Re: [Bier] Questions about draft-ietf-bier-te-ospfv3

Huaimo Chen <huaimo.chen@futurewei.com> Mon, 08 August 2022 16:49 UTC

Return-Path: <huaimo.chen@futurewei.com>
X-Original-To: bier@ietfa.amsl.com
Delivered-To: bier@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5167BC15A738; Mon, 8 Aug 2022 09:49:17 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.107
X-Spam-Level:
X-Spam-Status: No, score=-2.107 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, RCVD_IN_ZEN_BLOCKED_OPENDNS=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01, URIBL_BLOCKED=0.001, URIBL_DBL_BLOCKED_OPENDNS=0.001, URIBL_ZEN_BLOCKED_OPENDNS=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=futurewei.com
Received: from mail.ietf.org ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id M-7dyKxLK1Us; Mon, 8 Aug 2022 09:49:12 -0700 (PDT)
Received: from NAM11-BN8-obe.outbound.protection.outlook.com (mail-bn8nam11on2100.outbound.protection.outlook.com [40.107.236.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 9405CC14F747; Mon, 8 Aug 2022 09:49:12 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=YCONSjMw/zc519wogVMsy6yzGy+SKlII1Q8yYmLqS2C8ymdp2+xn6tmJ80b7buxt9i0rShm58wft0rTZUsooYl+geRFvfI2fUBfVttyRN3Rb/BP3SJPEYjx7voTLEhEnpwjtprFu6ap0maM67PRv5fbh1p3vDnXpIqWS+F055E45RRDrvc/t1wN0FAajM7JWiIB4gANIEoAO6dw2seINaNMl2PLJLaaZRCPKJOhq7LNT+JxQRnswCEgg8x33yHDx5TjR3/JI1r+u3mTJ9fsZcUH3RdYZstwG4J/YaUQilfyf2mQ4/JN9aBAwRPmcfT5ozsI7lMlPTjmWdiO8on68lQ==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=2hmrGQgUGNvs4d2SSrx8byWWzgViXjdB7U8gc0pJoKs=; b=MqgX4SwtyZuG3/XTCQ1Fd+ngQcldfX8k82UKddqunCnUUZ2AGzddwi/jySf1qNBMqc+aZQFSoRw7GFhqKAV1s9UZbrWpcHqhf9vaLL2rGkfakXXl39rq3rJ2T4r7JFA+sj5XBU+8wKhoZfb/gqfCvP7kuwqnxEC9QMsrdSO58WIRIhyk5hjx2NATRKnenIY6ZsdU0DfHcq9ph/8CMyHpkX4iw8owiXADePn/DiAh6lsUY+mtg1TfYcsh5Qtsdpi0WapOvOR/CoLsAKYzL5TlBcGQ+j4pl2895Nv3bDrdQ1Yy/U/XIxmU7PZ3qlosnSdXlIaZzt+/IYSmutZNozp4vA==
ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=futurewei.com; dmarc=pass action=none header.from=futurewei.com; dkim=pass header.d=futurewei.com; arc=none
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Futurewei.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=2hmrGQgUGNvs4d2SSrx8byWWzgViXjdB7U8gc0pJoKs=; b=RfDVUT1sTC4vqrAOcy7Fr7aCP5mExZz7nVHnBKnmiVGnUk8FpUCGtl7dh3T34RwSnPlzaUTV1G/pNqrbkyeiolS6DtbwMqyQwqxdem6ECTUubRtf7jrvhpnNBo7tvEB6unA806XC5nVsYazla1e3zvxLZgSmzmJT+aoHBZDvkDs=
Received: from BY3PR13MB5044.namprd13.prod.outlook.com (2603:10b6:a03:362::22) by MW5PR13MB5416.namprd13.prod.outlook.com (2603:10b6:303:191::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5482.1; Mon, 8 Aug 2022 16:49:07 +0000
