[bess] Document shepherd's review of draft-ietf-bess-evpn-na-flags-03

[Bocci, Matthew (Nokia - GB)]

Authors

I am the document shepherd for this draft. Please see below for my comments. 
Please treat these as you would any other WG last call comments.

Best regards

Matthew

General:
Why do you say the EVPN ARP/ND Extended Community is optional? Don’t you always 
use it if you comply to the procedures in the draft? Also, I am not clear why 
in section 3 you say the PE will follow the procedures (which I interpret as a 
MUST), but there are no MUSTs in e.g. 3a.

Please clarify in the draft.

Please also check the capitalization of RFC2119 keywords throughout. For 
example, there are a few instances where a 'may' should be a 'MAY'

Abstract and 1. Introduction
This document proposes an OPTIONAL extended community that is
   advertised ...

Change to 'this document defines an extended community..."


Section 1.1 Terminology and Conventions:
"Address Resolution Protocol (ARP) Requests or Neighbor Discovery (ND) - or 
Neighbor Solicitation (NS) - messages are replied locally by the PE,"
This text seems to mix up Neighbor Discovery (the process) with Neighbor 
Solicitation (the message). I would suggest deleting Neighbor Discovery from 
this sentence.

1. Use of the EVPN ARP/ND Extended Community

A PE may learn the IPv6->MAC pair and its associated ND Flags in the management 
plane or snooping Neighbor Advertisement messages coming from the CE.

s/management plane or snooping Neighbor/management plane or by snooping Neighbor

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Re: [bess] [Idr] [Softwires] Regarding the Next Hop Network Address coding for IPv4 VPN over IPv6 Core in RFC5549

[Alexander Okonnikov]

Hi Robert,

Sorry, I was not so precise :-) Of course, RD part in Next Hop is not copied 
from RD of NLRI, but zeroed. I was trying to explain why Next Hop field in RFC 
4364 and RFC 4659 has format RD:IP (VPNvX address) rather than just IP.

Thank you!

> 26 июня 2019 г., в 16:27, Robert Raszuk  написал(а):
> 
> Hi Alex,
> 
> > My understanding is follow: RD is encoded in Next Hop field  
> 
> That is subtle misinterpretation of the 4364 :) 
> 
> The text says: 
> 
> "When a PE router distributes a VPN-IPv4 route via BGP, it uses its  own 
> address as the "BGP next hop".  This address is encoded as a VPN-IPv4 address 
> with an RD of 0."
> 
> That can be read as: 
> 
> A) Next hop field has prepended zeros to match the NLRI format of 8 octet RD 
> + 4 octet IPv4 (for IPv4 case) 
> 
> B) Next hop is of format RD:IPv4 where RD=0
> 
> My recollection and number of direct discussions with authors of 
> both2547/4364 & 4760 at that time leads me to believe we are dealing with A. 
> Of course anyone can see option B as valid, but at the end of the day it is 
> the same on the wire :) 
> 
> So I am not sure what exactly the problem or the question we are trying to 
> answer is :) 
> 
> Cheers,
> R.
> 
> 
> 
> 
> 
> 
> On Wed, Jun 26, 2019 at 3:22 PM Alexander Okonnikov 
> mailto:alexander.okonni...@gmail.com>> wrote:
> Hi,
> 
> My understanding is follow: RD is encoded in Next Hop field, because authors 
