Re: [bess] Closing on Stephane's open issue with draft-ietf-bess-datacenter-gateway
Hi Linda, Sorry that I missed this question from you… Adrian: On page 6, the second Bullet says that “Each GW constructs an import filtering rule to import any route that carries a route target with the same SR domain identifier that the GW itself uses” How about routes associated to a VPN and to a SR domain? The VPN and the SR might use different RTs. Can you have two different Route Target in one advertisement? AF > We certainly don’t want to restrict wider applicability, but our focus is only on connecting together SR domains. We weren’t looking to solve the multi-homed VPN “problem”. AF > The RT is an extended community. Extended communities are carried in the Extended Communities Attribute. The Extended Communities Attribute can carry more than one extended community. Best, Adrian ___ BESS mailing list BESS@ietf.org https://www.ietf.org/mailman/listinfo/bess
Re: [bess] Closing on Stephane's open issue with draft-ietf-bess-datacenter-gateway
Stephan and Robert, The draft proposed scheme is orthogonal to the RTC, correct ? If a GW’s RTC didn’t show that it is interested in a specific RT, the advertisements from other nodes won’t sent to that GW. Adrian: On page 6, the second Bullet says that “Each GW constructs an import filtering rule to import any route that carries a route target with the same SR domain identifier that the GW itself uses” How about routes associated to a VPN and to a SR domain? The VPN and the SR might use different RTs. Can you have two different Route Target in one advertisement? Thank you Linda Dunbar From: BESS On Behalf Of Robert Raszuk Sent: Monday, June 8, 2020 4:53 AM To: slitkows.i...@gmail.com Cc: draft-ietf-bess-datacenter-gate...@ietf.org; Adrian Farrel ; bess-cha...@ietf.org; BESS Subject: Re: [bess] Closing on Stephane's open issue with draft-ietf-bess-datacenter-gateway Stephane, Two points ... 1. It is not clear to me that draft-ietf-bess-datacenter-gateway recommends to use RTC for anything - do they ? If not there is no issue. 2. Also note that RTC can be enabled on a per AF basis hence even if you use it say for SAFI 128 you do not need to use it for SAFI 1. As a general comment I do not see any issues using RTs on non VPN SAFIs. Thx,, R. On Mon, Jun 8, 2020 at 10:26 AM mailto:slitkows.i...@gmail..com>> wrote: Hi Adrian, My point is really tied to what will happen when RTC is enabled (considering draft-ietf-idr-rtc-no-rt). The behavior will be to drop the routes that don't have an RT which will break existing Internet families behavior. " When RTC is applied, on a particular BGP session, to routes of other address families, the default behavior MUST be that routes without any RTs are not distributed on that session. This default "default behavior" applies to all AFI/SAFIs for which a different default behavior has not been defined." Let me run this to IDR to get their feedback (as draft-ietf-idr-rtc-no-rt is owned by IDR). Stephane -Original Message- From: Adrian Farrel mailto:adr...@olddog.co.uk>> Sent: jeudi 4 juin 2020 19:31 To: slitkows.i...@gmail.com<mailto:slitkows.i...@gmail.com> Cc: bess-cha...@ietf.org<mailto:bess-cha...@ietf.org>; bess@ietf.org<mailto:bess@ietf.org>; draft-ietf-bess-datacenter-gate...@ietf.org<mailto:draft-ietf-bess-datacenter-gate...@ietf.org> Subject: Closing on Stephane's open issue with draft-ietf-bess-datacenter-gateway Hi, John and I had a chat today about what we perceive is Stephane's open issue. What we think the concern is is that we are using RTs in conjunction with normal (i.e., non-VPN) routes. We do this to allow gateways to filter their imports based on the RT that applies to the SR domain that it serves. An option was to use the Route Origin extended community instead. RFC 4360, which introduces both the Route Target and the Route Origin extended communities and gives some guidance. Loosely expressed, the RT says which routers should import, the RO says which routers have advertised. In both cases, the text suggests that "One possible use of the community is specified in RFC4364" which implies that there are other acceptable uses. 4364 implies that the RO is used "to uniquely identify the set of routes learned from a particular site." That is (my words), to apply a filter on top of the RT to prevent re-import by a site of routes that match the RT and that were advertised by other entry points to the site. Indeed, the RO would seem to be used (in the 4364 case) only when the RT is also in use. We appreciate that the distinction is pretty delicate, but we think we are right to use RT in this case because we are filtering to import, not to avoid importing. Furthermore, if we used the RO then, to be consistent with 4364, we would still be using the RT anyway. That, we think, disposes of the "RT or RO?" question. Now, we can go back to the original formulation of the question: is it OK to use RT with "non-VPN IP addresses"? Well, we consulted around a bit privately amongst some BGP experts, and we couldn't find anyone to say it was actually a problem. And (of course) no one raised the issue in WG last call - but Matthew might claim that is because the document was only lightly reviewed, and Stephane might claim that this is because he had already raised the point. Obviously, some of the authors know a bit about BGP, and Eric was a lead author on 4364 and drove a lot of the details of what we wrote. Two points in closing: - If someone can show that we break something, we will have to fix it. - If the chairs want to run this point past IDR and BESS explicitly, that would be fine. Hope this helps. Best, Adrian ___ BESS mailing list BESS@ietf.org<mailto:BESS@ietf.org> https://www.ietf.org/mailman/listinfo/bess<https://nam11.safelinks.protection.outlo
