On Thu, Dec 19, 2019 at 11:28 AM Ron Bonica <rbon...@juniper.net> wrote:
> Pablo, > > > > In L3VPN, all of these are combined into a single 20-bit MPLS label. Why > can SRv6 not do likewise? > > > > Ron > > [Gyan] Very good point. All of those are related to BOS=1 vpn service > label. This is covered with BESS in detail in the L3 vpn service SID. > https://tools.ietf.org/pdf/draft-ietf-bess-srv6-services-01.pdf > SRv6 programming is related to the end.x cross connects within the SR > domain similar to in MPLS terms “topmost label”. So the external to SRv6 > domain, PE-CE M-BGP BGP services is really separate covered by the draft > above. > > > Juniper Business Use Only > > *From:* spring <spring-boun...@ietf.org> *On Behalf Of *Pablo Camarillo > (pcamaril) > *Sent:* Thursday, December 19, 2019 6:47 AM > *To:* Wang, Weibin (NSB - CN/Shanghai) <weibin.w...@nokia-sbell.com>; > Gyan Mishra <hayabusa...@gmail.com> > *Cc:* spring@ietf.org; Voyer, Daniel <daniel.vo...@bell.ca> > *Subject:* [spring] End.DT/End.DX SIDs (was Re: USD/USP question in > draft-ietf-spring-srv6-network-programming-06.txt) > > > > Gyan, > > > > The End.DX4/End.DX6 can be seen as an equivalent to the MPLS per-CE VPN > label. > > The End.DT4/End.DT6 can be seen as an equivalent to the MPLS per-VRF VPN > label. > > > > I believe that they cannot be combined. > > > > Cheers, > > Pablo. > > > > *From: *Gyan Mishra <hayabusa...@gmail.com> > *Date: *Sunday, 15 December 2019 at 08:29 > *To: *"Wang, Weibin (NSB - CN/Shanghai)" <weibin.w...@nokia-sbell.com> > *Cc: *"Pablo Camarillo (pcamaril)" <pcama...@cisco.com>, "Voyer, Daniel" < > daniel.vo...@bell.ca>, "spring@ietf.org" <spring@ietf.org> > *Subject: *Re: [spring] USD/USP question in > draft-ietf-spring-srv6-network-programming-06.txt > > > > > > Hi Wang & Pablo & Spring Authors, > > > > Had another question? > > > > These 4 sections. Trying to understand the difference between end.dx4 > end.dx6 and end.dt4 and end.dt6. They both seem very similar. One says > xconnect but other has v4 v6 lookup but for both you have to signal L3 vpn > services sid. Not sure why both SIDs dx dt Sid function why they cannot be > combined. > > > > I noticed this difference below that the dx4 dt4 account for the global > table scenario where the PE-CE is native IPv4 or IPv6. In the MPLS world > that use case is very different in that there is not any L3 vpn label and > do the label stack only had a single topmost label. Also in the MPLS > scenario with IPv6 global table PE-CE with a IPv4 core you require BGP -LU > labeled unicast “send label” to label all the IPv6 prefixed tunneled over > IPv4. Since that scenario is very different with global table does it > make sense to have a separate End.x variant for global table for both IPv4 > and IPv6. > > > > Note that an End.DT6 may be defined for the main IPv6 table in which > > case and End.DT6 supports the equivalent of an IPv6inIPv6 > > decapsulation (without VPN/tenant implication). > > > > 4.4 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*section-4.4__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JAaJnI7_$>. > End.DX6: Decapsulation and IPv6 cross-connect . . . . . . 12 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*page-12__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JH8Abwf7$> > > 4.5 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*section-4.5__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JEh8sRB2$>. > End.DX4: Decapsulation and IPv4 cross-connect . . . . . . 13 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*page-13__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JHAg09NC$> > > 4.6 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*section-4.6__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JHVgWtPg$>. > End.DT6: Decapsulation and specific IPv6 table lookup . . 14 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*page-14__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JA89XfKV$> > > 4.7 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*section-4.7__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JF59SaCO$>. > End.DT4: Decapsulation and specific IPv4 table lookup . . 