> of RFC 4364, while referring to RFC 2858, were trying to make it consistent 
> with RFC 4760 (obsoletes RFC 2858). RFC 2858 says that Next Hop field should 
> match AFI. On the other hand, RFC 4760 says that Next Hop Field should match 
> combination of AFI/SAFI. Also, drafts of RFC 4364 and RFC 4760 were being 
> developed practically at the same time period.
> 
>> 26 июня 2019 г., в 16:05, UTTARO, JAMES > > написал(а):
>> 
>> +1
>>  
>> From: Idr mailto:idr-boun...@ietf.org>> On Behalf Of 
>> Robert Raszuk
>> Sent: Wednesday, June 26, 2019 7:53 AM
>> To: Xiejingrong mailto:xiejingr...@huawei.com>>
>> Cc: i...@ietf.org ; ian.far...@telekom.de 
>> ; ianfar...@gmx.com 
>> ; softwi...@ietf.org ; 
>> bess@ietf.org 
>> Subject: Re: [Idr] [bess] [Softwires] Regarding the Next Hop Network Address 
>> coding for IPv4 VPN over IPv6 Core in RFC5549
>>  
>> All,
>>  
>> RD is a property of the NLRI not next hop. I am not sure where in this 
>> thread or some spec someone came to the conclusion that next hop field 
>> should contain an RD. RD is not useful there and should never be part of any 
>> next hop field. 
>>  
>> Remember RD role is to make prefix unique - that's it - no more no less. 
>> Next hop uniqness is given by architecture and there is no need to make it 
>> unique. 
>>  
>> In some cases when we need to carry IPv4 address in IPv6 next hop field 
>> (there was historically some assumption that next hop must be of the same AF 
>> as prefix) we prepend to it numerical zeros.
>>  
>> Thx,
>> R.
>>  
>>  
>>  
>>  
>>  
>> On Wed, Jun 26, 2019 at 1:40 PM Xiejingrong > > wrote:
>> Hi folks,
>>  
>> I guess this is an inconsistency due to past carelessness. Is there anyone 
>> can tell us the history of this inconsistency ?
>> RFC4364(VPNv4 over IPv4 network) and RFC4659(VPNv6 over IPv4 or IPv6 
>> network) both require to use RD+IP(v4 or v6 respectively) as nexthop.
>> RFC5549(VPNv4/IPv4 over IPv6 network) requires to use IPv6 without RD as 
>> nexthop.
>> This same question also occur in MVPN: RFC6515, which talks about MVPN6 over 
>> IPv4/IPv6, or MVPN over IPv6, but does imply loosely to use IPv4/IPv6 
>> without RD as nexthop (see below).
>>The purpose of this document is to make clear that whenever a PE
>>address occurs in an MCAST-VPN route (whether in the NLRI or in an
>>attribute), the IP address family of that address is determined by
>>the length of the address (a length of 4 octets for IPv4 addresses, a
>>length of 16 octets for IPv6 addresses), NOT by the AFI field of the
>>route.
>>  
>> My suggestion: implementation should interpret nexthop RD+IPv4 and nexthop 
>> IPv4 the same, and interpret nexthop RD+IPv6 and nexthop IPv6 the same.
>> The RFC5549/SRv6-VPN/RFC6515 can keep as current shape, while interoperate 
>> can meet between different implementations.
>> Need a new draft to clarify this and to give a guide on further FooService 
>> over FooNetwork ?
>>  
>> Thanks
>> Jingrong
>>  
>> From: Softwires [mailto:softwires-boun...@ietf.org 
>> ] On Behalf Of ian.far...@telekom.de 
>> 
>> Sent: Tuesday, June 25, 2019 11:12 PM
>> To: Zhuangshunwan > >; ianfar...@gmx.com 
>> 
>> Cc: softwi...@ietf.org ; bess@ietf.org 
>> 
>> 

