Re: [Lsr] 回复: New Version Notification for draft-zhu-lsr-isis-sr-vtn-flexalgo-01.txt

Yongqing,

I have two basic comments:

1. Using L2 Bundle Member Attributes TLV for advertising attributes for 
VTNs seems like a hack.

2.

   "In order to correlate the virtual or physical member links with the
    corresponding VTNs, each member link SHOULD be assigned with a
    dedicated Admin Group or Extended Admin Group, which is included in
    the definition of the Flex-Algo of the corresponding VTN.  Note that
    in this case the Admin Group or Extended Admin Group of the Layer 3
    link SHOULD be set to the union of all the Admin Groups or Extended
    Admin Groups of its virtual or physical member links.  This is to
    ensure that the Layer 3 link is always included in the Flex-Algo
    specific constraint path computation of the VTNs it participates in."

Above proposal does not work. Here's the simple example:

Flex-algo 128, FAD include RED
Flex-algo 129, FAD exclude RED

Now you have two VTNs, one for FA 128 (VT1) and one for 129 (VT2).

So your VT1 member link will have affinity RED and your VT2 will not 
have any affinity set (I presume).

Your L3 will have affinity RED set based on your proposal. As a result 
the L3 link will be be excluded for FA 129, but that is not what you 
want, because your VTN2 does not have affinity RED set.

The fundamental problem is that FA works on L3 data only. You are trying 
to make it work for L2, but that is not going to work.

thanks,
Peter

On 16/09/2020 08:13, zhuyq8@chinatelecom.cn wrote:
> Hi WG,
> 
> We just submitted a new revision of draft-zhu-lsr-isis-sr-vtn-flexalgo. This document specifies a mechanism to use Flex-Algo together with small extensions to IS-IS L2 bundle to distribute the topology and resource attribute of SR based VTN. Your review and comments are appreciated.
> B.R.
> Zhu Yongqing
> 
> -----邮件原件-----
> 发件人: internet-drafts@ietf.org <internet-drafts@ietf.org>
> 发送时间: 2020年9月11日 17:11
> 收件人: Dongjie (Jimmy) <jie.dong@huawei.com>; Yongqing Zhu <zhuyq8@chinatelecom.cn>; Huzhibo <huzhibo@huawei.com>
> 主题: New Version Notification for draft-zhu-lsr-isis-sr-vtn-flexalgo-01.txt
> 
> 
> A new version of I-D, draft-zhu-lsr-isis-sr-vtn-flexalgo-01.txt
> has been successfully submitted by Jie Dong and posted to the IETF repository.
> 
> Name:           draft-zhu-lsr-isis-sr-vtn-flexalgo
> Revision:       01
> Title:          Using Flex-Algo for Segment Routing based VTN
> Document date:  2020-09-11
> Group:          Individual Submission
> Pages:          8
> URL:            https://www.ietf.org/id/draft-zhu-lsr-isis-sr-vtn-flexalgo-01.txt
> Status:         https://datatracker.ietf.org/doc/draft-zhu-lsr-isis-sr-vtn-flexalgo/
> Htmlized:       https://datatracker.ietf.org/doc/html/draft-zhu-lsr-isis-sr-vtn-flexalgo
> Htmlized:       https://tools.ietf.org/html/draft-zhu-lsr-isis-sr-vtn-flexalgo-01
> Diff:           https://www.ietf.org/rfcdiff?url2=draft-zhu-lsr-isis-sr-vtn-flexalgo-01
> 
> Abstract:
>     As defined in I-D.ietf-teas-enhanced-vpn, enhanced VPN (VPN+) aims to
>     provide enhanced VPN service to support the needs of enhanced
>     isolation and stringent performance requirements.  VPN+ requires
>     integration between the overlay VPN and the underlay network.  A
>     Virtual Transport Network (VTN) is a virtual network which consists
>     of a subset of network topology and network resources allocated from
>     the underlay network.  A VTN could be used as the underlay for one or
>     a group of VPN+ services.
> 
>     I-D.dong-lsr-sr-enhanced-vpn defines the IGP mechanisms with
>     necessary extensions to build a set of Segment Routing (SR) based
>     VTNs.  This document describes a simplified mechanism to build the SR
>     based VTNs using SR Flex-Algo together with minor extensions to IGP
>     L2 bundle.
> 
> 
> 
> 
> 
> Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at tools.ietf.org.
> 
> The IETF Secretariat
> 
> 
> 
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