Re: [spring] About draft-ali-spring-srv6-oam-00
+1 on what Robert mentioned; thanks Robert. Thanks Regards … Zafar From: spring on behalf of Robert Raszuk Date: Saturday, June 2, 2018 at 5:20 AM To: Loa Andersson Cc: "spring@ietf.org" , "Zafar Ali (zali)" , "draft-ali-spring-srv6-...@ietf.org" Subject: Re: [spring] About draft-ali-spring-srv6-oam-00 Hi Loa, Is there any known implementations you can show here which builds its IPv6 load balancing hash bases on the variable length IPv6 extension headers content ? Or is your concern simply a speculation ? :) As Zafar already indicated bunch of IETF work went into proposing to use flow label which is part of base IPv6 header (fixed 40 bytes) - to name a few RFC6437, RFC6438, RFC6294 etc ... for that very purpose. So at min if someone indeed wants to expose himself and construct a hash based on the variable length fields a knob should be provided to allow to configure such network element to skip extension headers. Regards, Robert. On Sat, Jun 2, 2018 at 10:21 AM, Loa Andersson mailto:l...@pi.nu>> wrote: Zafar, My concern is that any load balancing tool might hash on the field where you have the O-bit, if it does OAM traffic and normal payload traffic will take different paths through the network. How do you guarantee this this will not happen? /Loa On 2018-05-29 19:11, Zafar Ali (zali) wrote: Hi Loa, Thanks for your question. O-bit "move" from SRH draft to this SRv6 OAM draft is part of a comment received an agreement made during the LC of the SRH draft. Please review the mail chain https://www.ietf..org/mail-archive/web/ipv6/current/msg30131.html<https://www.ietf.org/mail-archive/web/ipv6/current/msg30131.html>. There was never a suggestion or agreement to "remove" O-bit or SRH.Flags field. Load balancing and ECMP in an SRv6 network are explained in https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-13#section-4.4<https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-13#section-4..4>. An implementation is expected to use the minimum of (source, dest) address and flow label in the outer IPv6 header to compute the hash. RFC6437 describes the use of flow labels to compute a hash for IPv6 packets. Thanks Regards … Zafar *From: *Loa Andersson mailto:l...@pi.nu>> *Date: *Tuesday, May 29, 2018 at 9:48 AM *To: *Huzhibo mailto:huzh...@huawei.com>>, "Zafar Ali (zali)" mailto:z...@cisco.com>>, "draft-ali-spring-srv6-...@ietf.org<mailto:draft-ali-spring-srv6-...@ietf.org>" mailto:draft-ali-spring-srv6-...@ietf.org>>, "spring@ietf.org<mailto:spring@ietf.org>" mailto:spring@ietf.org>> *Cc: *Lizhenbin mailto:lizhen...@huawei.com>>, Yangang mailto:yang...@huawei.com>> *Subject: *Re: [spring] About draft-ali-spring-srv6-oam-00 Folks, I thought we had an agreement to remove the O-bit. As ZhiBo Hu points out other drafts drops it. The obvious reason to not use an O-bit is that if it ever is part of what an multipath functions hash on it will csue OAM traffic and "normal" traffic to use different paths. This defeats the idea with OAM traffic. /Loa On 2018-05-16 06:56, Huzhibo wrote: Hi, draft-ali-spring-srv6-oam-00 says The OAM packets are identified by setting the O-bit in SRH,But I Notice the latest I-D.6man-segment-routing-headerhas removed O-bit in the SRH extension header. I want to confirm that draft-ali-spring-srv6-oam-00 will also remove o-bit or keep the o-bit in the later version? Ths ZhiBo Hu ___ spring mailing list spring@ietf.org<mailto:spring@ietf.org><mailto:spring@ietf.org<mailto:spring@ietf.org>> https://www.ietf.org/mailman/listinfo/spring -- Loa Anderssonemail: l...@pi..nu<mailto:l...@pi.nu><mailto:l...@pi.nu<mailto:l...@pi.nu>> Senior MPLS Expert Bronze Dragon Consulting phone: +46 739 81 21 64 ___ spring mailing list spring@ietf.org<mailto:spring@ietf.org> https://www.ietf.org/mailman/listinfo/spring -- Loa Anderssonemail: l...@pi.nu<mailto:l...@pi.nu> Senior MPLS Expert Bronze Dragon Consulting phone: +46 739 81 21 64 ___ spring mailing list spring@ietf.org<mailto:spring@ietf.org> https://www.ietf.org/mailman/listinfo/spring ___ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring
Re: [spring] About draft-ali-spring-srv6-oam-00