Re: [bess] [Idr] [Softwires] Regarding the Next Hop Network Address coding for IPv4 VPN over IPv6 Core in RFC5549

[Robert Raszuk]

Hi Alex,

> My understanding is follow: RD is encoded in Next Hop field

That is subtle misinterpretation of the 4364 :)

The text says:

"When a PE router distributes a VPN-IPv4 route via BGP, it uses its  own
address as the "BGP next hop".  This address is encoded as a VPN-IPv4
address with an RD of 0."

That can be read as:

A) Next hop field has prepended zeros to match the NLRI format of 8 octet
RD + 4 octet IPv4 (for IPv4 case)

B) Next hop is of format RD:IPv4 where RD=0

My recollection and number of direct discussions with authors of
both2547/4364 & 4760 at that time leads me to believe we are dealing with
A. Of course anyone can see option B as valid, but at the end of the day it
is the same on the wire :)

So I am not sure what exactly the problem or the question we are trying to
answer is :)

Cheers,
R.






On Wed, Jun 26, 2019 at 3:22 PM Alexander Okonnikov <
alexander.okonni...@gmail.com> wrote:

> Hi,
>
> My understanding is follow: RD is encoded in Next Hop field, because
> authors of RFC 4364, while referring to RFC 2858, were trying to make it
> consistent with RFC 4760 (obsoletes RFC 2858). RFC 2858 says that Next Hop
> field should match AFI. On the other hand, RFC 4760 says that Next Hop
> Field should match combination of AFI/SAFI. Also, drafts of RFC 4364 and
> RFC 4760 were being developed practically at the same time period.
>
> 26 июня 2019 г., в 16:05, UTTARO, JAMES  написал(а):
>
> *+1*
>
> *From:* Idr  *On Behalf Of *Robert Raszuk
> *Sent:* Wednesday, June 26, 2019 7:53 AM
> *To:* Xiejingrong 
> *Cc:* i...@ietf.org; ian.far...@telekom.de; ianfar...@gmx.com;
> softwi...@ietf.org; bess@ietf.org
> *Subject:* Re: [Idr] [bess] [Softwires] Regarding the Next Hop Network
> Address coding for IPv4 VPN over IPv6 Core in RFC5549
>
> All,
>
> RD is a property of the NLRI not next hop. I am not sure where in this
> thread or some spec someone came to the conclusion that next hop field
> should contain an RD. RD is not useful there and should never be part of
> any next hop field.
>
> Remember RD role is to make prefix unique - that's it - no more no less.
> Next hop uniqness is given by architecture and there is no need to make it
> unique.
>
> In some cases when we need to carry IPv4 address in IPv6 next hop field
> (there was historically some assumption that next hop must be of the same
> AF as prefix) we prepend to it numerical zeros.
>
> Thx,
> R.
>
>
>
>
>
> On Wed, Jun 26, 2019 at 1:40 PM Xiejingrong 
> wrote:
>
> Hi folks,
>
> I guess this is an inconsistency due to past carelessness. Is there anyone
> can tell us the history of this inconsistency ?
> RFC4364(VPNv4 over IPv4 network) and RFC4659(VPNv6 over IPv4 or IPv6
> network) both require to use RD+IP(v4 or v6 respectively) as nexthop.
> RFC5549(VPNv4/IPv4 over IPv6 network) requires to use IPv6 without RD as
> nexthop.
> This same question also occur in MVPN: RFC6515, which talks about MVPN6
> over IPv4/IPv6, or MVPN over IPv6, but does imply loosely to use IPv4/IPv6
> without RD as nexthop (see below).
>The purpose of this document is to make clear that whenever a PE
>address occurs in an MCAST-VPN route (whether in the NLRI or in an
>attribute), the IP address family of that address is determined by
>the length of the address (a length of 4 octets for IPv4 addresses, a
>length of 16 octets for IPv6 addresses), NOT by the AFI field of the
>route.
>
> My suggestion: implementation should interpret nexthop RD+IPv4 and nexthop
> IPv4 the same, and interpret nexthop RD+IPv6 and nexthop IPv6 the same.
> The RFC5549/SRv6-VPN/RFC6515 can keep as current shape, while interoperate
> can meet between different implementations.
> Need a new draft to clarify this and to give a guide on further FooService
> over FooNetwork ?
>
> Thanks
> Jingrong
>
> *From:* Softwires [mailto:softwires-boun...@ietf.org] *On Behalf Of *
> ian.far...@telekom.de
> *Sent:* Tuesday, June 25, 2019 11:12 PM
> *To:* Zhuangshunwan ; ianfar...@gmx.com
> *Cc:* softwi...@ietf.org; bess@ietf.org
> *Subject:* Re: [Softwires] Regarding the Next Hop Network Address coding
> for IPv4 VPN over IPv6 Core in RFC5549
>
> Hi Shunwan,
>
> I’ve just re-checked RFC5539, and the referenced section 3 of RFC2545 and
> I can find nothing about using VPN-IPv6 for encoding the next-hop. Section
> 3 of RFC5539 is very clear that it’s a 16-byte GU IPv6 address or 32-bytes
> with a GU and LL address.
>
> Can you point me to the text that gives you the impression that VPN-IPv6
> is correct?
>
> Note – I see that there is reported Errata on RFC5549, (not verified)
> saying that the length should be 24 or 48 to include the RD. However, as
> mentioned above, the supporting text in multiple places in the RFC and its
> references support the use of an IPv6 address (or 2) with no RD at 16 or 32
> bytes, so this does seem to be the intention of the document as written.
> https://www.rfc-editor.org/errata_search.php?rfc=5549
> 

Re: [bess] [Idr] [Softwires] Regarding the Next Hop Network Address coding for IPv4 VPN over IPv6 Core in RFC5549

[Robert Raszuk]

And just to self complete the last sentence ...

The same leading zeros were also added to SAFI 128  in the next hop field
as to match the length of RD:IP prefix of the L3VPN NLRI. Original 2547 or
subsequent 4364 did not define explicitly that the size of the next hop
could be inferred from the nh length field - just took verbatim from 4760
that next hop is identified by AFI/SAFI of the NLRI itself .

But in general MP-BGP spec does not limit protocol designers. When you
define a new SAFI you are free to say that format of next hop will be
inferred from its length field or that next hop may not be present at all
as it does not make sense for a given SAFI (ref 5575) and that in turn will
be indicated by zero nh length

Many thx,
R.


On Wed, Jun 26, 2019 at 3:06 PM UTTARO, JAMES  wrote:

