Re: [Idr] Please discuss the use cases for draft-xie-idr-mpbgp-extention-4map6

Hi Robert,

I understand that VPN4 is about encapsulation.  As mentioned before, the new extension in my draft focuses on the case of IPv4 delivery over multi-domain IPv6-only underlay network, it can support not only IPv4/IPv6 encapsualtion, but also IPv4/IPv6 translation simultaneously. Translation is important transition mechanism, it has been widely developed.  From the perspective of an operator, it is better for a unified control plane to support all possible functions at the data plane. Further more, address mapping mechanism from IPv4 to IPv6 has several advantages for network operation, which have been discussed before.

Thank you very much.

Chongfeng

From: Robert Raszuk
Date: 2024-03-11 00:23
To: Chongfeng Xie
CC: ketant.ietf; idr
Subject: Re: [Idr] Please discuss the use cases for draft-xie-idr-mpbgp-extention-4map6
Hi Chongfeng,

> It adopts address mapping rule which is the 1:1 mapping between IPv4 address and IPv6 address

Let's assume that you are talking about prefixes not actual addresses as this is what draft says. 

But I have a fundamental question as an alternative to this proposal: 

Why not to use VPNv4 with IPv6 next hops as is without changing anything in the protocols or shipping implementations ? 

At min please kindly document pros and cons of using VPN signalling to accomplish the very same outcome.  For transport as you know VPNs can run over lot's of data plane options: IPv6, SRv6 etc ... 

Note that if you would not propose a new SAFI I could see some benefits to what you are after ... but you do hence we better very well understand the reason for this extra dev and ops cost. 

Many thx,
Robert

On Sun, Mar 10, 2024 at 9:40 AM Chongfeng Xie <chongfeng.xie@foxmail.com> wrote:

Hi Ketant,

Sorry for my negligence of your mail accidentally. Actually your question has been discussed early last year.  I try to answer it again as below，

As mentioned The use case of 4map6 proposal in this draft is to support IPv4aaS in the multi-domain IPv6-only networks.  It adopts address mapping rule which is the 1:1 mapping between IPv4 address and IPv6 address, and IPv4 address become part of IPv6 address. With this design，PE devices can map the source and destination addresses of IPv4 packets to the source addresses of outer IPv6 packets, respectively.  It mainly meets the following requirements:

1）Compatibility with both encapsulation and translation, as we all know, IPv4 service delivery over IPv6 network has two transition approaches: Encapsulation and translation,  both of them have been used in current networks. 4map6 proposal can meet their needs simultaneously. Especially in translation, it can support both doulbe translation and single translation.

2）Security，the outer IPv6 address is dynamically generated based on mapping, and does not require a statically configured address as the tunnel endpoint address in advance.  This will be helpful to avoid the static IPv6 address from becoming the target of the DDOS attack.

3）Load balancing，the 4map6 proposal assigns a corresponding IPv6 address to each host's IPv4 address in the IPv6 network, and the IPv6 address newly generated can more accurately identify the host. This allows for IPv6 address based load balancing and management of the host in the IPv6 network based on the IPv6 address.

 I hope this explanation can address your concerns. Welcome to continue the discussion.

Best regards
Chongfeng

chongfeng.xie@foxmail.com

From: Ketan Talaulikar
Date: 2024-02-12 22:57
To: Chongfeng Xie; draft-xie-idr-mpbgp-extension-4map6
CC: jhaas; Susan Hares; idr
Subject: Re: [Idr] Please discuss the use cases for draft-xie-idr-mpbgp-extention-4map6
Hi Chongfeng/Authors,

Thanks for your updates to the document. 

I am still struggling to find the answer to the question on why it is necessary to perform mapping from IPv4 to IPv6 and then back to IPv4 when providing IPv4 connectivity service over an IPv6 core? Why is it not sufficient to simply encapsulate the IPv4 payload into any encapsulation (e.g., IPv4-in-IPv6, SRv6, MPLS, GRE, etc.) using RFC8950 encoding for the IPv4 unicast/VPN SAFI. These solutions are documented in draft-mishra-idr-v4-islands-v6-core-4pe

Perhaps I am missing something and it would help me understand the need for such mapping by service provider PE routers.

Thanks,
Ketan

On Thu, Feb 8, 2024 at 5:14 AM Chongfeng Xie <chongfeng.xie@foxmail.com> wrote:

Hi Jeff,

We have submitted a new version of draft-xie-idr-mpbgp-extention-4map6. Based on your suggestions, the contents of new attribute is placed in a new TLV in the tunnel encapsulation attribute of RFC9012, and the format of the NLRI is revised as well. In addition, the section of operation has been changed accordingly. 

        Name:     draft-xie-idr-mpbgp-extension-4map6
        Revision: 09
        Title:    MP-BGP Extension and the Procedures for IPv4/IPv6 Mapping Advertisement
        Date:     2024-02-09
        Group:    idr
        Pages:    16
        URL: https://www.ietf.org/archive/id/draft-xie-idr-mpbgp-extension-4map6-09.txt
        Status: https://datatracker.ietf.org/doc/draft-xie-idr-mpbgp-extension-4map6/
        HTMLized: https://datatracker.ietf.org/doc/html/draft-xie-idr-mpbgp-extension-4map6
        Diff: https://author-tools.ietf.org/iddiff?url2=draft-xie-idr-mpbgp-extension-4map6-09

We express sincere thanks to you for reviewing the draft as WG chair and providing a couple of important suggestions.  We also thank idr WG for the comments and suggestions received so far. 

If you have any new comments or suggestions, please feel free to let me know. Thanks!

Best regards
Chongfeng   

From: 【外部账号】Jeffrey Haas
Date: 2024-02-05 00:02
To: Chongfeng Xie
CC: Sue Hares; idr; draft-xie-idr-mpbgp-extension-4map6
Subject: Re: [Idr] Please discuss the use cases for draft-xie-idr-mpbgp-extention-4map6
Chongfeng,

On Jan 29, 2024, at 10:38 AM, Chongfeng Xie <chongfeng.xie@foxmail.com> wrote:
Based on your comment and suggestions, we have made the following revisions and submitted a new version, 

[...]

If you have any further comments, please feel free to let me know. 

Your changes significantly address my operational concerns.  Thank you.

-- Jeff

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