Thomas, I completely agree w/ your email, below.
Yours Irrespectively, John > -----Original Message----- > From: BESS [mailto:[email protected]] On Behalf Of Thomas Morin > Sent: Friday, December 15, 2017 5:42 AM > To: Fedyk, Don <[email protected]>; Marco Marzetti > <[email protected]> > Cc: [email protected] > Subject: Re: [bess] draft-ietf-bess-evpn-overlay-10 PMSI with Ingress > Replication > > Hi Don, > > Fedyk, Don, 2017-12-14 20:33: > > I think the gray area is that this draft talks about BUM traffic and > > ingress replication and then has a section on Multicast tunnels which > > excludes ingress replication traffic from the tunnels. > > No, ingress replication is not excluded at all: > > The following tunnel types as defined in [RFC6514] can be used in > the PMSI tunnel attribute for VXLAN/NVGRE: > > + 3 - PIM-SSM Tree > + 4 - PIM-SM Tree > + 5 - BIDIR-PIM Tree > + 6 - Ingress Replication > > > If you are using point to point VXLAN/NVGRE tunnels then ingress > > replication is default [...] > > This formulation surprises me: that some implementations behave as you > describe is possibly true (this seems to be the case of the implementation > that triggered this discussion), but I don't know about any text in the specs > we are discussing that would imply such a 'default'. > > You might have implementations that in the absence of any local > configuration for an EVPN instance on which type of tunnel to use for BUM, > will default to ingress replication: this is fine, out of the scope of what is > specified for interop, and not breaking other implementations (as long, of > course, that what is chosen locally is then advertised as expected in a PMSI > Tunnel Attribute). > > > > but IMET is being used to identify the NVE IP. I read RFC7432 and > > RFC6514 in this area and thought that the PMSI attribute MUST be set > > when there is an Inclusive Multicast Ethernet tag IMET. > > Yes! (the text of RFC7432 quoted by Ali reminds us that) > > > > I can see two possible fixes: > > - Specify that the PMSI attribute MUST be set if there is an > > IMET route and specify correct attribute. > > Given the content of RFC7432 and the fact that this is a normative ref of > draft-ietf-bess-evpn-overlay, I think that we don't need to repeat this MUST > in draft-ietf-bess-evpn-overlay. That is, unless we explicitly identify an > ambiguous piece of text. > > > - Allow that ingress replication is default when PMSI is > > absent but accept PMSI that specifies ingress replication. > > > > I don't think we should do that. It would overnight make non-compliant pre- > standard implementation of draft-ietf-bess-evpn-overlay, without a rationale > to do so except coping with an implementation that assumed a bit too much. > > Best, > > -Thomas > > > > > From: BESS [mailto:[email protected]] On Behalf Of Marco Marzetti > > Sent: Thursday, December 14, 2017 9:21 AM > > To: Thomas Morin <[email protected]> > > Cc: [email protected] > > Subject: Re: [bess] draft-ietf-bess-evpn-overlay-10 PMSI with Ingress > > Replication > > > > Hello, > > > > I have encountered an implementation that is not attaching any PMSI to > > the IMET. > > The authors think they don't really need it because they only support > > Ingress Replication. > > Such behavior breaks interoperability with other implementations that > > are dropping the NLRI if PMSI is not attached. > > > > So i looked at draft-ietf-bess-evpn-overlay-10 and noticed that > > there's no clear indication of what the proper behavior is. > > As said i assumed i had to look at RFC7432 and RFC6514 (and i did it), > > but i wasn't 100% sure and i preferred to ask. > > > > Onestly you already made my day by confirming what i thought. > > My suggestion was to make things more clear, but i admit that it could > > look redundant. > > > > Thanks > > > > > > > > > > > > > > > > On Thu, Dec 14, 2017 at 2:39 PM, Thomas Morin > <[email protected] > > m> wrote: > > > Hi Marco, > > > > > > Marco Marzetti, 2017-12-14 12:25: > > > > I am writing this email asking you to clarify what's the > > > suggested > > > > behavior when PMSI Tunnel Type is set to "Ingress Replication" > > > (type > > > > 6) as draft-ietf-bess-evpn-overlay-10 only suggests what to do > > > with > > > > multicast tunnel trees. > > > > > > > > I think the originating PE should conform with RFC6514 and > > > RFC7432 > > > > (from which you've taken inspiration) and always (RFC2119 MUST) > > > > attach PMSI Tunnel attribute with the Tunnel Type set to Ingress > > > > Replication and Tunnel Identifier set to a routable address of > > > the PE > > > > itself (more specifically NVE's IP address). > > > > > > > > Is that correct? > > > > In that case i suggest to add the following line at the end of > > > > Section 9. > > > > """ > > > > For Ingress Replication the PE should follow what's stated in > > > RFC6514 > > > > Section 5 . > > > > """ > > > > > > The text of section 9 lists "Ingress Replication" in the list of > > > tunnel types that can be used. My understanding is that, in the > > > absence of anything being specifically said for Ingress Replication, > > > an implementation should follow what is said in RFC7432 and RFC6514. > > > (What > > > other specs could it follow to implement this supported type ? > > > RFC7432 > > > and RFC6514 are more than an inspiration here, these are specs that > > > the document refers to explicitly) > > > > > > So I'm not sure that it is useful or needed to add text. > > > > > > Can you perhaps expand on why the current text would possibly be > > > ambiguous, misleading or incomplete...? > > > > > > -Thomas > > > > > > > > > > > -- > > Marco > > _______________________________________________ > BESS mailing list > [email protected] > https://urldefense.proofpoint.com/v2/url?u=https- > 3A__www.ietf.org_mailman_listinfo_bess&d=DwICAg&c=HAkYuh63rsuhr6Sc > bfh0UjBXeMK-ndb3voDTXcWzoCI&r=CRB2tJiQePk0cT-h5LGhEWH- > s_xXXup3HzvBSMRj5VE&m=tHiUTn9_QXrhs3cw- > Dn9_qwR3VK2xWv72DcpoOfR_SI&s=VxylPoVhzXC58hBsqToxzhUK6-3kfy- > ktUi7A9KZDcs&e= _______________________________________________ BESS mailing list [email protected] https://www.ietf.org/mailman/listinfo/bess