> *+1*
>
>
>
> *From:* Idr  *On Behalf Of * Robert Raszuk
> *Sent:* Wednesday, June 26, 2019 7:53 AM
> *To:* Xiejingrong 
> *Cc:* i...@ietf.org; ian.far...@telekom.de; ianfar...@gmx.com;
> softwi...@ietf.org; bess@ietf.org
> *Subject:* Re: [Idr] [bess] [Softwires] Regarding the Next Hop Network
> Address coding for IPv4 VPN over IPv6 Core in RFC5549
>
>
>
> All,
>
>
>
> RD is a property of the NLRI not next hop. I am not sure where in this
> thread or some spec someone came to the conclusion that next hop field
> should contain an RD. RD is not useful there and should never be part of
> any next hop field.
>
>
>
> Remember RD role is to make prefix unique - that's it - no more no less.
> Next hop uniqness is given by architecture and there is no need to make it
> unique.
>
>
>
> In some cases when we need to carry IPv4 address in IPv6 next hop field
> (there was historically some assumption that next hop must be of the same
> AF as prefix) we prepend to it numerical zeros.
>
>
>
> Thx,
>
> R.
>
>
>
>
>
>
>
>
>
>
>
> On Wed, Jun 26, 2019 at 1:40 PM Xiejingrong 
> wrote:
>
> Hi folks,
>
>
>
> I guess this is an inconsistency due to past carelessness. Is there anyone
> can tell us the history of this inconsistency ?
>
> RFC4364(VPNv4 over IPv4 network) and RFC4659(VPNv6 over IPv4 or IPv6
> network) both require to use RD+IP(v4 or v6 respectively) as nexthop.
>
> RFC5549(VPNv4/IPv4 over IPv6 network) requires to use IPv6 without RD as
> nexthop.
>
> This same question also occur in MVPN: RFC6515, which talks about MVPN6
> over IPv4/IPv6, or MVPN over IPv6, but does imply loosely to use IPv4/IPv6
> without RD as nexthop (see below).
>
>The purpose of this document is to make clear that whenever a PE
>
>address occurs in an MCAST-VPN route (whether in the NLRI or in an
>
>attribute), the IP address family of that address is determined by
>
>the length of the address (a length of 4 octets for IPv4 addresses, a
>
>length of 16 octets for IPv6 addresses), NOT by the AFI field of the
>
>route.
>
>
>
> My suggestion: implementation should interpret nexthop RD+IPv4 and nexthop
> IPv4 the same, and interpret nexthop RD+IPv6 and nexthop IPv6 the same.
>
> The RFC5549/SRv6-VPN/RFC6515 can keep as current shape, while interoperate
> can meet between different implementations.
>
> Need a new draft to clarify this and to give a guide on further FooService
> over FooNetwork ?
>
>
>
> Thanks
>
> Jingrong
>
>
>
> *From:* Softwires [mailto:softwires-boun...@ietf.org] *On Behalf Of *
> ian.far...@telekom.de
> *Sent:* Tuesday, June 25, 2019 11:12 PM
> *To:* Zhuangshunwan ; ianfar...@gmx.com
> *Cc:* softwi...@ietf.org; bess@ietf.org
> *Subject:* Re: [Softwires] Regarding the Next Hop Network Address coding
> for IPv4 VPN over IPv6 Core in RFC5549
>
>
>
> Hi Shunwan,
>
>
>
> I’ve just re-checked RFC5539, and the referenced section 3 of RFC2545 and
> I can find nothing about using VPN-IPv6 for encoding the next-hop. Section
> 3 of RFC5539 is very clear that it’s a 16-byte GU IPv6 address or 32-bytes
> with a GU and LL address.
>
>
>
> Can you point me to the text that gives you the impression that VPN-IPv6
> is correct?
>
>
>
> Note – I see that there is reported Errata on RFC5549, (not verified)
> saying that the length should be 24 or 48 to include the RD. However, as
> mentioned above, the supporting text in multiple places in the RFC and its
> references support the use of an IPv6 address (or 2) with no RD at 16 or 32
> bytes, so this does seem to be the intention of the document as written.
>
> https://www.rfc-editor.org/errata_search.php?rfc=5549
> 
>
>
>
> Thanks,
>
> Ian
>
>
>
> *From: *Softwires  on behalf of Zhuangshunwan
> 
> *Date: *Tuesday, 25. June 2019 at 13:18
> *To: *"ianfar...@gmx.com" 
> *Cc: *"softwi...@ietf.org" , "bess@ietf.org" <
> bess@ietf.org>
> *Subject: *Re: [Softwires] Regarding the Next Hop Network Address coding
> for IPv4 VPN over IPv6 Core in 

Re: [bess] [Idr] [Softwires] Regarding the Next Hop Network Address coding for IPv4 VPN over IPv6 Core in RFC5549

[Alexander Okonnikov]

Hi,

My understanding is follow: RD is encoded in Next Hop field, because authors of 
RFC 4364, while referring to RFC 2858, were trying to make it consistent with 
RFC 4760 (obsoletes RFC 2858). RFC 2858 says that Next Hop field should match 
AFI. On the other hand, RFC 4760 says that Next Hop Field should match 
combination of AFI/SAFI. Also, drafts of RFC 4364 and RFC 4760 were being 
developed practically at the same time period.