Received: from BY3PR13MB5044.namprd13.prod.outlook.com ([fe80::80ff:2f76:e978:f178]) by BY3PR13MB5044.namprd13.prod.outlook.com ([fe80::80ff:2f76:e978:f178%7]) with mapi id 15.20.5525.009; Mon, 8 Aug 2022 16:49:07 +0000
From: Huaimo Chen <huaimo.chen@futurewei.com>
To: "Jeffrey (Zhaohui) Zhang" <zzhang@juniper.net>, "'bier@ietf.org'" <bier@ietf.org>, "draft-ietf-bier-te-ospfv3@ietf.org" <draft-ietf-bier-te-ospfv3@ietf.org>, 'Toerless Eckert' <tte@cs.fau.de>
Thread-Topic: Questions about draft-ietf-bier-te-ospfv3
Thread-Index: AdiQc154uSeqRyTWQhKwDos3Wp8xOAAaD2ZsBcr0VBAAzxuvEQ==
Date: Mon, 8 Aug 2022 16:49:07 +0000
Message-ID: <BY3PR13MB5044BA9C0C5F2E049997F750F2639@BY3PR13MB5044.namprd13.prod.outlook.com>
References: <BL0PR05MB56522900742591FAA8834A2BD4819@BL0PR05MB5652.namprd05.prod.outlook.com> <BY3PR13MB5044B0C229593D51900CDAE2F2809@BY3PR13MB5044.namprd13.prod.outlook.com> <BL0PR05MB5652D3E4AB34EA33D7337D40D4609@BL0PR05MB5652.namprd05.prod.outlook.com>
In-Reply-To: <BL0PR05MB5652D3E4AB34EA33D7337D40D4609@BL0PR05MB5652.namprd05.prod.outlook.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
msip_labels: MSIP_Label_0633b888-ae0d-4341-a75f-06e04137d755_Enabled=true; MSIP_Label_0633b888-ae0d-4341-a75f-06e04137d755_SetDate=2022-08-07T13:53:15Z; MSIP_Label_0633b888-ae0d-4341-a75f-06e04137d755_Method=Standard; MSIP_Label_0633b888-ae0d-4341-a75f-06e04137d755_Name=0633b888-ae0d-4341-a75f-06e04137d755; MSIP_Label_0633b888-ae0d-4341-a75f-06e04137d755_SiteId=bea78b3c-4cdb-4130-854a-1d193232e5f4; MSIP_Label_0633b888-ae0d-4341-a75f-06e04137d755_ActionId=56dd55f9-ce92-4d92-bb86-e71c75cc574d; MSIP_Label_0633b888-ae0d-4341-a75f-06e04137d755_ContentBits=2;
authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=futurewei.com;
x-ms-publictraffictype: Email
x-ms-office365-filtering-correlation-id: e3226bce-aa69-49d7-935a-08da795de8fa
x-ms-traffictypediagnostic: MW5PR13MB5416:EE_
x-ms-exchange-senderadcheck: 1
x-ms-exchange-antispam-relay: 0
x-microsoft-antispam: BCL:0;
x-microsoft-antispam-message-info: eRlzaO1zp297g7Ggkmjwhvh/LR6R0nSVWRicBWd68+UQCx3rx87gkGkEjI+ivkPv2BO6wbCwa6fm+7fuG+MRIFmUn79OWHHBkr/Vel9ZC7ZbuvAhfZBZhVpv4fBP0HQgcNr4qOiVuaOru82Bipsz3gdPrJZZ6aCsoa6A2+B4v0b99gTqCY0ilZ2O36FUfNr0ggY3mx4p9J7P5MWnAAbU44soPbf/HXYBKH0THRcnPJm0IFNnAFVLanw3MA+lC7zs3iaCkOGTRqwDXDfQoeBBv8+l1bNgj8BczFMCYx/LNTprRN1hfQ6DSRr4OEjOfHcjv/E6laL2Pm5tPJH6zzln7gfGX0tFbLiVIr1mYx0gkGVtU5MIez/KOJKrFr1raOsOCxZeiG7npKCDfQ861AGVNW+fBANxaQK1igENHgEDkScGWFkbUe6uN7ZxTkfslglY9n8OvF8ZV2+qeDl2T+w+o3ZcNXMhCAC13IAnpYYsiTCzscsrpfoTcztMErVYEm58D0KaKCEeJDSdx9xVIss2oNtIFbDcuvyp9DfOT2UISEsmkf8B7ZP3j2p27YM8Jzf/EPFkr2/QzmY6p9y2P57W4ZBht/Q9FxdXCzaGPIyr5pG4woAuMcRrX7JM0ZNOdKcT7rRREU2bVzCPEo3T5q1ndFiN3lqIu9v0BApwqJs0lXy86yuojeisdPS7ipqqwtf0cW5E/UE5TCwfCoJphQbdX3rUcVYW2Jm/8WVGjX/Qf5G/1V4Szvo6mBT+HGJnQr/s6bbyNTwe4Dps0f7oc0Q/ddnRossylsiFXZi4G06cw2pUbWqrXJjWAeKxlxZYiu7YMKOcQrnkPPZpRH9MBrSAgt8nnEPOfrAjIFPa04srHAgesPtL8x5+d065nuJrfUOpxILpuB1BAjoraxG62bTjUA==
x-forefront-antispam-report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:BY3PR13MB5044.namprd13.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230016)(4636009)(39840400004)(136003)(396003)(376002)(346002)(366004)(6506007)(52536014)(33656002)(38070700005)(44832011)(53546011)(9686003)(41300700001)(86362001)(110136005)(478600001)(166002)(7696005)(316002)(966005)(71200400001)(45080400002)(55016003)(122000001)(38100700002)(66574015)(66556008)(186003)(76116006)(91956017)(5660300002)(66946007)(2906002)(66476007)(8676002)(8936002)(19627405001)(64756008)(66446008)(83380400001)(491001); DIR:OUT; SFP:1102;
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?utf-8?B?SWpxQ0xtekk0UXorY25xUDhDMjkxUXVHY09nbzl1Mm0xVUI2c1B6WmRzYmZ0?= =?utf-8?B?bUtGc2pqRnVrMU5JRytaS2VZVWdadHFrUnVBQytoY0JGc0RxMFNDakRXQ2Yz?= =?utf-8?B?LzBQaHlEc0hweVRGTU1rL1hhcWxmcE1HK2lJNExRQko5UHplSWcwWGFiblN1?= =?utf-8?B?cnRVSlpoUS93NmFXYitWZjlZUERpYzNzT1k2QTV2VStScTZqL01GVm15dDVq?= =?utf-8?B?NFpXU0RsSGdCUXJxY2JIUSt2Q3diYzdmdGhLYnVKcjBUMVdmeGhqYXF1M1Zq?= =?utf-8?B?MWMwWDg4cVB0emZQWFYxeVhrWXlJSEJqOHBQVjlWVExoMUFSNmE0R1FwaU8y?= =?utf-8?B?dzlRTmdOQVRlOHVVZTljdDR2ZlFMOUNwNWp2Z3ZkOHJiQTFvOERHTElvWlpy?= =?utf-8?B?QS9vZTdKRlF5SnhwYlRrQmU3RGtxazZmbU4xQ1RzR2QvUGdVT3NsN0NWbm9K?= =?utf-8?B?c3RkREUzU2VNY0NWcGxqY2ZjTWJDc052UmJLQTJ6WnRFV1MrakRPeFA1Zlh1?= =?utf-8?B?bTJZK29QN0MxRzFwWjBFdkZVOEh2VlFzQjR4d0pvSHA2SlJzaGRsQTVhcmxu?= =?utf-8?B?cmU2V0xhdGQ5YWZHWjVNYWlnSUdtLy9GMWZ1K3R6eUVocXN5SGxJT3JDdmZS?= =?utf-8?B?WXFMWllYOEltb3hya21kcFFtalVCYTFPcXlESzFKWGhUQTB1OVZOMlZ5ckxK?= =?utf-8?B?K2xrdGNmN2dsbXNEWGdLV0ZCbmdWZ1lvN0RRd08xQjFXcm9PdkFDTDQyak1n?= =?utf-8?B?Mk9XRUM0V2NJU0Z3MXV2U1J1VExsYS91aFp3ZnFoQnZRekhqT2dRT2lQdGxi?= =?utf-8?B?RHdYTFpBTWkvWDFOMCswejhIZ3ZmbmZEU1FsWjdhVGtxS0ZMUVBtVXcya1kz?= =?utf-8?B?ZW9JZDVDRGd1dkJRcTdySnFBT0tJeTFodFlzUldtSnJwV2EyQzFyelBsZXVO?= =?utf-8?B?VVZ1eWlYb3k1YlBxNWN3THNFVEZNRlNMSEpFT2pqbDlqWGd0ZTRHbjI1cmJk?= =?utf-8?B?YlVxWVFZRTA2TXRtS0UrVzNWUlJiZjFZZDBDcGRsZkNzdEovMWhXM2paQWRt?= =?utf-8?B?R1pUNERiak1CdTIrWnNHTlA1V3VWQUdSZVBsdXVabzIrTWlLZWpRTFMyVlI4?= =?utf-8?B?bnV0OWpUK05Wd0lEdEJ4ZXZza2N0UXJGd3F3UmpZckkySzJ5MGZVT3NSTks1?