Re: [Idr] Mail regarding draft-ietf-idr-segment-routing-te-policy
Nandan Saha <nandan@arista.com> Tue, 09 July 2019 05:06 UTC
Return-Path: <nandan@arista.com>
X-Original-To: idr@ietfa.amsl.com
Delivered-To: idr@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 32CC9120100 for <idr@ietfa.amsl.com>; Mon, 8 Jul 2019 22:06:38 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.704
X-Spam-Level:
X-Spam-Status: No, score=-0.704 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, PDS_NO_HELO_DNS=1.295, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=no autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=arista.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id I6NNJVCtylcI for <idr@ietfa.amsl.com>; Mon, 8 Jul 2019 22:06:36 -0700 (PDT)
Received: from mail-ot1-x32f.google.com (mail-ot1-x32f.google.com [IPv6:2607:f8b0:4864:20::32f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 143431200EC for <idr@ietf.org>; Mon, 8 Jul 2019 22:06:35 -0700 (PDT)
Received: by mail-ot1-x32f.google.com with SMTP id o101so18614623ota.8 for <idr@ietf.org>; Mon, 08 Jul 2019 22:06:35 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=e7uAOdyxIJFt5BDh2bneY8ng90W8I2iU2otpU7DV2AY=; b=j1JbGQPIxaV5xOz8TMPwLpwqTlXrBXxgUra+ASkSfhDPRndTj1oCmb7I47NDUc0IS3 KoMqy5Yr8wgoJ7hsfwRV9VApQmUnf9w6H4FJ4g8O3/AqiTVbaXBI2WA0ZUT7VsNqT6uC 40nCO5dX0Gc5eFX9ikAwMMDoiV8YBXHHRY1iat08GmDu6/t61PQjBK4u9Gz7cBeZi81B bGWI7VGiLJZcq6MDl33k6OcH/hzip5dyvJR8bqEvGdZ7mAXmARp6xzC4epXcPMW7YmbJ K4lkQEW816sp+jB4uiTaX4TuqUXj7qQ55tn95IocKL6sV+j/WedrF3YLeLAApE+36RWL Lllg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=e7uAOdyxIJFt5BDh2bneY8ng90W8I2iU2otpU7DV2AY=; b=bN7Taebp/V9nCj+EVSKqTPH879LPZxK8Oz0Lo8I3tfljU7pbFuvwNy2ui8OJkXUUgc wT6L8gYip4ecjUIt9j+pQhuJMmJMl0LctbrgnzW4kbHyzeRNdIvsOzxXPGOV1znskuis 5tkRahcC2R0F0PolmLBbrjGwlHfj3VXFl3hS5LwrNcXMcHwEPqyB/+tProTqc3KMkBdl 1sO/TQR4vkRZOUM6eYoljPDDeCUNbID5M0H/Jx1XcXAG7LoDkGsdBdBeHn5VuAVEVzu6 G1OOpl+KczgVyFa7sISihLzvfsztLeKkPPaIUGMppWsZMOaFwKz88UwyA4YcgTD08PCe fo7g==
X-Gm-Message-State: APjAAAUsVkZjsvRFb9GcICLECmvxr8jLn2MkjyU2FI3Y9ld2+wRv/2Kg 8FlKCXhA6caVTf0MOtkA44yZfdGAdItx7YRyZe/5eh3juxearqcsDTFT6TLQ8LywcJewcM7c7Nu 1DGlDdIcEQVImUQDG2yZTxNiUdDKJX/TLOJ4lJNSIYtgtNkMscDiHBrzHykXJzEN32QhJDuyIRA ZyFMtGCWs=
X-Google-Smtp-Source: APXvYqzJdBujTqjwuKRTiXnbr7auRQVkL9QWDdmxww5QMSvEZImgTi6SKupHjIT14lr0kSEnds5Z1psS/3sHexpJjsk=
X-Received: by 2002:a9d:4c8:: with SMTP id 66mr16927771otm.214.1562648795067; Mon, 08 Jul 2019 22:06:35 -0700 (PDT)
MIME-Version: 1.0
References: <993db9e45983acc9769af61bf786a6d6@mail.gmail.com> <SN6PR11MB284516BC1430BFFA5E494C0EC13B0@SN6PR11MB2845.namprd11.prod.outlook.com> <CAHhGMfGRgdDTam97sb5dYZQHBLLHpTj85yJ7oL5w7wrB3+q3jA@mail.gmail.com> <SN6PR11MB28451163BCFFD7E2A2DFBFA9C1320@SN6PR11MB2845.namprd11.prod.outlook.com> <CAHhGMfF3XvN4UhedzGSMSA_Qg9JHRp55Vw9enAzsmAh0BBmZ-Q@mail.gmail.com> <DM5PR11MB2027233E97E8949D36D48222C1FB0@DM5PR11MB2027.namprd11.prod.outlook.com> <CAHhGMfGF0kC27GZT4KXMJ835NEyT0kJ8FNCm663h5hW8Mga6Dw@mail.gmail.com> <DM5PR11MB2027BFDCB48266BF271063FFC1F60@DM5PR11MB2027.namprd11.prod.outlook.com>
In-Reply-To: <DM5PR11MB2027BFDCB48266BF271063FFC1F60@DM5PR11MB2027.namprd11.prod.outlook.com>
From: Nandan Saha <nandan@arista.com>
Date: Tue, 09 Jul 2019 10:36:23 +0530
Message-ID: <CAE+itjch5GWWxxBa4rUD2qR_f187=fb-1YspC63UUKMT2hcxxA@mail.gmail.com>
To: "Ketan Talaulikar (ketant)" <ketant@cisco.com>
Cc: Gurusiddesh Nidasesi <gurusiddesh.nidasesi@ipinfusion.com>, "idr@ietf.org" <idr@ietf.org>, Chaitanya Varma <chaitanya.varma@ipinfusion.com>, Ramanathan Selvamani <ramanathan.selvamani@ipinfusion.com>
Content-Type: multipart/alternative; boundary="00000000000056d960058d38864c"
X-CLOUD-SEC-AV-Info: arista,google_mail,monitor
X-CLOUD-SEC-AV-Sent: true
X-Gm-Spam: 0
X-Gm-Phishy: 0
Archived-At: <https://mailarchive.ietf.org/arch/msg/idr/xrYoUzyjjrAKvemRRd0s10QaCdo>
Subject: Re: [Idr] Mail regarding draft-ietf-idr-segment-routing-te-policy
X-BeenThere: idr@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Inter-Domain Routing <idr.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/idr>, <mailto:idr-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/idr/>
List-Post: <mailto:idr@ietf.org>