> 26 июня 2019 г., в 16:05, UTTARO, JAMES  написал(а):
> 
> +1
>  
> From: Idr mailto:idr-boun...@ietf.org>> On Behalf Of 
> Robert Raszuk
> Sent: Wednesday, June 26, 2019 7:53 AM
> To: Xiejingrong mailto:xiejingr...@huawei.com>>
> Cc: i...@ietf.org ; ian.far...@telekom.de 
> ; ianfar...@gmx.com ; 
> softwi...@ietf.org ; bess@ietf.org 
> 
> Subject: Re: [Idr] [bess] [Softwires] Regarding the Next Hop Network Address 
> coding for IPv4 VPN over IPv6 Core in RFC5549
>  
> All,
>  
> RD is a property of the NLRI not next hop. I am not sure where in this thread 
> or some spec someone came to the conclusion that next hop field should 
> contain an RD. RD is not useful there and should never be part of any next 
> hop field. 
>  
> Remember RD role is to make prefix unique - that's it - no more no less. Next 
> hop uniqness is given by architecture and there is no need to make it unique. 
>  
> In some cases when we need to carry IPv4 address in IPv6 next hop field 
> (there was historically some assumption that next hop must be of the same AF 
> as prefix) we prepend to it numerical zeros.
>  
> Thx,
> R.
>  
>  
>  
>  
>  
> On Wed, Jun 26, 2019 at 1:40 PM Xiejingrong  > wrote:
> Hi folks,
>  
> I guess this is an inconsistency due to past carelessness. Is there anyone 
> can tell us the history of this inconsistency ?
> RFC4364(VPNv4 over IPv4 network) and RFC4659(VPNv6 over IPv4 or IPv6 network) 
> both require to use RD+IP(v4 or v6 respectively) as nexthop.
> RFC5549(VPNv4/IPv4 over IPv6 network) requires to use IPv6 without RD as 
> nexthop.
> This same question also occur in MVPN: RFC6515, which talks about MVPN6 over 
> IPv4/IPv6, or MVPN over IPv6, but does imply loosely to use IPv4/IPv6 without 
> RD as nexthop (see below).
>The purpose of this document is to make clear that whenever a PE
>address occurs in an MCAST-VPN route (whether in the NLRI or in an
>attribute), the IP address family of that address is determined by
>the length of the address (a length of 4 octets for IPv4 addresses, a
>length of 16 octets for IPv6 addresses), NOT by the AFI field of the
>route.
>  
> My suggestion: implementation should interpret nexthop RD+IPv4 and nexthop 
> IPv4 the same, and interpret nexthop RD+IPv6 and nexthop IPv6 the same.
> The RFC5549/SRv6-VPN/RFC6515 can keep as current shape, while interoperate 
> can meet between different implementations.
> Need a new draft to clarify this and to give a guide on further FooService 
> over FooNetwork ?
>  
> Thanks
> Jingrong
>  
> From: Softwires [mailto:softwires-boun...@ietf.org 
> ] On Behalf Of ian.far...@telekom.de 
> 
> Sent: Tuesday, June 25, 2019 11:12 PM
> To: Zhuangshunwan  >; ianfar...@gmx.com 
> 
> Cc: softwi...@ietf.org ; bess@ietf.org 
> 
> Subject: Re: [Softwires] Regarding the Next Hop Network Address coding for 
> IPv4 VPN over IPv6 Core in RFC5549
>  
> Hi Shunwan,
>  
> I’ve just re-checked RFC5539, and the referenced section 3 of RFC2545 and I 
> can find nothing about using VPN-IPv6 for encoding the next-hop. Section 3 of 
> RFC5539 is very clear that it’s a 16-byte GU IPv6 address or 32-bytes with a 
> GU and LL address.
>  
> Can you point me to the text that gives you the impression that VPN-IPv6 is 
> correct?
>  
> Note – I see that there is reported Errata on RFC5549, (not verified) saying 
> that the length should be 24 or 48 to include the RD. However, as mentioned 
> above, the supporting text in multiple places in the RFC and its references 
> support the use of an IPv6 address (or 2) with no RD at 16 or 32 bytes, so 
> this does seem to be the intention of the document as written.
> https://www.rfc-editor.org/errata_search.php?rfc=5549 
> 
>  
> Thanks,
> Ian
>  
> From: Softwires  > on behalf of Zhuangshunwan 
> mailto:zhuangshun...@huawei.com>>
> Date: Tuesday, 25. June 2019 at 13:18
> To: "ianfar...@gmx.com "  >
> Cc: 

Re: [bess] [Idr] [Softwires] Regarding the Next Hop Network Address coding for IPv4 VPN over IPv6 Core in RFC5549

[UTTARO, JAMES]

+1

From: Idr  On Behalf Of Robert Raszuk
Sent: Wednesday, June 26, 2019 7:53 AM
To: Xiejingrong 
Cc: i...@ietf.org; ian.far...@telekom.de; ianfar...@gmx.com; 
softwi...@ietf.org; bess@ietf.org
Subject: Re: [Idr] [bess] [Softwires] Regarding the Next Hop Network Address 
coding for IPv4 VPN over IPv6 Core in RFC5549

All,

RD is a property of the NLRI not next hop. I am not sure where in this thread 
or some spec someone came to the conclusion that next hop field should contain 
an RD. RD is not useful there and should never be part of any next hop field.

Remember RD role is to make prefix unique - that's it - no more no less. Next 
hop uniqness is given by architecture and there is no need to make it unique.

In some cases when we need to carry IPv4 address in IPv6 next hop field (there 
was historically some assumption that next hop must be of the same AF as 
prefix) we prepend to it numerical zeros.

Thx,
R.





On Wed, Jun 26, 2019 at 1:40 PM Xiejingrong 
mailto:xiejingr...@huawei.com>> wrote:
Hi folks,

I guess this is an inconsistency due to past carelessness. Is there anyone can 
tell us the history of this inconsistency ?
RFC4364(VPNv4 over IPv4 network) and RFC4659(VPNv6 over IPv4 or IPv6 network) 
both require to use RD+IP(v4 or v6 respectively) as nexthop.
RFC5549(VPNv4/IPv4 over IPv6 network) requires to use IPv6 without RD as 
nexthop.
This same question also occur in MVPN: RFC6515, which talks about MVPN6 over 
IPv4/IPv6, or MVPN over IPv6, but does imply loosely to use IPv4/IPv6 without 
RD as nexthop (see below).
   The purpose of this document is to make clear that whenever a PE
   address occurs in an MCAST-VPN route (whether in the NLRI or in an
   attribute), the IP address family of that address is determined by
   the length of the address (a length of 4 octets for IPv4 addresses, a
   length of 16 octets for IPv6 addresses), NOT by the AFI field of the
   route.