= =?utf-8?B?K1NKTDRYbXVSLzBkczVERUhxTW5tMFM1Uy9YV1BsWTZPMVFEQTVRcDVDczJr?= =?utf-8?B?TmRpUFBoZk81L0Y2cDB3NkI4M2FOcnFSTWpMR0tnL0ZBcnNFWEZCaU5KcTEv?= =?utf-8?B?L1JXWEw3aUxpWVM2VUM4NXo3RlplSXFmUks2K2YyNEc2bG81UzlpSmFRY1NU?= =?utf-8?B?S0E2YlYwOVM3cmVlUGdkVm5sUFRyTERUdGo0T3VxeGs0ZUxkMkwxd3JqVWJn?= =?utf-8?B?MWhoTnAwaVBPZWx5bzgxQWpqZk1KMHAzRkpKSDVmYWk1RnNZV0J6ZUFXZUN1?= =?utf-8?B?UVJvQnhQV2ViZHllUjFkVkxLdmUvSUxvVWkvSGJFb1YzYXFCekIxQ2ZaZitD?= =?utf-8?B?SHZZYmhTM2hRSHA0ZU1oMXhoUUpnZHY0RVdOOXh1cmlVWnRhdUEvNDBBdU80?= =?utf-8?B?N2RiM0FUWVhrZ0xhVnBDOGdiSDhUZ0daUWNMN1FLNzRvZTk0RzBycGExdlhu?= =?utf-8?B?aEQ5UCszUktjaGdsWEM5d3NuL3AvYzRWTm9DSjRFR3dYTVZUL3Vwd0twWGJh?= =?utf-8?B?TjBLckhHeEhnWC8xdDcxc0praW9EejdqVUtTZFV4NVJ4ZkNEUW44Qm9qdU95?= =?utf-8?B?T3JTYTMyMGJlaEkxQm1DT29xYVVTUDg0Q1ZUNFVhdjBSeklTMHhYMEtlUWww?= =?utf-8?B?d2FxK1VObkg3VXZtVlhZc3lUZTRnOUt1ZDV2c1c1Z2x6cjBqYVI0RGRHSWZw?= =?utf-8?B?R3o3MS9oeXQxaXJsT0VKYVJpc0Z6Tm1zRUdQM0U0eFhMR2NaOG1xWHBsemx5?= =?utf-8?B?NVRqZXBZZ0tsbUJONmhRVDBVR1dyWW9jdy93QlZ2MS8rOCtCUGw5eFkrWFJ6?= =?utf-8?B?ZFZ5Mm1Rend5RFBlQkc5SzloVmh6VWsvOEV2bHF3MWM5anlCYXVxeE5pK2Fa?= =?utf-8?B?RlVHckhtKzgrVXQ4cUhFMGh0NUtHZmxjS05zWFJRWUxtODk5NVB1cVZ3ZUVY?= =?utf-8?Q?21e+a+ZNlGn/TB6yM+Y0pjTfPciv8zbgKSFm6xEbylMK?=
Content-Type: multipart/alternative; boundary="_000_BY3PR13MB5044BA9C0C5F2E049997F750F2639BY3PR13MB5044namp_"
MIME-Version: 1.0
X-OriginatorOrg: Futurewei.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: BY3PR13MB5044.namprd13.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: e3226bce-aa69-49d7-935a-08da795de8fa
X-MS-Exchange-CrossTenant-originalarrivaltime: 08 Aug 2022 16:49:07.3533 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 0fee8ff2-a3b2-4018-9c75-3a1d5591fedc
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: T09NS0+48HDskDO2UEz/BpERGFYQYPDJs7VegOXmJT78yUkzYqKg+BtDFRJdC3E+vS6j2X0iKOf8s0Fv1aiIzw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW5PR13MB5416
Archived-At: <https://mailarchive.ietf.org/arch/msg/bier/UzkcGCVHRt1krMZtUTWJpX4OjA8>
Subject: Re: [Bier] Questions about draft-ietf-bier-te-ospfv3
X-BeenThere: bier@ietf.org
X-Mailman-Version: 2.1.39
Precedence: list
List-Id: "\"Bit Indexed Explicit Replication discussion list\"" <bier.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/bier>, <mailto:bier-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/bier/>
List-Post: <mailto:bier@ietf.org>
List-Help: <mailto:bier-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/bier>, <mailto:bier-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 08 Aug 2022 16:49:17 -0000

