I disagree. The proposed text contains four Binding TLV usage examples which are not qualitatively different from the two usage examples already included in section 2.4.3 of draft-ietf-isis-segment-routing-extensions-02. Additional usage examples are needed to clarify how the TLVs and sub-TLVs defined in this document should be used, without ambiguity.
As an example of the lack of clarity in the current text, draft-ietf-isis-segment-routing-extensions-02 contains two different sub-TLVs for specifying SID/Label values in the Binding TLV. The two options are the SID/Label Sub-TLV (section 2.3) and the Prefix-SID Sub-TLV (section 2.1). The current text does not clearly explain under what circumstances the two different sub-TLVs should be used in the Binding TLV. The proposed text makes the usage clear by means of examples. Chris -----Original Message----- From: Stefano Previdi (sprevidi) [mailto:[email protected]] Sent: Friday, August 01, 2014 1:54 AM To: Uma Chunduri Cc: Chris Bowers; [email protected]; [email protected] Subject: Re: [Isis-wg] comment on draft-ietf-isis-segment-routing-extensions-02 Uma, I agree. I think we also explicitly stated this during our meeting in Toronto (from the minutes): -------------------------------------------------------------------- Uma: Needed to reference use cases in Hannes' draft. Hannes: Perhaps what we could do is add some practical examples for RSVP, BGP, and LDP LSPs binding. Not formal use cases. Stefano: Would rather not go into applications in this ISIS draft. Peter Psenak: Should go into a separate document that could be referenced from both ISIS and OSPF. Alia Atlas: There is a SPRING WG for such a document. ------------------------------------------------------------------- Now, note that: draft-filsfils-spring-segment-routing draft-filsfils-spring-segment-routing-ldp-interop describe the use case of the SR Mapping Server that is implemented using the Binding TLV. As you suggested, Hannes drafts can be combined so to produce a use-case document (in spring) for the Binding TLV RSVP-based use-cases. s. On Jul 31, 2014, at 11:55 PM, Uma Chunduri wrote: > [CC'ed Spring WG] > > I agree with what Chris said below in principle. But all this should not be > obviously part of ISIS/IGP extensions WG documents.. > > Use cases for binding TLVs are explained in great details in 2 key > documents (had to shuffle through to get here) - > > 1. > http://tools.ietf.org/html/draft-gredler-rtgwg-igp-label-advertisement-05 > 2. http://tools.ietf.org/html/draft-gredler-spring-mpls-06 > > IMO, both are very useful documents. > It would be good to combine both of these and publish as a "spring " > document and eventually it should progress there. > AFAICT, Both ISIS and OSPF should refer the same eventually to get more > clarity and use of binding TLVs described currently. > > -- > Uma C. > > From: Isis-wg [mailto:[email protected]] On Behalf Of Chris > Bowers > Sent: Thursday, July 31, 2014 2:42 PM > To: [email protected] > Subject: [Isis-wg] comment on > draft-ietf-isis-segment-routing-extensions-02 > > All, > > The current text of draft-ietf-isis-segment-routing-extensions-02 does not > clearly explain the usage of the Binding TLV for advertising LSPs created > using other protocols. I would like to propose the following text to be > included as section 2.5 . > > Thanks, > Chris > > ---------------- > > 2.5 Binding TLV usage examples > > This section gives examples of using the Binding TLV to advertise SID/label > bindings associated with RSVP-TE, LDP, and BGP labeled-unicast LSPs. It also > includes an example of advertising a context-id for egress node protection. > All of the examples assume that the Binding TLV weight=1 and metric=100. > > 2.5.1 Advertising an RSVP-TE LSP using the Binding TLV > > Assume that R1 has signaled an RSVP-TE LSP to egress router (R4) with > router-id=10.4.4.4, with ER0 = (192.1.2.2 [strict], 192.2.3.2 [strict], > 192.3.4.2 [strict]). R1 can advertise a locally significant label binding for > this LSP (with label value=1099) using the following values and sub-TLVs in > the Binding TLV. > > Binding-TLV: F-bit=0, M-bit=0, weight=1, range=1, prefix length=32, > FEC prefix=10.4.4.4 SID/Label Sub-TLV: label=1099 ERO Metric sub-TLV: > metric=100 > IPv4 ERO sub-TLV: L-bit=0, IPv4 address=192.1.2.2 > IPv4 ERO sub-TLV: L-bit=0, IPv4 address=192.2.3.2 > IPv4 ERO sub-TLV: L-bit=0, IPv4 address=192.3.4.2 > > 2.5.2 Advertising an LDP LSP using the Binding TLV > > Assume that R5 has learned a FEC-label binding via LDP for FEC=10.8.8.8/32. > R5 can advertise a locally significant label binding for this LSP (with label > value=5099) using the following values and sub-TLVs in the Binding TLV. > > Binding TLV: F-bit=0, M-bit=0, weight=1, range=1, prefix length=32, > FEC prefix=10.8.8.8 SID/Label Sub-TLV: label=5099 ERO Metric sub-TLV: > metric=100 > IPv4 ERO sub-TLV: L-bit=1, IPv4 address=10.8.8.8 > > 2.5.3 Advertising a BGP labeled-unicast LSP using the Binding TLV > > Assume that R9 has used BGP labeled-unicast to learn a label binding for > prefix 10.15.15.15/32 with BGP next-hop=10.12.12.12. R9 can advertise a > locally significant label binding for this LSP (with label value=7099) using > the following values and sub-TLVs in the Binding TLV. > > Binding-TLV: F-bit=0, M-bit=0, weight=1, range=1, prefix length=32, > FEC prefix=10.15.15.15 SID/Label Sub-TLV: label=7099 ERO Metric > sub-TLV: metric=100 > IPv4 ERO sub-TLV: L-bit=1, IPv4 address=10.12.12.12 > > 2.5.4 Advertising a context-id for egress node protection using the > Binding TLV > > Assume that R22 is configured in the protector role to provide egress node > protection for R21 using context-id=10.0.0.21. R22 can advertise the label > associated with this context-id (with label value=8099) using the following > values and sub-TLVs in the Binding TLV. > > Binding TLV: F-bit=0, M-bit=1, weight=1, range=1, prefix length=32, > FEC prefix=10.0.0.21 SID/Label Sub-TLV: label=8099 > > ---------------- > > > > _______________________________________________ > Isis-wg mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/isis-wg _______________________________________________ spring mailing list [email protected] https://www.ietf.org/mailman/listinfo/spring
