Re: [bess] Encoding a 20 bit label in a 24 bit field.

Hi Stephane, 
No objection - I think the question on whether BOS should be encoded in those bits confirms that this should be specified. 
Thanks,
Acee

On 10/22/18, 9:47 AM, "BESS on behalf of stephane.litkowski@orange.com" <bess-bounces@ietf.org on behalf of stephane.litkowski@orange.com> wrote:

    Hi,

    Does anyone disagree with the additional Jakob's statement proposal ?
    " The lower order 4 bits SHOULD be sent as 0 and ignored on receipt."

    As an example, in MVPN for PMSI tunnel attribute, we have the following statement which does not tell anything about the lower order bits:
    " If the MPLS Label field is non-zero, then it contains an MPLS label
       encoded as 3 octets, where the high-order 20 bits contain the label
       value.  Absence of an MPLS Label is indicated by setting the MPLS
       Label field to zero."

    Brgds,

    -----Original Message-----
    From: BESS [mailto:bess-bounces@ietf.org] On Behalf Of Ali Sajassi (sajassi)
    Sent: Tuesday, October 16, 2018 19:30
    To: Jakob Heitz (jheitz); Zhuangshunwan; BESS
    Subject: Re: [bess] Encoding a 20 bit label in a 24 bit field.

    Yes, just the encoding of label value needs to be clear. 

    Cheers,
    Ali

    On 10/15/18, 6:24 PM, "BESS on behalf of Jakob Heitz (jheitz)" <bess-bounces@ietf.org on behalf of jheitz@cisco.com> wrote:

        How about:
        The lower order 4 bits SHOULD be sent as 0 and ignored on receipt.

        Regards,
        Jakob.

        -----Original Message-----
        From: Zhuangshunwan <zhuangshunwan@huawei.com> 
        Sent: Monday, October 15, 2018 6:02 PM
        To: Jakob Heitz (jheitz) <jheitz@cisco.com>; BESS <bess@ietf.org>
        Subject: RE: Encoding a 20 bit label in a 24 bit field.

        It is good to make this explicit. This ambiguity has led to some unnecessary interworking problems.

        Should we also need to explicitly define the "bottom of stack" bit in the low-order bit of the 3-octet label field?

        Thanks,
        Shunwan

        -----Original Message-----
        From: BESS [mailto:bess-bounces@ietf.org] On Behalf Of Jakob Heitz (jheitz)
        Sent: Tuesday, October 16, 2018 4:21 AM
        To: BESS <bess@ietf.org>
        Subject: [bess] Encoding a 20 bit label in a 24 bit field.

        We have proposed the following erratum for RFC 7432.

        Opinions?

        Regards,
        Jakob.

        -----Original Message-----
        From: RFC Errata System <rfc-editor@rfc-editor.org>
        Sent: Friday, October 12, 2018 12:37 PM
        To: Ali Sajassi (sajassi) <sajassi@cisco.com>; raggarwa_1@yahoo.com; nabil.n.bitar@verizon.com; aisaac71@bloomberg.net; uttaro@att.com; jdrake@juniper.net; wim.henderickx@alcatel-lucent.com; db3546@att.com; aretana.ietf@gmail.com; martin.vigoureux@nokia.com; Giles Heron (giheron) <giheron@cisco.com>; nabil.n.bitar@verizon.com
        Cc: Krishnamoorthy Arumugham (karumugh) <karumugh@cisco.com>; l2vpn@ietf.org; rfc-editor@rfc-editor.org
        Subject: [Technical Errata Reported] RFC7432 (5523)

        The following errata report has been submitted for RFC7432, "BGP MPLS-Based Ethernet VPN".

        --------------------------------------
        You may review the report below and at:
        http://www.rfc-editor.org/errata/eid5523

        --------------------------------------
        Type: Technical
        Reported by: Krishnamoorthy Arumugham <karumugh@cisco.com>

        Section: 7

        Original Text
        -------------
        Clarifications to following sub-sections:
        Section 7.1
        Section 7.2
        Section 7.5

        Corrected Text
        --------------
        Section 7.1:
        Add below text to the section 7.1 regarding the encoding of MPLS label:

        "The value of the 20-bit MPLS label is encoded in the high-order 20 bits of the 3 bytes MPLS Label field."

        Section 7.2:
        Add below text to the section 7.2 regarding the encoding of both the MPLS label fields:

        "The value of the 20-bit MPLS label is encoded in the high-order 20 bits of the 3 bytes MPLS Label field for both MPLS Label1 and MPLS Label2."

        Section 7.5:
        Add below text to the section 7.5 regarding the encoding of ESI Label fields:

        "The value of the 20-bit MPLS label is encoded in the high-order 20 bits of the ESI Label field."

        Notes
        -----
        MPLS label is a 20-bit value and is stored in a 3 bytes field in a packet. The 20-bit MPLS label value is generally stored in higher order 20 bits of the 3 byte label field. The exact encoding to be followed for storing MPLS label values are not explicitly mentioned in the RFC 7432 under section 7.1, 7.2 and 7.5 for different types of EVPN routes. This lead to ambiguity in different implementations. Hence a clarification is required.

        Instructions:
        -------------
        This erratum is currently posted as "Reported". If necessary, please
        use "Reply All" to discuss whether it should be verified or
        rejected. When a decision is reached, the verifying party  
        can log in to change the status and edit the report, if necessary. 

        --------------------------------------
        RFC7432 (draft-ietf-l2vpn-evpn-11)
        --------------------------------------
        Title               : BGP MPLS-Based Ethernet VPN
        Publication Date    : February 2015
        Author(s)           : A. Sajassi, Ed., R. Aggarwal, N. Bitar, A. Isaac, J. Uttaro, J. Drake, W. Henderickx
        Category            : PROPOSED STANDARD
        Source              : Layer 2 Virtual Private Networks
        Area                : Routing
        Stream              : IETF
        Verifying Party     : IESG

        _______________________________________________
        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

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

    _________________________________________________________________________________________________________________________

    Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc
    pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler
    a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration,
    Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci.

    This message and its attachments may contain confidential or privileged information that may be protected by law;
    they should not be distributed, used or copied without authorisation.
    If you have received this email in error, please notify the sender and delete this message and its attachments.
    As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified.
    Thank you.

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