Hi Jeffrey,

    Thanks much for your further comments.
    My responses are inline below with [HC2].

Best Regards,
Huaimo
________________________________
From: Jeffrey (Zhaohui) Zhang <zzhang@juniper.net>
Sent: Sunday, August 7, 2022 9:53 AM
To: Huaimo Chen <huaimo.chen@futurewei.com>; 'bier@ietf.org' <bier@ietf.org>; draft-ietf-bier-te-ospfv3@ietf.org <draft-ietf-bier-te-ospfv3@ietf.org>; 'Toerless Eckert' <tte@cs.fau.de>
Subject: RE: Questions about draft-ietf-bier-te-ospfv3


Hi Huaimo,



Please see zzh> below.




Juniper Business Use Only

From: BIER <bier-bounces@ietf.org> On Behalf Of Huaimo Chen
Sent: Tuesday, July 5, 2022 10:27 PM
To: Jeffrey (Zhaohui) Zhang <zzhang@juniper.net>; 'bier@ietf.org' <bier@ietf.org>; draft-ietf-bier-te-ospfv3@ietf.org
Subject: Re: [Bier] Questions about draft-ietf-bier-te-ospfv3



[External Email. Be cautious of content]



Hi Jeffrey,



    Thank you very much for your questions.

    My answers are inline below with [HC].



Best Regards,

Huaimo

________________________________

From: Jeffrey (Zhaohui) Zhang <zzhang@juniper.net<mailto:zzhang@juniper.net>>
Sent: Tuesday, July 5, 2022 9:32 AM
To: 'bier@ietf.org' <bier@ietf.org<mailto:bier@ietf.org>>; draft-ietf-bier-te-ospfv3@ietf.org<mailto:draft-ietf-bier-te-ospfv3@ietf.org> <draft-ietf-bier-te-ospfv3@ietf.org<mailto:draft-ietf-bier-te-ospfv3@ietf.org>>
Subject: Questions about draft-ietf-bier-te-ospfv3



Hi Huaimo,

I am catching up some BIER reading and have some questions here. I am sorry if they have been raised and answered before - please just give me a link to the archive in that case.

I noticed that the WG version is not linked to draft-chen version.

[HC2]: We will ask others (IETF support? BIER chairs?) to fix this.

If I understand it correctly, BIER-TE BIFTs are not calculated but programmed based on planning. On each BFR, a bit-position is assigned to a link that is used for BIER-TE forwarding purposes, or to a "tunnel" that leads to a remote BFR (i.e., routed adjacency). That information is only useful locally (in the BIFT) and on the controller that determines the bitstring to use. Other BFRs won't use that.

[HC]: The bit-position assigned to a link is used for BIER-TE forwarding through BIER-TE BIFTs. It is also used for other purposes. For example, when we want to provide fast re-route protections against node and link failures for BIER-TE paths, a node as a PLR should know the bit-positions of the links on the other nodes such as the next hop and next next hop nodes.



Zzh> It would be good to point out the use cases for distributing the information via IGP: a) BFIRs finds out the bitstring by themselves instead of relying on controller; b) FRR.