Hi Loa, Is there any known implementations you can show here which builds its IPv6 load balancing hash bases on the *variable length* IPv6 extension headers content ? Or is your concern simply a speculation ? :) As Zafar already indicated bunch of IETF work went into proposing to use flow label which is part of base IPv6 header (fixed 40 bytes) - to name a few RFC6437, RFC6438, RFC6294 etc ... for that very purpose. So at min if someone indeed wants to expose himself and construct a hash based on the variable length fields a knob should be provided to allow to configure such network element to skip extension headers. Regards, Robert. On Sat, Jun 2, 2018 at 10:21 AM, Loa Andersson wrote: > Zafar, > > My concern is that any load balancing tool might hash on the field where > you have the O-bit, if it does OAM traffic and normal payload traffic > will take different paths through the network. > > How do you guarantee this this will not happen? > > /Loa > > On 2018-05-29 19:11, Zafar Ali (zali) wrote: > >> Hi Loa, >> >> Thanks for your question. >> >> O-bit "move" from SRH draft to this SRv6 OAM draft is part of a comment >> received an agreement made during the LC of the SRH draft. Please review >> the mail chain https://www.ietf.org/mail-arch >> ive/web/ipv6/current/msg30131.html. There was never a suggestion or >> agreement to "remove" O-bit or SRH.Flags field. >> >> Load balancing and ECMP in an SRv6 network are explained in >> https://tools.ietf.org/html/draft-ietf-6man-segment-routing- >> header-13#section-4.4. An implementation is expected to use the minimum >> of (source, dest) address and flow label in the outer IPv6 header to >> compute the hash. RFC6437 describes the use of flow labels to compute a >> hash for IPv6 packets. >> >> Thanks >> >> Regards … Zafar >> >> *From: *Loa Andersson >> *Date: *Tuesday, May 29, 2018 at 9:48 AM >> *To: *Huzhibo , "Zafar Ali (zali)" , >> "draft-ali-spring-srv6-...@ietf.org" , >> "spring@ietf.org" >> *Cc: *Lizhenbin , Yangang >> *Subject: *Re: [spring] About draft-ali-spring-srv6-oam-00 >> >> Folks, >> >> I thought we had an agreement to remove the O-bit. As ZhiBo Hu points >> >> out other drafts drops it. >> >> The obvious reason to not use an O-bit is that if it ever is part of >> >> what an multipath functions hash on it will csue OAM traffic and >> >> "normal" traffic to use different paths. This defeats the idea with >> >> OAM traffic. >> >> /Loa >> >> On 2018-05-16 06:56, Huzhibo wrote: >> >> Hi, >> >> draft-ali-spring-srv6-oam-00 says The OAM packets are identified by >> >> setting the O-bit in SRH,But I Notice the latest >> >> I-D.6man-segment-routing-headerhas removed O-bit in the SRH extension >> >> header. I want to confirm that draft-ali-spring-srv6-oam-00 will also >> >> remove o-bit or keep the o-bit in the later version? >> >> Ths >> >> ZhiBo Hu >> >> ___ >> >> spring mailing list >> >> spring@ietf.org<mailto:spring@ietf.org> >> >> https://www.ietf.org/mailman/listinfo/spring >> >> -- >> >> Loa Anderssonemail: l...@pi.nu<mailto:l...@pi.nu> >> >> Senior MPLS Expert >> >> Bronze Dragon Consulting phone: +46 739 81 21 64 >> >> >> >> ___ >> spring mailing list >> spring@ietf.org >> https://www.ietf.org/mailman/listinfo/spring >> >> > -- > > > Loa Anderssonemail: l...@pi.nu > Senior MPLS Expert > Bronze Dragon Consulting phone: +46 739 81 21 64 > > ___ > spring mailing list > spring@ietf.org > https://www.ietf.org/mailman/listinfo/spring > ___ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring
Re: [spring] About draft-ali-spring-srv6-oam-00
Zafar, My concern is that any load balancing tool might hash on the field where you have the O-bit, if it does OAM traffic and normal payload traffic will take different paths through the network. How do you guarantee this this will not happen? /Loa On 2018-05-29 19:11, Zafar Ali (zali) wrote: Hi Loa, Thanks for your question. O-bit "move" from SRH draft to this SRv6 OAM draft is part of a comment received an agreement made during the LC of the SRH draft. Please review the mail chain https://www.ietf.org/mail-archive/web/ipv6/current/msg30131.html. There was never a suggestion or agreement to "remove" O-bit or SRH.Flags field. Load balancing and ECMP in an SRv6 network are explained in https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-13#section-4.4. An implementation is expected to use the minimum of (source, dest) address and flow label in the outer IPv6 header to compute the hash. RFC6437 describes the use of flow labels to compute a hash for IPv6 packets. Thanks Regards … Zafar *From: *Loa Andersson *Date: *Tuesday, May 29, 2018 at 9:48 AM *To: *Huzhibo , "Zafar Ali (zali)" , "draft-ali-spring-srv6-...