Re: [bess] Closing on Stephane's open issue with draft-ietf-bess-datacenter-gateway
Stephane, Two points .. 1. It is not clear to me that draft-ietf-bess-datacenter-gateway recommends to use RTC for anything - do they ? If not there is no issue. 2. Also note that RTC can be enabled on a per AF basis hence even if you use it say for SAFI 128 you do not need to use it for SAFI 1. As a general comment I do not see any issues using RTs on non VPN SAFIs. Thx,, R. On Mon, Jun 8, 2020 at 10:26 AM wrote: > Hi Adrian, > > My point is really tied to what will happen when RTC is enabled > (considering > draft-ietf-idr-rtc-no-rt). The behavior will be to drop the routes that > don't have an RT which will break existing Internet families behavior. > " When RTC is applied, on a particular BGP session, to routes of other >address families, the default behavior MUST be that routes without >any RTs are not distributed on that session. This default "default >behavior" applies to all AFI/SAFIs for which a different default >behavior has not been defined." > > Let me run this to IDR to get their feedback (as draft-ietf-idr-rtc-no-rt > is > owned by IDR). > > Stephane > > -Original Message- > From: Adrian Farrel > Sent: jeudi 4 juin 2020 19:31 > To: slitkows.i...@gmail.com > Cc: bess-cha...@ietf.org; bess@ietf.org; > draft-ietf-bess-datacenter-gate...@ietf.org > Subject: Closing on Stephane's open issue with > draft-ietf-bess-datacenter-gateway > > Hi, > > John and I had a chat today about what we perceive is Stephane's open > issue. > > What we think the concern is is that we are using RTs in conjunction with > normal (i.e., non-VPN) routes. We do this to allow gateways to filter their > imports based on the RT that applies to the SR domain that it serves. > > An option was to use the Route Origin extended community instead. > > RFC 4360, which introduces both the Route Target and the Route Origin > extended communities and gives some guidance. Loosely expressed, the RT > says > which routers should import, the RO says which routers have advertised. In > both cases, the text suggests that "One possible use of the community is > specified in RFC4364" which implies that there are other acceptable uses. > > 4364 implies that the RO is used "to uniquely identify the set of routes > learned from a particular site." That is (my words), to apply a filter on > top of the RT to prevent re-import by a site of routes that match the RT > and > that were advertised by other entry points to the site. Indeed, the RO > would > seem to be used (in the 4364 case) only when the RT is also in use. > > We appreciate that the distinction is pretty delicate, but we think we are > right to use RT in this case because we are filtering to import, not to > avoid importing. Furthermore, if we used the RO then, to be consistent with > 4364, we would still be using the RT anyway. > > That, we think, disposes of the "RT or RO?" question. > > Now, we can go back to the original formulation of the question: is it OK > to > use RT with "non-VPN IP addresses"? Well, we consulted around a bit > privately amongst some BGP experts, and we couldn't find anyone to say it > was actually a problem. And (of course) no one raised the issue in WG last > call - but Matthew might claim that is because the document was only > lightly > reviewed, and Stephane might claim that this is because he had already > raised the point. Obviously, some of the authors know a bit about BGP, and > Eric was a lead author on 4364 and drove a lot of the details of what we > wrote. > > Two points in closing: > - If someone can show that we break something, we will have to fix it. > - If the chairs want to run this point past IDR and BESS explicitly, that > would be fine. > > Hope this helps. > > Best, > Adrian > > > ___ > BESS mailing list > BESS@ietf.org > https://www.ietf.org/mailman/listinfo/bess > ___ BESS mailing list BESS@ietf.org https://www.ietf.org/mailman/listinfo/bess
Re: [bess] Closing on Stephane's open issue with draft-ietf-bess-datacenter-gateway
