Hi, All:
We have found some inconsistencies for the implementation of BGP-LS protocol regarding this “Adj-SID SubTLV ”, please see the following screenshot. I think we should do some works for the related drafts to clarify this ambiguous/easy to be ignored definition. Best Regards. Aijun Wang Network R&D and Operation Support Department China Telecom Corporation Limited Beijing Research Institute,Beijing, China. -----邮件原件----- 发件人: stefano previdi [mailto:[email protected]] 发送时间: 2018年4月3日 15:39 收件人: Peter Psenak 抄送: [email protected]; Ketan Talaulikar (ketant); Acee Lindem (acee); Aijun Wang 主题: Re: [Lsr] Inconsistence regarding the definition of "Adj-SID Sub-TLV" between OSPF and ISIS extension for Segment Routing me too. If we want to align the encoding, we should probably better align the protocol name directly... s. > On Apr 3, 2018, at 9:34 AM, Peter Psenak < <mailto:[email protected]> > [email protected]> wrote: > > On 02/04/18 14:19 , Acee Lindem (acee) wrote: >> Speaking as WG member: >> >> I couldn’t agree more with Ketan. No changes are required to these >> documents. > > as a coauthor of the OSPF/OSPFv3 SR drafts, I fully agree. > > thanks, > Peter > >> >> Thanks, >> >> Acee >> >> *From: *Lsr < <mailto:[email protected]> [email protected]> on behalf >> of "Ketan Talaulikar >> (ketant)" < <mailto:[email protected]> [email protected]> >> *Date: *Monday, April 2, 2018 at 7:36 AM >> *To: *Aijun Wang < <mailto:[email protected]> >> [email protected]> >> *Cc: *" <mailto:[email protected]> [email protected]" < <mailto:[email protected]> >> [email protected]> >> *Subject: *Re: [Lsr] Inconsistence regarding the definition of >> "Adj-SID Sub-TLV" between OSPF and ISIS extension for Segment Routing >> >> Hi Aijun, >> >> I understand what you are referring to now, but these are not >> inconsistencies. ISIS, OSPF and BGP-LS are 3 different protocols. >> Their encodings may not all be the same. ISIS uses 1 byte for >> type/length and has LSP space constraints which you would notice in >> the protocol encodings. OSPF doesn’t have the same challenge and you >> would notice how its TLVs tend to be aligned. BGP-LS is somewhat >> similar to OSPF from these size constraints perspective. >> >> I do not see the implementation challenges in encoding from the two >> IGPs into BGP-LS. It does not make sense to change any of the >> protocol encodings that you ask for currently since implementations >> have been shipping with them for many years. >> >> IMHO it is not necessary to put such constraints for what you call >> “consistency” on these 3 protocol encodings in the future. However, >> we do try to be consistent in semantics as much as possible. >> >> Thanks, >> >> Ketan >> >> *From:*Aijun Wang < <mailto:[email protected]> >> [email protected]> >> *Sent:* 02 April 2018 16:52 >> *To:* Ketan Talaulikar (ketant) < <mailto:[email protected]> [email protected]> >> *Cc:* <mailto:[email protected]> [email protected] >> *Subject:* Re: [Lsr] Inconsistence regarding the definition of >> "Adj-SID Sub-TLV" between OSPF and ISIS extension for Segment Routing >> >> Hi, Ketan: >> >> There is one two-bytes “Reserved” field in “Adjacency Segment >> Identifier” TLV for OSPF extension, but this field doesn’t exist in >> the corresponding TLV for ISIS extension. Every other fields are same. >> >> Corresponding definition in BGP-LS is similar with OSPF(not similar >> with ISIS as I mentioned in previous mail). Then when the router >> reports/redistributes the ISIS LSDB information to BGP protocol, the >> router must add two bytes to the “length” field and add/stuff the >> “reserved” field; but for OSPF LSDB, the router need only copy the >> corresponding fields according. >> >> We have found the error arises from this inconsistency from the real >> router and think it is better to align this definition in different >> IGP protocol. >> >> Update to ISIS related extensions draft may be easier. >> >> Aijun Wang >> >> China Telecom >> >> >> 在 2018年4月2日，18:26，Ketan Talaulikar (ketant) >> < <mailto:[email protected]%3cmailto:[email protected]> >> [email protected]<mailto:[email protected]>> 写道： >> >> Hi Aijun, >> >> Can you clarify what you mean by “inconsistencies”? >> >> Also, you are referring the old version of OSPFv3 SR draft before it >> was aligned with the OSPFv2 SR draft. Please check >> >> <https://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment-routing-ex> >> https://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment-routing-ex >> tensions-11#section-6.1 >> >> OSPF and ISIS are different protocols and there are some differences >> between them. I would not call them inconsistencies. BGP-LS spec >> refers to the individual IGP drafts for interpretation of flags. So >> please specifically point out what inconsistency you are referring to. >> >> Thanks, >> >> Ketan >> >> *From:*Lsr < <mailto:[email protected]%3cmailto:[email protected]> >> [email protected]<mailto:[email protected]>> *On >> Behalf Of *Aijun Wang >> *Sent:* 02 April 2018 14:23 >> *To:* <mailto:[email protected]%3cmailto:[email protected]> >> [email protected]<mailto:[email protected]> >> *Subject:* [Lsr] Inconsistence regarding the definition of "Adj-SID >> Sub-TLV" between OSPF and ISIS extension for Segment Routing >> >> Hi, All: >> >> We found there were some inconsistences for the definition of >> “Adjacency Segment Identifier” between OSPF and ISIS extension for >> segment routing, please see the link below for comparison. >> >> >> <https://tools.ietf.org/html/draft-ietf-isis-segment-routing-extension> >> https://tools.ietf.org/html/draft-ietf-isis-segment-routing-extension >> s-15#section-2.2.1 >> >> >> <https://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment-routing-ex> >> https://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment-routing-ex >> tensions-10#section-7.1 >> >> Here we want to know is there any reason for this inconsistence? We >> think this inconsistence can easily cause error for BGP-LS >> implementation for segment routing extension, as that defined in >> >> <https://tools.ietf.org/html/draft-ietf-idr-bgp-ls-segment-routing-ext-04#section-2.2.1> >> >> https://tools.ietf.org/html/draft-ietf-idr-bgp-ls-segment-routing-ext-04#section-2.2.1, >> which is similar with ISIS extension for SR, but different from OSPF >> extension for SR. >> >> Do we need to make them consistent? It seems change the definition >> in OSPF extension may be less influence for the existing related drafts. >> >> Best Regards. >> >> Aijun Wang >> >> Network R&D and Operation Support Department >> >> China Telecom Corporation Limited Beijing Research >> Institute,Beijing, China. >> >> _______________________________________________ >> Lsr mailing list >> <mailto:[email protected]%3cmailto:[email protected]> >> [email protected]<mailto:[email protected]> >> <https://www.ietf.org/mailman/listinfo/lsr> >> https://www.ietf.org/mailman/listinfo/lsr >> >> >> >> _______________________________________________ >> Lsr mailing list >> <mailto:[email protected]> [email protected] >> <https://www.ietf.org/mailman/listinfo/lsr> >> https://www.ietf.org/mailman/listinfo/lsr >> > > _______________________________________________ > Lsr mailing list > <mailto:[email protected]> [email protected] > <https://www.ietf.org/mailman/listinfo/lsr> > https://www.ietf.org/mailman/listinfo/lsr _______________________________________________ Lsr mailing list <mailto:[email protected]> [email protected] <https://www.ietf.org/mailman/listinfo/lsr> https://www.ietf.org/mailman/listinfo/lsr
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