15 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*page-15__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JICjeckL$> > > > > Also I was trying to understand end.dt46. > > > > So if the PE-CE edge is dual stacked anhas both v4 and v6 you have a VRF > tenant v4 and v6 separate peers signaled via L3 vpn services TLV. So why do > you need this end.dt46 sid > > > > 4.8 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*section-4.8__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JMbbI6-v$>. > End.DT46: Decapsulation and specific IP table lookup . . 16 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*page-16__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JMihsn8k$> > > > > > > Kind Regards, > > > > Gyan > > > > On Sun, Dec 15, 2019 at 2:06 AM Gyan Mishra <hayabusa...@gmail.com> wrote: > > Hi Wang > > > > I have a question regarding the PSP, USP and USD sections I pasted below. > > > > I just sent an email to Spring WG related to PSP and technically why that > is necessary as that is a legacy concept that has parity to MPLS but is not > used today due to QOS issues. Please see that email related to that topic. > > > > > > In the PSP section can If we have to keep PSP can we add verbiage that > states that PSP removal of the SRH header occurs on the Penultimate egress > P node. > > > > In the USP section can we also add that all remaining SRH present in the > packet are popped on the egress PE ultimate node. > > > > In looking at these 3 SID functions the PSP and USP pop the EH and the USP > removes the 6in6 encapsulation so that the other end.x dt4 dt6 etc can pop > the services L3vpn headers. > > > > Why can’t the USD 6in6 encapsulation removal be done on with the USP SID? > > > > Why does the USP and USD SID have to be separate? > > > 4.16.1 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*section-4.16.1__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JNXuPqZh$>. > PSP: Penultimate Segment Pop of the SRH > > > > > > The SRH processing of the End, End.X and End.T behaviors are > > modified: after the instruction "S14. Update IPv6 DA with Segment > > List[Segments Left]" is executed, the following instructions must be > > executed as well: > > > > S14.1. If (updated SL == 0) { > > S14.2. Pop the SRH > > S14.3. } > > > > 4.16.2 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*section-4.16.2__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JLGcpaqu$>. > USP: Ultimate Segment Pop of the SRH > > > > > > The SRH processing of the End, End.X and End.T behaviors are > > modified: the instructions S02-S04 are substituted by the following > > ones: > > > > S02. If (Segments Left == 0) { > > S03. Pop the SRH > > S04. } > > > > 4.16.3 > <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05*section-4.16.3__;Iw!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JKFZ-dKZ$>. > USD: Ultimate Segment Decapsulation > > > > > > The SRH processing of the End, End.X and End.T behaviors are > > modified: the instructions S02-S04 are substituted by the following > > ones: > > > > S02. If (Segments Left == 0) { > > S03. Skip the SRH processing and proceed to the next header > > S04. } > > > > > > Further on, the Upper-layer header processing of the End, End.X and > > End.T behaviors are modified as follows: > > > > > > Kind regards, > > > > Gyan > > > > On Sat, Dec 14, 2019 at 9:08 PM Wang, Weibin (NSB - CN/Shanghai) < > weibin.w...@nokia-sbell.com> wrote: > > Hi Pablo: > > > > After the 2 context assumption in previous version of this draft, “we > assume that there is no other extension header than the SRH.” and “We > assume > > that the SRH may be present multiple times inside each packet”, are > removed in this last draft, I feel a bit confusion on USD SID, as well as > combination of USD & USP. > > > > First, within the content of this last draft, the word “Further on” marked > red in the following pseudocode in section “4.16.3” is hard to understand > if the packet being processed has other EH embed between SRH and > Upper-layer header, such as AH or other EH, then the processing control of > this packet will be passed to normal