My suggestion: implementation should interpret nexthop RD+IPv4 and nexthop IPv4 
the same, and interpret nexthop RD+IPv6 and nexthop IPv6 the same.
The RFC5549/SRv6-VPN/RFC6515 can keep as current shape, while interoperate can 
meet between different implementations.
Need a new draft to clarify this and to give a guide on further FooService over 
FooNetwork ?

Thanks
Jingrong

From: Softwires 
[mailto:softwires-boun...@ietf.org] On 
Behalf Of ian.far...@telekom.de
Sent: Tuesday, June 25, 2019 11:12 PM
To: Zhuangshunwan mailto:zhuangshun...@huawei.com>>; 
ianfar...@gmx.com
Cc: softwi...@ietf.org; 
bess@ietf.org
Subject: Re: [Softwires] Regarding the Next Hop Network Address coding for IPv4 
VPN over IPv6 Core in RFC5549

Hi Shunwan,

I’ve just re-checked RFC5539, and the referenced section 3 of RFC2545 and I can 
find nothing about using VPN-IPv6 for encoding the next-hop. Section 3 of 
RFC5539 is very clear that it’s a 16-byte GU IPv6 address or 32-bytes with a GU 
and LL address.

Can you point me to the text that gives you the impression that VPN-IPv6 is 
correct?

Note – I see that there is reported Errata on RFC5549, (not verified) saying 
that the length should be 24 or 48 to include the RD. However, as mentioned 
above, the supporting text in multiple places in the RFC and its references 
support the use of an IPv6 address (or 2) with no RD at 16 or 32 bytes, so this 
does seem to be the intention of the document as written.
https://www.rfc-editor.org/errata_search.php?rfc=5549

Thanks,
Ian

From: Softwires mailto:softwires-boun...@ietf.org>> 
on behalf of Zhuangshunwan 
mailto:zhuangshun...@huawei.com>>
Date: Tuesday, 25. June 2019 at 13:18
To: "ianfar...@gmx.com" 
mailto:ianfar...@gmx.com>>
Cc: "softwi...@ietf.org" 
mailto:softwi...@ietf.org>>, 
"bess@ietf.org" mailto:bess@ietf.org>>
Subject: Re: [Softwires] Regarding the Next Hop Network Address coding for IPv4 
VPN over IPv6 Core in RFC5549

Hi Ian,

Thanks for your response!

The opinion I have collected is:
Per RFC4634, the IPv4-VPN routes shall carry the V4 Next-hop, beginning with an 
8-octet RD and ending with a 4-octet IPv4 address.
Per RFC4659, the IPv6-VPN routes shall carry the V6 Next-hop, beginning with an 
8-octet RD and ending with a 16-octet IPv6 address.
When we start to implement the IPv4 VPN over IPv6 Core,  it is a natural way to 
encode the IPv4-VPN routes with VPN-IPv6 next-hop (i.e. beginning with an 
8-octet RD and ending with a 16-octet IPv6 address) .

I believe this is not just a minority opinion, and some of the current 
implementations are also doing this way.

I hope that the 

Re: [bess] [Softwires] Regarding the Next Hop Network Address coding for IPv4 VPN over IPv6 Core in RFC5549

[Robert Raszuk]

All,

RD is a property of the NLRI not next hop. I am not sure where in this
thread or some spec someone came to the conclusion that next hop field
should contain an RD. RD is not useful there and should never be part of
any next hop field.

Remember RD role is to make prefix unique - that's it - no more no less.
Next hop uniqness is given by architecture and there is no need to make it
unique.

In some cases when we need to carry IPv4 address in IPv6 next hop field
(there was historically some assumption that next hop must be of the same
AF as prefix) we prepend to it numerical zeros.

Thx,
R.





On Wed, Jun 26, 2019 at 1:40 PM Xiejingrong  wrote:

> Hi folks,
>
>
>
> I guess this is an inconsistency due to past carelessness. Is there anyone
> can tell us the history of this inconsistency ?
>
> RFC4364(VPNv4 over IPv4 network) and RFC4659(VPNv6 over IPv4 or IPv6
> network) both require to use RD+IP(v4 or v6 respectively) as nexthop.
>
> RFC5549(VPNv4/IPv4 over IPv6 network) requires to use IPv6 without RD as
> nexthop.
>
> This same question also occur in MVPN: RFC6515, which talks about MVPN6
> over IPv4/IPv6, or MVPN over IPv6, but does imply loosely to use IPv4/IPv6
> without RD as nexthop (see below).
>
>The purpose of this document is to make clear that whenever a PE
>
>address occurs in an MCAST-VPN route (whether in the NLRI or in an
>
>attribute), the IP address family of that address is determined by
>
>the length of the address (a length of 4 octets for IPv4 addresses, a
>
>length of 16 octets for IPv6 addresses), NOT by the AFI field of the
>
>route.
>
>
>
> My suggestion: implementation should interpret nexthop RD+IPv4 and nexthop
> IPv4 the same, and interpret nexthop RD+IPv6 and nexthop IPv6 the same.
>
> The RFC5549/SRv6-VPN/RFC6515 can keep as current shape, while interoperate
> can meet between different implementations.
>
> Need a new draft to clarify this and to give a guide on further FooService
> over FooNetwork ?
>
>
>
> Thanks
>
> Jingrong
>
>
>
> *From:* Softwires [mailto:softwires-boun...@ietf.org] *On Behalf Of *
> ian.far...@telekom.de
> *Sent:* Tuesday, June 25, 2019 11:12 PM
> *To:* Zhuangshunwan ; ianfar...@gmx.com
> *Cc:* softwi...@ietf.org; bess@ietf.org
> *Subject:* Re: [Softwires] Regarding the Next Hop Network Address coding
> for IPv4 VPN over IPv6 Core in RFC5549
>
>
>
> Hi Shunwan,
>
>
>
> I’ve just re-checked RFC5539, and the referenced section 3 of RFC2545 and
> I can find nothing about using VPN-IPv6 for encoding the next-hop. Section
> 3 of RFC5539 is very clear that it’s a 16-byte GU IPv6 address or 32-bytes
> with a GU and LL address.
>
>
>
> Can you point me to the text that gives you the impression that VPN-IPv6
> is correct?
>
>
>
> Note – I see that there is reported Errata on RFC5549, (not verified)
> saying that the length should be 24 or 48 to include the RD. However, as
> mentioned above, the supporting text in multiple places in the RFC and its
> references support the use of an IPv6 address (or 2) with no RD at 16 or 32
> bytes, so this does seem to be the intention of the document as written.
>
> https://www.rfc-editor.org/errata_search.php?rfc=5549
>
>
>
> Thanks,
>
> Ian
>
>
>
> *From: *Softwires  on behalf of Zhuangshunwan
> 
> *Date: *Tuesday, 25. June 2019 at 13:18
> *To: *"ianfar...@gmx.com" 
> *Cc: *"softwi...@ietf.org" , "bess@ietf.org" <
> bess@ietf.org>
> *Subject: *Re: [Softwires] Regarding the Next Hop Network Address coding
> for IPv4 VPN over IPv6 Core in RFC5549
>
>
>
> Hi Ian,
>
>
>
> Thanks for your response!
>
>
>
> The opinion I have collected is:
>
> Per RFC4634, the IPv4-VPN routes shall carry the V4 Next-hop, beginning
> with an 8-octet RD and ending with a 4-octet IPv4 address.
>
> Per RFC4659, the IPv6-VPN routes shall carry the V6 Next-hop, beginning
> with an 8-octet RD and ending with a 16-octet IPv6 address.
>
> When we start to implement the IPv4 VPN over IPv6 Core,  it is a natural
> way to encode the IPv4-VPN routes with VPN-IPv6 next-hop (i.e. beginning
> with an 8-octet RD and ending with a 16-octet IPv6 address) .
>
>
>
> I believe this is not just a minority opinion, and some of the current
> implementations are also doing this way.
>
>
>
> I hope that the WGs can give a consistent opinion on this issue and avoid
> interoperability problem in the future.
>
>
>
> Thanks,
>
> Shunwan
>
>
>
> *From:* ianfar...@gmx.com [mailto:ianfar...@gmx.com ]
> *Sent:* Monday, June 24, 2019 8:08 PM
> *To:* Zhuangshunwan 
> *Cc:* bess@ietf.org; softwi...@ietf.org
> *Subject:* Re: [Softwires] Regarding the Next Hop Network Address coding
> for IPv4 VPN over IPv6 Core in RFC5549
>
>
>
> Hi,
>
>
>
> My reading of Section 3 of RFC5549 is that the v6 next-hop is encoded as
> an IPv6 address:
>
>
>
>The BGP speaker receiving the advertisement MUST use the Length of
>
>Next Hop Address field to determine which network-layer protocol the
>
>next hop address belongs to.  When the Length of Next Hop 

Re: [bess] [Softwires] Regarding the Next Hop Network Address coding for IPv4 VPN over IPv6 Core in RFC5549

[Xiejingrong]

Hi folks,

I guess this is an inconsistency due to past carelessness. Is there anyone can 
tell us the history of this inconsistency ?
RFC4364(VPNv4 over IPv4 network) and RFC4659(VPNv6 over IPv4 or IPv6 network) 
both require to use RD+IP(v4 or v6 respectively) as nexthop.
RFC5549(VPNv4/IPv4 over IPv6 network) requires to use IPv6 without RD as 
nexthop.
This same question also occur in MVPN: RFC6515, which talks about MVPN6 over 
IPv4/IPv6, or MVPN over IPv6, but does imply loosely to use IPv4/IPv6 without 
RD as nexthop (see below).
   The purpose of this document is to make clear that whenever a PE
   address occurs in an MCAST-VPN route (whether in the NLRI or in an
   attribute), the IP address family of that address is determined by
   the length of the address (a length of 4 octets for IPv4 addresses, a
   length of 16 octets for IPv6 addresses), NOT by the AFI field of the
   route.

My suggestion: implementation should interpret nexthop RD+IPv4 and nexthop IPv4 
the same, and interpret nexthop RD+IPv6 and nexthop IPv6 the same.
The RFC5549/SRv6-VPN/RFC6515 can keep as current shape, while interoperate can 
meet between different implementations.
Need a new draft to clarify this and to give a guide on further FooService over 
FooNetwork ?

Thanks
Jingrong

From: Softwires [mailto:softwires-boun...@ietf.org] On Behalf Of 
ian.far...@telekom.de
Sent: Tuesday, June 25, 2019 11:12 PM
To: Zhuangshunwan ; ianfar...@gmx.com
Cc: softwi...@ietf.org; bess@ietf.org
Subject: Re: [Softwires] Regarding the Next Hop Network Address coding for IPv4 
VPN over IPv6 Core in RFC5549

Hi Shunwan,

I’ve just re-checked RFC5539, and the referenced section 3 of RFC2545 and I can 
find nothing about using VPN-IPv6 for encoding the next-hop. Section 3 of 
RFC5539 is very clear that it’s a 16-byte GU IPv6 address or 32-bytes with a GU 
and LL address.

Can you point me to the text that gives you the impression that VPN-IPv6 is 
correct?

Note – I see that there is reported Errata on RFC5549, (not verified) saying 
that the length should be 24 or 48 to include the RD. However, as mentioned 
above, the supporting text in multiple places in the RFC and its references 
support the use of an IPv6 address (or 2) with no RD at 16 or 32 bytes, so this 
does seem to be the intention of the document as written.
https://www.rfc-editor.org/errata_search.php?rfc=5549

Thanks,
Ian

From: Softwires mailto:softwires-boun...@ietf.org>> 
on behalf of Zhuangshunwan 
mailto:zhuangshun...@huawei.com>>
Date: Tuesday, 25. June 2019 at 13:18
To: "ianfar...@gmx.com" 
mailto:ianfar...@gmx.com>>
Cc: "softwi...@ietf.org" 
mailto:softwi...@ietf.org>>, 
"bess@ietf.org" mailto:bess@ietf.org>>
Subject: Re: [Softwires] Regarding the Next Hop Network Address coding for IPv4 
VPN over IPv6 Core in RFC5549

Hi Ian,

Thanks for your response!

The opinion I have collected is:
Per RFC4634, the IPv4-VPN routes shall carry the V4 Next-hop, beginning with an 
8-octet RD and ending with a 4-octet IPv4 address.
Per RFC4659, the IPv6-VPN routes shall carry the V6 Next-hop, beginning with an 
8-octet RD and ending with a 16-octet IPv6 address.
When we start to implement the IPv4 VPN over IPv6 Core,  it is a natural way to 
encode the IPv4-VPN routes with VPN-IPv6 next-hop (i.e. beginning with an 
8-octet RD and ending with a 16-octet IPv6 address) .

I believe this is not just a minority opinion, and some of the current 
implementations are also doing this way.

I hope that the WGs can give a consistent opinion on this issue and avoid 
interoperability problem in the future.

Thanks,
Shunwan

From: ianfar...@gmx.com [mailto:ianfar...@gmx.com]
Sent: Monday, June 24, 2019 8:08 PM
To: Zhuangshunwan mailto:zhuangshun...@huawei.com>>
Cc: bess@ietf.org; 
softwi...@ietf.org
Subject: Re: [Softwires] Regarding the Next Hop Network Address coding for IPv4 
VPN over IPv6 Core in RFC5549

Hi,

My reading of Section 3 of RFC5549 is that the v6 next-hop is encoded as an 
IPv6 address:

   The BGP speaker receiving the advertisement MUST use the Length of
   Next Hop Address field to determine which network-layer protocol the
   next hop address belongs to.  When the Length of Next Hop Address
   field is equal to 16 or 32, the next hop address is of type IPv6.

It’s also worth noting that RFC4659 Section 2 states:

A VPN-IPv6 address is a 24-octet quantity, beginning with an 8-octet
   "Route Distinguisher" (RD) and ending with a 16-octet IPv6 address.

So, not 16 or 32 bytes.

Thanks,
Ian



On 22. Jun 2019, at 09:59, Zhuangshunwan 
mailto:zhuangshun...@huawei.com>> wrote:

Dear authors and WGs,

RFC5549 Section 6.2 says:

. 6.2.  IPv4 VPN over IPv6 Core
.
.The extensions defined in this document may be used for support of
.IPV4 VPNs over an IPv6 backbone.  In this application, PE routers
.would advertise VPN-IPv4 NLRI