List-Help: <mailto:idr-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/idr>, <mailto:idr-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 09 Jul 2019 05:06:38 -0000
Hi Ketan, Maybe it makes sense to reword this a little bit? The point about multiple RTs in the update is fine, but the confusion probably stems from "match one of the BGP identifiers" If one or more route-targets are present, then at least one route target MUST match one of the BGP Identifiers of the receiver in order to If one or more route-targets are present, then at least one route target MUST match the BGP Identifier of the receiver in order Thanks, Nandan On Mon, Jul 8, 2019 at 10:46 AM Ketan Talaulikar (ketant) <ketant@cisco.com> wrote: > Hi Gurusiddesh, > > > > The reason for allowing multiple RTs is if the same SR Policy needs to be > delivered to multiple headend routers. It need not be read as a BGP router > having more than one BGP identifier. > > > > Thanks, > > Ketan > > > > *From:* Gurusiddesh Nidasesi <gurusiddesh.nidasesi@ipinfusion.com> > *Sent:* 08 July 2019 10:09 > *To:* Ketan Talaulikar (ketant) <ketant@cisco.com> > *Cc:* Chaitanya Varma <chaitanya.varma@ipinfusion.com>; idr@ietf.org; > Ramanathan Selvamani <ramanathan.selvamani@ipinfusion.com> > *Subject:* Re: [Idr] Mail regarding > draft-ietf-idr-segment-routing-te-policy > > > > Hi Ketan, > > > > Thanks for the response. > > Additionally, we have more queries as follows: > > > > > > The draft says that > > "One or more IPv4 address format route-target extended community > > ([RFC4360 <https://tools.ietf.org/html/rfc4360>]) attached to the SR Policy advertisement and that > > indicates the intended head-end of such SR Policy advertisement." > > > > Here one or more RTs are attached to match specific headend? > > > > " If one or more route-targets are present, then at least one route > target MUST match one of the BGP Identifiers of the receiver in order > for the update to be considered usable." > > Can a BGP peer have more than one BGP identifier? > > > > > > On Wed, Jul 3, 2019 at 7:29 PM Ketan Talaulikar (ketant) <ketant@cisco.com> > wrote: > > Hi Gurusiddesh, > > > > The purpose of the RT is to indicate the specific headend for which the SR > Policy is for. So I am not sure of the scenario where multiple RTs will be > associated with a single update. > > > > Even if it were, I am not sure we normally strip out RTs automatically > without some specific route policy being applied. > > > > Thanks, > > Ketan > > > > *From:* Gurusiddesh Nidasesi <gurusiddesh.nidasesi@ipinfusion.com> > *Sent:* 26 June 2019 12:56 > *To:* Ketan Talaulikar (ketant) <ketant@cisco.com> > *Cc:* Chaitanya Varma <chaitanya.varma@ipinfusion.com>; idr@ietf.org; > Ramanathan Selvamani <ramanathan.selvamani@ipinfusion.com> > *Subject:* Re: [Idr] Mail regarding > draft-ietf-idr-segment-routing-te-policy > > > > Hi Ketan, > > > > We have some more doubts as follows: > > > > "Typically, a controller defines the set of policies and advertise > > them to policy head-end routers (typically ingress routers). The > > policy advertisement uses BGP extensions defined in this document. > > The policy advertisement is, in most but not all of the cases, > > tailored for a specific policy head-end. In this case the > > advertisement may sent on a BGP session to that head-end and not > > propagated any further." > > > > If controller sends multiple unique RTs in the same Update message, > > 1. Once the SR policy reaches the Headend, should we strip down that > particular RT to avoid advertising it further? > > > > Thanks > > Gurusiddesh V N > > > > > > > > > > On Wed, May 8, 2019 at 3:58 PM Ketan Talaulikar (ketant) <ketant@cisco.com> > wrote: > > Hi Gurusiddesh, > > > > Please check inline below > > > > *From:* Gurusiddesh Nidasesi <gurusiddesh.nidasesi@ipinfusion.com> > *Sent:* 07 May 2019 17:11 > *To:* Ketan Talaulikar (ketant) <ketant@cisco.com> > *Cc:* Chaitanya Varma <chaitanya.varma@ipinfusion.com>; idr@ietf.org > *Subject:* Re: [Idr] Mail regarding > draft-ietf-idr-segment-routing-te-policy > > > > Hi Ketan, > > > > Thanks for the quick response. > > Additionally, we have more queries as follows > > > > *"Alternatively, a router (i.e., a BGP egress router) advertises SR* > > * Policies representing paths to itself. In this case, it is possible* > > * to send the policy to each head-end over a BGP session to that head-* > > * end, without requiring any further propagation of the policy."