IPv6 module from current SRH > processing module in SR-Node, so my question is : Can its control after > completing AH processing (for example) be back to SRH module (or call it > pseudocode module) to proceed the next header like “upper-lay header type > ==41 or 4”. > > Or, if not, Did you created a new EH processing protocol stack instance in > parallel to normal IPv6 module within the scope of SRH processing in > SR-node. > > > > 4.16.3. USD: Ultimate Segment Decapsulation > > > > S02. If (Segments Left == 0) { > > S03. Skip the SRH processing and proceed to the next header > > S04. } > > > > Further on, the Upper-layer header processing of the End, End.X and > > End.T behaviors are modified as follows: > > > > End: > > S01. If (Upper-layer Header type == 41 || 4) { > > S02. Remove the outer IPv6 Header with all its extension headers > > S03. Submit the packet to the egress IP FIB lookup and > > transmission to the new destination > > S04. } Else { > > S05. Send an ICMP Parameter Problem message to the Source Address > > Code 4 (SR Upper-layer Header Error), > > Pointer set to the offset of the upper-layer header. > > Interrupt packet processing and discard the packet. > > > > S06. } > > > > From my understanding, the all processing action about specific SID must > be completed successively. That is to say, upon USD, the upper-layer header > (type 41 or 4) must be followed the SRH header being processed currently, > or second SRH following the same rule (of course, the draft not considering > 2 or more successive SRHs). > > > > Second, the mixed SIDs function with combination of USD and USP (even > PSP&USD&USP), I think, it is easy to understand when the two assumption > above exist, but now I think it isn’t clear if you only provide the > following sentence in this draft, i.e. “if … else…” statement: > > “An implementation that supports the USD flavor in conjunction with > > the USP flavor MAY optimize the packet processing by first looking > > whether the conditions for the USD flavor are met, in which case it > > can proceed with USD processing else do USP processing.” > > This confusion is also described in my another mail. Of course, if the > first question is addressed then this confusion does not exist. > > > > By the way, is it really no different in text description before and after > the two context assumption above removed? > > > > > > *Cheers !* > > > > *WANG Weibin* > > _______________________________________________ > spring mailing list > spring@ietf.org > https://www.ietf.org/mailman/listinfo/spring > <https://urldefense.com/v3/__https:/www.ietf.org/mailman/listinfo/spring__;!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JI97MuU_$> > > -- > > Gyan S. Mishra > > IT Network Engineering & Technology > > Verizon Communications Inc. (VZ) > > 13101 Columbia Pike > <https://www.google.com/maps/search/13101+Columbia+Pike?entry=gmail&source=g> > FDC1 3rd Floor > > Silver Spring, MD 20904 > > United States > > Phone: 301 502-1347 > > Email: gyan.s.mis...@verizon.com > > www.linkedin.com/in/networking-technologies-consultant > <https://urldefense.com/v3/__http:/www.linkedin.com/in/networking-technologies-consultant__;!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JI36IPfx$> > > > > -- > > Gyan S. Mishra > > IT Network Engineering & Technology > > Verizon Communications Inc. (VZ) > > 13101 Columbia Pike > <https://www.google.com/maps/search/13101+Columbia+Pike?entry=gmail&source=g> > FDC1 3rd Floor > > Silver Spring, MD 20904 > > United States > > Phone: 301 502-1347 > > Email: gyan.s.mis...@verizon.com > > www.linkedin.com/in/networking-technologies-consultant > <https://urldefense.com/v3/__http:/www.linkedin.com/in/networking-technologies-consultant__;!!NEt6yMaO-gk!QzHlcRglDrowIq4p7kbUU8tNwsbwrneoRiLDYAClyLIXp1ZLWOSxDhU6JI36IPfx$> > > > -- Gyan S. Mishra IT Network Engineering & Technology Verizon Communications Inc. (VZ) 13101 Columbia Pike FDC1 3rd Floor Silver Spring, MD 20904 United States Phone: 301 502-1347 Email: gyan.s.mis...@verizon.com www.linkedin.com/in/networking-technologies-consultant
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