[HC2]: I will update the draft accordingly.



Therefore, flooding that information in IGP does not seem to be useful (unless each BFIR determines on its own what BitString to use)? For the same reason, signaling MT/BAR/IPA information does not seem to be useful either. While https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Fdraft-ietf-bier-te-arch-13%23section-3.2.1&amp;data=05%7C01%7Chuaimo.chen%40futurewei.com%7C4ffe358070244f5f787e08da5e8ae5c1%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C637926247908948675%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=LzsTdOh3WmgUxFZRW3sn906JwsmkwuJrBRVROD5BoUQ%3D&amp;reserved=0<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2Fnam11.safelinks.protection.outlook.com%2F%3Furl%3Dhttps*3A*2F*2Fdatatracker.ietf.org*2Fdoc*2Fhtml*2Fdraft-ietf-bier-te-arch-13*23section-3.2.1%26data%3D05*7C01*7Chuaimo.chen*40futurewei.com*7C4ffe358070244f5f787e08da5e8ae5c1*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C0*7C637926247908948675*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C3000*7C*7C*7C%26sdata%3DLzsTdOh3WmgUxFZRW3sn906JwsmkwuJrBRVROD5BoUQ*3D%26reserved%3D0__%3BJSUlJSUlJSUlJSUlJSUlJSUlJSUlJSU!!NEt6yMaO-gk!B5bLqVAwl6tt2cY5ovMRS3TzxGueCiVPVlYIFnJOiHyKob1gt-qViY1o0v0ujGKgYAgsLwfsBakDrTPzIftbfnzG%24&data=05%7C01%7Chuaimo.chen%40futurewei.com%7C7cc69dd0047d48279dbe08da787c3672%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C637954772163512647%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=zB1Gl7eI7R%2F6l0yS4GIxtxa2t2saUGJE1Fov2%2B4gba4%3D&reserved=0> does not preclude distributed model (e.g., each BFIR determines on its own what BitString to use to identify a tree), it does not seem to be an expected scenario; if this document intends to address that it should be made clear.

[HC]:  Refer to the answer above.

Zzh> What about MT/BAR/IPA fields 😊

[HC2]: These may be used for computing P2MP paths.

It seems to me that the information should be signaled from a controller/orchestrator directly to targeted individual BFRs using other Netconf/PCEP/BGP.

[HC]: It seems that using a controller to assign/configure bit positions of the links on each of BFRs is OK. But using IGP to distribute the bit positions is more efficient after the bit positions are assigned/configured on the links of a node.



Zzh> It’s ok to use IGP but it is not necessarily more efficient. The bit position assignment is centrally planned and done (unlike the local MPLS labels) and all BFRs need to have the same information and that does not change with node/link up/down. Each BFR needs to learn its own bit position information “out of band” anyway (can’t be through IGP), so it may actually be better for it to learn all information “out of band” in the SDN era (in the old days it is indeed better for each router to learn its own information and then flood). Having said that, this is not to say that we must not use IGP.

Besides that, the signaling in the draft does not cover "routed adjacency". For the direct p2p links, it assumes different bits are assigned for the two BFRs connected by the link. However, that is different from the following in BIER-TE arch spec:

5.1.1.  P2P Links

   On a P2P link that connects two BFRs, the same bit position can be
   used on both BFRs for the adjacency to the neighboring BFR.  A P2P
   link requires therefore only one bit position.
[HC]: We will consider this.

Zzh> I talked about both routed adjacency and one bit position for p2p links (just want to make sure).

[HC2]: This draft just distributes the bit position configured on a link.  For p2p links, whether one bit position is used for one p2p link or not, seems out of scope of this draft.

For routed adjacency, I will update the draft to include this case.


Zzh> Thanks.

Zzh> Jeffrey

It is also not clear if BIFT-ID ranges need to be signaled (so that when BFR1 sends traffic to BFR2 according to the programmed BIFT, it knows what BIER label to use). I assume the BIFT-IDs (to be used to reach a neighbor) can also be signaled from the controller as part of local BIFT entries?

[HC]: Using IGP to distribute/signal BIFT-ID ranges seems more efficient than using the controller.

Thanks.

Jeffrey


Juniper Business Use Only