM p… Greg Mirsky
- Re: [Detnet] Regarding the model for Active OAM p… Loa Andersson
- Re: [Detnet] Regarding the model for Active OAM p… Greg Mirsky
- Re: [Detnet] Regarding the model for Active OAM p… Loa Andersson
- Re: [Detnet] Regarding the model for Active OAM p… Greg Mirsky
- Re: [Detnet] Regarding the model for Active OAM p… Mach Chen