IETF Logo Mail Archive

Re: [mpls] [Bier] Encapsulation first nibble

Gregory Mirsky <gregory.mirsky@ericsson.com> Tue, 17 March 2015 17:45 UTC

Return-Path: <gregory.mirsky@ericsson.com>
X-Original-To: mpls@ietfa.amsl.com
Delivered-To: mpls@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id AE9471A8828; Tue, 17 Mar 2015 10:45:39 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -104.201
X-Spam-Level:
X-Spam-Status: No, score=-104.201 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, USER_IN_WHITELIST=-100] autolearn=ham
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 fsrgUYJDDiCR; Tue, 17 Mar 2015 10:45:37 -0700 (PDT)
Received: from usevmg20.ericsson.net (usevmg20.ericsson.net [198.24.6.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 225FE1A00F4; Tue, 17 Mar 2015 10:45:37 -0700 (PDT)
X-AuditID: c618062d-f79686d0000030a8-01-550812dfb6f3
Received: from EUSAAHC008.ericsson.se (Unknown_Domain [147.117.188.96]) by usevmg20.ericsson.net (Symantec Mail Security) with SMTP id C1.BE.12456.FD218055; Tue, 17 Mar 2015 12:41:19 +0100 (CET)
Received: from EUSAAMB103.ericsson.se ([147.117.188.120]) by EUSAAHC008.ericsson.se ([147.117.188.96]) with mapi id 14.03.0210.002; Tue, 17 Mar 2015 13:45:35 -0400
From: Gregory Mirsky <gregory.mirsky@ericsson.com>
To: Antoni Przygienda <antoni.przygienda@ericsson.com>, Xuxiaohu <xuxiaohu@huawei.com>, "stbryant@cisco.com" <stbryant@cisco.com>, Eric C Rosen <erosen@juniper.net>, BIER <bier@ietf.org>
Thread-Topic: [Bier] Encapsulation first nibble
Thread-Index: AQHQXcZrqojq7Dn2dkqRctiyZ05xTp0aTR0AgAY0PqCAAAkpwIAAqO6A///CXeA=
Date: Tue, 17 Mar 2015 17:45:35 +0000
Message-ID: <7347100B5761DC41A166AC17F22DF1121B92F9DC@eusaamb103.ericsson.se>
References: <55033E87.3030305@juniper.net> <5503403E.4050304@cisco.com> <1FEE3F8F5CCDE64C9A8E8F4AD27C19EE0831CB77@NKGEML512-MBS.china.huawei.com> <1FEE3F8F5CCDE64C9A8E8F4AD27C19EE0831CBB2@NKGEML512-MBS.china.huawei.com> <2E4BB27CAB87BF43B4207C0E55860F1827D3C5@eusaamb103.ericsson.se>
In-Reply-To: <2E4BB27CAB87BF43B4207C0E55860F1827D3C5@eusaamb103.ericsson.se>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [147.117.188.10]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpgkeLIzCtJLcpLzFFi42KZXLonQfe+EEeowb1/ehZLZ+xhsli34QOz xa2lK1ktnjzYym5x7ukcRout51cxOrB5TPm9kdWj5chbVo8lS34yeVxvusoewBLFZZOSmpNZ llqkb5fAlXHy6BaWgt98Fben/GBrYJzC08XIySEhYCLxa+0SJghbTOLCvfVsXYxcHEICRxgl Tu76zw7hLGeUuDTxPAtIFZuAkcSLjT1gCRGBA4wSnUcegyWYBZwkGpZfZgSxhQX0JM5vecwG YosI6EssP3+NFcL2k3jQdhGsnkVAVeLPkj9Agzg4eAV8JbqOV0IsW8gk8Wn7ObAaTgEfief9 x8BsRqDzvp9awwSxS1zi1pP5UGcLSCzZc54ZwhaVePn4HyuErSQxaek5Voh6HYkFuz+xQdja EssWvgar5xUQlDg58wnLBEaxWUjGzkLSMgtJyywkLQsYWVYxcpQWp5blphsZbGIERtkxCTbd HYx7XloeYhTgYFTi4TXQYA8VYk0sK67MPcQozcGiJM676MHBECGB9MSS1OzU1ILUovii0pzU 4kOMTBycUg2MbdxapbyZO84WLDxWfm+z1pZokfuWX6sVGYQ+b775MVanYdePnQxbOr5LZyic 0tiQ9tf25j6R5ayK2uzCNcV/fvr8UO35vvjxx7mnnzxoSbp5odPN8EmqxAbmkon3FNlOW66b r2xfW/vm1F1GGWXtG6tfJbu2Nt5n/tB4RYw5g7M7dqqOc+B/JZbijERDLeai4kQAxZFq9JMC AAA=
Archived-At: <http://mailarchive.ietf.org/arch/msg/mpls/rOtSwLBNRNqM4V2NZSzLLZoHAEU>
Cc: "mpls@ietf.org" <mpls@ietf.org>, "sfc@ietf.org" <sfc@ietf.org>
Subject: Re: [mpls] [Bier] Encapsulation first nibble
X-BeenThere: mpls@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Multi-Protocol Label Switching WG <mpls.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/mpls>, <mailto:mpls-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/mpls/>
List-Post: <mailto:mpls@ietf.org>
List-Help: <mailto:mpls-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/mpls>, <mailto:mpls-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 17 Mar 2015 17:45:39 -0000

Hi Tony,
as Eric pointed, the potential problem is with non-BIER LSRs and all BIER LSRs do interpret BIER application label. Thus non-BIER transit LSR may look past the label stack to balance flows across available ECMP. And if the very first nibble is 0x04 or 0x06 (which may happen for Destination MAC as discussed in EVPN scenarios), the LSR will interpret the packet as IPv4 or IPv6 respectively and thus potentially cause out-of-order packets within the same flow resulting from the hashing on something which is not IP 5 tuple.
Another possible solution, IMHO, may be use of PWMCW as discussed in Section Frame Ordering RFC 7432.

	Regards,
		Greg

-----Original Message-----
From: mpls [mailto:mpls-bounces@ietf.org] On Behalf Of Antoni Przygienda
Sent: Tuesday, March 17, 2015 10:16 AM
To: Xuxiaohu; stbryant@cisco.com; Eric C Rosen; BIER
Cc: mpls@ietf.org; sfc@ietf.org
Subject: Re: [mpls] [Bier] Encapsulation first nibble

Not being much of an encapsulation, data plane guy myself, I wonder a tad how hacky those 'heuristics' are.  Last label indicates clearly a BIER header is following. For the LSRs that do not support BIER and do not parse the BIER encaps there is no reason to look 'behind the label'.  Multiple sub-domains allow for clean separation of traffic with different properties if needed and with that there is even less reason for some kind of 'heuristic' DPI

Now, given some 'heuristics' are in place no matter what value we put into the nibble, sooner or later we'll collide with it no matter what value we pick since such 'heuristics' basically try to parse bits without understanding their context and with that can easily mistake an 'eye' for an 'I' or an 'aye'. 

--- tony 



_______________________________________________
mpls mailing list
mpls@ietf.org
https://www.ietf.org/mailman/listinfo/mpls

v2.23.0 | Report a Bug | By Email