Re: [Bier] Questions on draft-zhang-bier-te-yang

[<[e-mail]>]

Hi Ben,






Thank you very much for your comments!


Please find my answer below with [Sandy].






Thanks,


Sandy







原始邮件



发件人：benjaminr <[e-mail]>
收件人：BIER WG <[e-mail]>;
日 期 ：2019年05月09日 22:44
主 题 ：[Bier] Questions on draft-zhang-bier-te-yang


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Hi,


 


Authors, please clarify the below questions.


 


      module: ietf-bier-te


        augment /rt:routing:


          +--rw bier-te


             +--rw subdomain* [subdomain-id]


                +--rw subdomain-id    uint16


                +--rw te-adj-id


                |  +--rw si* [si]


                |     +--rw si     uint16


                |     +--rw adj* [adj-id]


                |        +--rw adj-id     uint16


                |        +--rw adj-if     if:interface-ref


                |        +--rw bp-type?   Enumeration // BEN1


BEN1//


Bp-type is the property of interface and I think the bp-type will not change (or) need to be configured for each SD.


Example: bp-type of an interface is p2p no matter the SD ?


Considering this, can we remove this config under SD and instead define this bp-type configuration under bier-te/adj-if


This means, a hierarchy like “bier-te/adj-if/bp-type”.


[Sandy] The BIER-TE's BP is different with BIER. The BP of BIER-TE should under SD and SI. Please find the description in the first paragraph, section 1 in "draft-ietf-bier-te-arch-01".


"




 The Bit Index Forwarding Table (BIFT) exists in every BFR. For every
 subdomain in use, it is a table indexed by SI:BitPosition and is
 populated by the BIER-TE control plane. Each index can be empty or
 contain a list of one or more adjacencies.
"



 


                +--rw bsl* [fwd-bsl]


                |  +--rw fwd-bsl    uint16


                |  +--rw si* [si]


                |     +--rw si            uint16


                |     +--rw te-bift-id


                |     |  +--rw type?    enumeration


                |     |  +--rw value    rt-types:mpls-label


                |     +--rw fwd-items* [te-bp]


                |        +--rw te-bp       uint16


                |        +--rw bp-type?    enumeration // BEN2


BEN2//


Fwd-items need not have bp-type. I think there is no use of this field in forwarding. Can this be removed ?


[Sandy] It is inherent from the adjacency's BP. If the router is total controlled by controller, the forwarding table can be delivered to router directly with no per adjacency BP configuration. 


So IMO it can be showed here though it may not be used in forwarding.


                |        +--rw (fwd-type)


                |        |  +--:(connected)


                |        |  +--:(routed)


                |        |  +--:(local-decap)


                |        |  +--:(other)


                |        +--rw dnr-flag?   boolean


                |        +--rw out-info //BEN3


BEN3//


 


“Section 3.6. Requirements”  of draft-ietf-bier-te-arch-01:


“BIER-TE forwarding MAY support more than one adjacency on a bit and


ECMP adjacencies.”


 


It is advantageous to have a single bit position mapped to more than one adjacency.


So the fields like out-info, fwd-type, dnr-flag etc need to be grouped to a container, and there can be a list of this container under te-bp.


[Sandy] I agree with you that in some circumstances the same BP can be used for multiple links. 


IMO the simplest modification is that change the leaf "out-info" to list, like out-info [if-index].


How do you think about it?



 


                |        |  +--rw fwd-intf          if:interface-ref


                |        |  +--rw te-out-bift-id


                |        |     +--rw type?    enumeration


                |        |     +--rw value    rt-types:mpls-label


                |        +--rw te-frr {bier-te-frr}?


                |        |  +--rw frr-index?      uint16


                |        |  +--rw resetbitmask* [bitmask]


                |        |     +--rw bitmask    bit-string


                |        +--rw te-ecmp* [out-if] {bier-te-ecmp}?


                |           +--rw out-if            if:interface-ref


                |           +--rw te-out-bift-id


                |              +--rw type?    enumeration


                |              +--rw value    rt-types:mpls-label


 


 


 


 


Thanks


Benjamin R


VRP PDU, Network Business Line


Huawei Technologies India Pvt. Ltd.


Survey No. 37, Next to EPIP Area, Kundalahalli, Whitefield


Bengaluru-560066, Karnataka


Tel: + 91-80-49160700 Ext II Mob: [phone] Email: [e-mail]


  


 


 


 
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