* > > > > How does an egress router advertise SR policies representing paths to > itself? > > *[KT] By setting endpoint to it’s own router-id in the NLRI and setting > the ingress router’s router-id in the router-target extended community.* > > Is it done through BGP configuration or any other trigger? > > *[KT] This would be implementation specific based on the > use-case/workflow.* > > > In the above case how ERO (SID-List) is calculated? > > *[KT] This is again implementation specific. It could be done by some TE > module on the egress BGP router that has topology visibility from the > ingress router to itself. It would be kind of reverse of how a headend > computes a path from itself to an endpoint – this is the endpoint computing > path to itself from some headend.* > > *Thanks,* > > *Ketan* > > > > Regards > > Gurusiddesh V N > > > > On Wed, May 1, 2019 at 7:34 PM Ketan Talaulikar (ketant) <ketant@cisco.com> > wrote: > > Hi Chaitanya, > > > > Please check inline below. > > > > *From:* Idr <idr-bounces@ietf.org> *On Behalf Of *Chaitanya Varma > *Sent:* 30 April 2019 13:34 > *To:* idr@ietf.org > *Cc:* Gurusiddesh Nidasesi <gurusiddesh.nidasesi@ipinfusion.com> > *Subject:* [Idr] Mail regarding draft-ietf-idr-segment-routing-te-policy > > > > Hi, > > > > I have couple of queries from the below draft. > > > > https://tools.ietf.org/html/draft-ietf-idr-segment-routing-te-policy-05 > > > > * “ Typically, a controller defines the set of policies and advertise* > > * them to policy head-end routers (typically ingress routers).” * > > > > How do we communicate SR policies from controller? Is it through BGP-SR > session or PCEP session. > > *[KT] This draft is all about using BGP for signalling SR Policies from a > controller to the head-end routers. So yes (b) below.* > > > > a. If it is through PCEP session what happens if the PCC is non-headend? > > b. If it is through BGP-SR what is the role for PCEP between PCE and PCC? > > *[KT] PCEP is another flavour for instantiation of SR Policies. Yet > another option is using netconf/yang or another method for provisioning. > This draft is about using BGP and PCEP is not required.* > > > > * “ Moreover, one or more route-target SHOULD be attached to the* > > > > * advertisement” *How Route-target should be attached to a SR-NLRI > update? > > *[KT] As Route Target Extended Communities attribute – ref sec 1 of the > draft.* > > > > Is it done through local configuration or picked up based on some dynamic > parameter? > > *[KT] It is done by the controller and may be done via local config – > either along with the SR Policy or route policy or even dynamically based > on the head-end address. This would be implementation specific.* > > > > *Thanks,* > > *Ketan* > > > > Appreciate if you can help here. > > > > > > Regards, > > Chaitanya > > > > > .. > > > > > -- > > Thanks, > > Gurusiddesh V N > > > . > > > > > -- > > Thanks, > > Gurusiddesh V N > > > . > > > > > -- > > Thanks, > > Gurusiddesh V N > > > . > _______________________________________________ > Idr mailing list > Idr@ietf.org > https://www.ietf.org/mailman/listinfo/idr >
- [Idr] Mail regarding draft-ietf-idr-segment-routi… Chaitanya Varma
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Susan Hares
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Ketan Talaulikar (ketant)
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Gurusiddesh Nidasesi
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Ketan Talaulikar (ketant)
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Gurusiddesh Nidasesi
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Ketan Talaulikar (ketant)
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Gurusiddesh Nidasesi
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Ketan Talaulikar (ketant)
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Gurusiddesh Nidasesi
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Nandan Saha
- Re: [Idr] Mail regarding draft-ietf-idr-segment-r… Ketan Talaulikar (ketant)