@ietf.org" , "spring@ietf.org" *Cc: *Lizhenbin , Yangang *Subject: *Re: [spring] About draft-ali-spring-srv6-oam-00 Folks, I thought we had an agreement to remove the O-bit. As ZhiBo Hu points out other drafts drops it. The obvious reason to not use an O-bit is that if it ever is part of what an multipath functions hash on it will csue OAM traffic and "normal" traffic to use different paths. This defeats the idea with OAM traffic. /Loa On 2018-05-16 06:56, Huzhibo wrote: Hi, draft-ali-spring-srv6-oam-00 says The OAM packets are identified by setting the O-bit in SRH,But I Notice the latest I-D.6man-segment-routing-headerhas removed O-bit in the SRH extension header. I want to confirm that draft-ali-spring-srv6-oam-00 will also remove o-bit or keep the o-bit in the later version? Ths ZhiBo Hu ___ spring mailing list spring@ietf.org<mailto:spring@ietf.org> https://www.ietf.org/mailman/listinfo/spring -- Loa Anderssonemail: l...@pi.nu<mailto:l...@pi.nu> Senior MPLS Expert Bronze Dragon Consulting phone: +46 739 81 21 64 ___ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring -- Loa Anderssonemail: l...@pi.nu Senior MPLS Expert Bronze Dragon Consulting phone: +46 739 81 21 64 ___ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring
Re: [spring] About draft-ali-spring-srv6-oam-00
Hi Loa, Thanks for your question. O-bit "move" from SRH draft to this SRv6 OAM draft is part of a comment received an agreement made during the LC of the SRH draft. Please review the mail chain https://www.ietf.org/mail-archive/web/ipv6/current/msg30131.html. There was never a suggestion or agreement to "remove" O-bit or SRH.Flags field. Load balancing and ECMP in an SRv6 network are explained in https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-13#section-4.4. An implementation is expected to use the minimum of (source, dest) address and flow label in the outer IPv6 header to compute the hash. RFC6437 describes the use of flow labels to compute a hash for IPv6 packets. Thanks Regards … Zafar From: Loa Andersson Date: Tuesday, May 29, 2018 at 9:48 AM To: Huzhibo , "Zafar Ali (zali)" , "draft-ali-spring-srv6-...@ietf.org" , "spring@ietf.org" Cc: Lizhenbin , Yangang Subject: Re: [spring] About draft-ali-spring-srv6-oam-00 Folks, I thought we had an agreement to remove the O-bit. As ZhiBo Hu points out other drafts drops it. The obvious reason to not use an O-bit is that if it ever is part of what an multipath functions hash on it will csue OAM traffic and "normal" traffic to use different paths. This defeats the idea with OAM traffic. /Loa On 2018-05-16 06:56, Huzhibo wrote: Hi, draft-ali-spring-srv6-oam-00 says The OAM packets are identified by setting the O-bit in SRH,But I Notice the latest I-D.6man-segment-routing-headerhas removed O-bit in the SRH extension header. I want to confirm that draft-ali-spring-srv6-oam-00 will also remove o-bit or keep the o-bit in the later version? Ths ZhiBo Hu ___ spring mailing list spring@ietf.org<mailto:spring@ietf.org> https://www.ietf.org/mailman/listinfo/spring -- Loa Anderssonemail: l...@pi.nu<mailto:l...@pi.nu> Senior MPLS Expert Bronze Dragon Consulting phone: +46 739 81 21 64 ___ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring
Re: [spring] About draft-ali-spring-srv6-oam-00
Hi ZhiBo, Excellent question. Thanks for asking. * O-bit was removed as part of comments during LC of https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-12 draft. The comment was that the bit is defined but its usage is not defined. * The plan to bring O-bit definition from SRH specification and O-bit usage from Network Programming document to draft-ali-spring-srv6-oam-00. * Please also note that to keep implementations unaffected, the O-bit position will be kept at the same place as it was defined in the SRH specification. * Please stay tuned to a v01; it will be soon. Should the WG has any other question, we will be glad to address them in v01. Thanks Regards … Zafar From: HuzhiboDate: Wednesday, May 16, 2018 at 12:56 AM To: "Zafar Ali (zali)" , "draft-ali-spring-srv6-...@ietf.org" , "spring@ietf.org" Cc: Lizhenbin , Yangang Subject: About draft-ali-spring-srv6-oam-00 Hi, draft-ali-spring-srv6-oam-00 says The OAM packets are identified by setting the O-bit in SRH,But I Notice the latest I-D.6man-segment-routing-header has removed O-bit in the SRH extension header. I want to confirm that draft-ali-spring-srv6-oam-00 will also remove o-bit or keep the o-bit in the later version? Ths ZhiBo Hu ___ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring