Hi Greg, Thanks for your suggestion. I think your suggestion is good, we will modify it in the next version.
Regards, Haibo |-----Original Message----- |From: Greg Mirsky [mailto:gregimir...@gmail.com] |Sent: Sunday, March 20, 2022 4:29 AM |To: Wanghaibo (Rainsword) <rainsword.w...@huawei.com> |Cc: draft-wang-bess-sbfd-discrimina...@ietf.org; BESS <b...@ietf.org>; rtg-bfd |WG <rtg-bfd@ietf.org> |Subject: Re: A question about the draft-wang-bess-sbfd-discriminator | |Hi Haibo, |thank you for the clarification. I may suggest a text for Section 3: | |In some EVPN deployments, for example, when it spans over multiple domains, |only one of a pair of interconnected PEs benefits from monitoring the status of |the connection. In such a case, using S-BFD [RFC7880] is advantageous as it |reduces the load on one of the PEs while providing the benefit of faster |convergence. The following sections provide examples of EVPNs that would |benefit from using S-BFD. | |What are your thoughts? | |Regards, |Greg | |On Tue, Mar 15, 2022 at 7:18 PM Wanghaibo (Rainsword) < |rainsword.w...@huawei.com> wrote: | |> Hi Greg, |> |> Thanks for you comments. |> |> Yes, the resources will save at PE1 and PE2 as figure 1. This is a |> typical 3PE scenario. |> |> The service is like this: |> |> +-----+ +-----+ +-----+ |> |> | UCE1|----| APE1|--------|SPE1 |, |> |> +-----+ +-----+` /+-----+ `. |> |> `, .' `.+-----+ |> |> ...... \/ | SCE1| |> |> /\ `+-----+ |> |> ` `. ,' |> |> +-----+ +-----+,' .+-----+ ` |> |> | uCEn|----| APEn|--------|SPE2 |` |> |> +-----+ +-----+ +-----+ |> |> There may be many Access PEs，used to access User CE. And they |> all multi-homed to a couple Servicc PE, SPE1 and SPE2. |> |> (shown as the PE1 and PE2 as figure 1) |> |> Access PE needs to detect Service PE’s reachability. Access PE |> creates SBFD session as an initiator, SPE as the reflector. This will |> save Service PEs’ resources. |> |> |> |> Regards, |> |> Haibo |> |> |> |> *From:* Greg Mirsky [mailto:gregimir...@gmail.com] |> *Sent:* Tuesday, March 15, 2022 11:12 PM |> *To:* Wanghaibo (Rainsword) <rainsword.w...@huawei.com> |> *Cc:* draft-wang-bess-sbfd-discrimina...@ietf.org; BESS |> <b...@ietf.org>; rtg-bfd WG <rtg-bfd@ietf.org> |> *Subject:* Re: A question about the draft-wang-bess-sbfd-discriminator |> |> |> |> Hi Haibo, |> |> thank you for your expedient response. If I understand the scenario |> you're addressing, it is where a single PE with moderate resources is |> connected to a PE that acts as the edge device for the access network. |> To improve the quality of user experience, customer's PE is connected |> to a secondary PE that is used as a backup. You are concerned that |> maintaining two BFD sessions on the customer's PE might overload the |> resource-limited PE. But isn't that the PE that initiates S-BFD |> sessions toward two access network edge PEs in your draft? I think |> that the savings are on the side of these two PEs, not the subscriber's PE. |Would you agree? |> |> |> |> Regards, |> |> Greg |> |> |> |> On Tue, Mar 15, 2022 at 7:20 AM Wanghaibo (Rainsword) < |> rainsword.w...@huawei.com> wrote: |> |> Hi Greg, |> |> Thanks for your comments. |> |> The scenario you pointed out is a 4PE scenario, but in our |> solution, a large number of scenarios are based on 3PE. |> |> In a 3PE scenario, deploying BFD wastes resources. A large number of |> single-homed PEs may be connected to the dual-homed PEs. The |> dual-homed PEs may not have enough resources to create BFD sessions. |> |> |> |> Regards, |> |> Haibo |> |> |> |> *From:* Greg Mirsky [mailto:gregimir...@gmail.com] |> *Sent:* Tuesday, March 15, 2022 12:44 AM |> *To:* Wanghaibo (Rainsword) <rainsword.w...@huawei.com>; |> draft-wang-bess-sbfd-discrimina...@ietf.org; BESS <b...@ietf.org>; |> rtg-bfd WG <rtg-bfd@ietf.org> |> *Subject:* A question about the draft-wang-bess-sbfd-discriminator |> |> |> |> Hi Haibo and the Authors, |> |> thank you for updating the draft. I've read the new version and have a |> question about the use case presented in the document. There are three |> PEs with two of them providing redundant access to a CE. It appears |> that a more general case would be if both CEs use redundant connections to |the EVPN. |> Asume, PE4 is added and connected to CE2. In that case, it seems |> reasonable that each PE is monitoring remote PEs, i.e., PE1 monitors |> PE3 and PE4, PE2 |> - PE3 and PE4, PE3 - PE1 and PE2, and PE4 - PE1 and PE2. So, now there |> are pairs of S-BFD sessions between PEs connected to CE1 and CE2 |respectively