Hi Adrian, My point is really tied to what will happen when RTC is enabled (considering draft-ietf-idr-rtc-no-rt). The behavior will be to drop the routes that don't have an RT which will break existing Internet families behavior. " When RTC is applied, on a particular BGP session, to routes of other address families, the default behavior MUST be that routes without any RTs are not distributed on that session. This default "default behavior" applies to all AFI/SAFIs for which a different default behavior has not been defined." Let me run this to IDR to get their feedback (as draft-ietf-idr-rtc-no-rt is owned by IDR). Stephane -Original Message- From: Adrian Farrel Sent: jeudi 4 juin 2020 19:31 To: slitkows.i...@gmail.com Cc: bess-cha...@ietf.org; bess@ietf.org; draft-ietf-bess-datacenter-gate...@ietf.org Subject: Closing on Stephane's open issue with draft-ietf-bess-datacenter-gateway Hi, John and I had a chat today about what we perceive is Stephane's open issue. What we think the concern is is that we are using RTs in conjunction with normal (i.e., non-VPN) routes. We do this to allow gateways to filter their imports based on the RT that applies to the SR domain that it serves. An option was to use the Route Origin extended community instead. RFC 4360, which introduces both the Route Target and the Route Origin extended communities and gives some guidance. Loosely expressed, the RT says which routers should import, the RO says which routers have advertised. In both cases, the text suggests that "One possible use of the community is specified in RFC4364" which implies that there are other acceptable uses. 4364 implies that the RO is used "to uniquely identify the set of routes learned from a particular site." That is (my words), to apply a filter on top of the RT to prevent re-import by a site of routes that match the RT and that were advertised by other entry points to the site. Indeed, the RO would seem to be used (in the 4364 case) only when the RT is also in use. We appreciate that the distinction is pretty delicate, but we think we are right to use RT in this case because we are filtering to import, not to avoid importing. Furthermore, if we used the RO then, to be consistent with 4364, we would still be using the RT anyway. That, we think, disposes of the "RT or RO?" question. Now, we can go back to the original formulation of the question: is it OK to use RT with "non-VPN IP addresses"? Well, we consulted around a bit privately amongst some BGP experts, and we couldn't find anyone to say it was actually a problem. And (of course) no one raised the issue in WG last call - but Matthew might claim that is because the document was only lightly reviewed, and Stephane might claim that this is because he had already raised the point. Obviously, some of the authors know a bit about BGP, and Eric was a lead author on 4364 and drove a lot of the details of what we wrote. Two points in closing: - If someone can show that we break something, we will have to fix it. - If the chairs want to run this point past IDR and BESS explicitly, that would be fine. Hope this helps. Best, Adrian ___ BESS mailing list BESS@ietf.org https://www.ietf.org/mailman/listinfo/bess
[bess] Closing on Stephane's open issue with draft-ietf-bess-datacenter-gateway
Hi, John and I had a chat today about what we perceive is Stephane's open issue. What we think the concern is is that we are using RTs in conjunction with normal (i.e., non-VPN) routes. We do this to allow gateways to filter their imports based on the RT that applies to the SR domain that it serves. An option was to use the Route Origin extended community instead. RFC 4360, which introduces both the Route Target and the Route Origin extended communities and gives some guidance. Loosely expressed, the RT says which routers should import, the RO says which routers have advertised. In both cases, the text suggests that "One possible use of the community is specified in RFC4364" which implies that there are other acceptable uses. 4364 implies that the RO is used "to uniquely identify the set of routes learned from a particular site." That is (my words), to apply a filter on top of the RT to prevent re-import by a site of routes that match the RT and that were advertised by other entry points to the site. Indeed, the RO would seem to be used (in the 4364 case) only when the RT is also in use. We appreciate that the distinction is pretty delicate, but we think we are right to use RT in this case because we are filtering to import, not to avoid importing. Furthermore, if we used the RO then, to be consistent with 4364, we would still be using the RT anyway. That, we think, disposes of the "RT or RO?" question. Now, we can go back to the original formulation of the question: is it OK to use RT with "non-VPN IP addresses"? Well, we consulted around a bit privately amongst some BGP experts, and we couldn't find anyone to say it was actually a problem. And (of course) no one raised the issue in WG last call - but Matthew might claim that is because the document was only lightly reviewed, and Stephane might claim that this is because he had already raised the point. Obviously, some of the authors know a bit about BGP, and Eric was a lead author on 4364 and drove a lot of the details of what we wrote. Two points in closing: - If someone can show that we break something, we will have to fix it. - If the chairs want to run this point past IDR and BESS explicitly, that would be fine. Hope this helps. Best, Adrian ___ BESS mailing list BESS@ietf.org https://www.ietf.org/mailman/listinfo/bess
