Re: draft-dong-6man-enhanced-vpn-vtn-id-01

["Joel M. Halpern" <[e-mail]>]

If you coupled this with SR, you would get most of what you want.
And for those cases where you needed more, you could use a destination 
option.

Otherwise, you are going to have some other hard to guess dependencies 
to make this work meaningfully.

Yours,
Joel

On 7/31/2020 12:32 PM, Dongjie (Jimmy) wrote:
> Hi Joel,
> 
> Thanks for your comment, I missed this before the meeting.
> 
> We understand forwarding loops must be avoided. As mentioned in the draft and my presentation, the next hop is determined using the destination IP field, and the VTN-ID is used to determine the set of network resources associated with the VTN for packet processing and forwarding to the determined next hop.
> 
> Hope this helps.
> 
> Best regards,
> Jie
> 
>> -----Original Message-----
>> From: Joel Halpern Direct [mailto:[e-mail]]
>> Sent: Friday, July 31, 2020 7:08 PM
>> To: Dongjie (Jimmy) <[e-mail]>; [e-mail]
>> Subject: Re: draft-dong-6man-enhanced-vpn-vtn-id-01
>>
>> Looking at the draft, and reading your note, you seem to be asking for a
>> hop-by-hop option header which is to be modify the forwarding selection in
>> some unspecified fashion.
>>
>> This kind of open-ended modification of core 6man IPv6 behavior seems a bad
>> idea.
>> Having a modification to the forwarding behavior that may not be noticed or
>> acted on by all routers in the path seems a recipe for forwarding loops.
>>
>> And it is not at all clear that there is any need for this given MPLS, SRH, CRH.
>>
>> Yours,
>> Joel
>>
>> On 7/31/2020 4:47 AM, Dongjie (Jimmy) wrote:
>>> Hi Joel,
>>>
>>> As explained in my previous mail, the role of DSCP and VTN-ID are different.
>> VTN-ID can be used as a in packet identifier of the VTN, and it can be used in a
>> hierarchical manner with DSCP and other fields for packet forwarding. Thus it
>> is not to extend or replace DSCP.
>>>
>>> Best regards,
>>> Jie
>>>
>>>> -----Original Message-----
>>>> From: Joel M. Halpern [mailto:[e-mail]]
>>>> Sent: Wednesday, July 29, 2020 9:40 PM
>>>> To: Dongjie (Jimmy) <[e-mail]>; [e-mail]
>>>> Subject: Re: draft-dong-6man-enhanced-vpn-vtn-id-01
>>>>
>>>> It is unclear to me whether you are asserting that DSCP is
>>>> insufficiently granular to represent the desired treatment, or
>>>> whether youa re asking for an in-packet identifier that does not affect
>> packet queueing or forwarding?
>>>>
>>>> Yours,
>>>> Joel
>>>>
>>>> On 7/29/2020 3:43 AM, Dongjie (Jimmy) wrote:
>>>>> Hi Ron,
>>>>>
>>>>> Thanks for your review and comment.
>>>>>
>>>>> Your interpretation is in the right direction, while the
>>>>> relationship between VTN-ID and DSCP could be considered as in a
>>>>> hierarchical manner, and each is for different purpose. VTN-ID is
>>>>> used to consistently identify a virtual network with a group of
>>>>> network resources allocated from the network, there is no priority
>>>>> difference between VTNs. DSCP is used to provide class (priority)
>>>>> based traffic differentiation, which can be used within VTN.
>>>>>
>>>>> Hope this helps.
>>>>>
>>>>> Best regards,
>>>>>
>>>>> Jie
>>>>>
>>>>> *From:*ipv6 [mailto:[e-mail]] *On Behalf Of *Ron Bonica
>>>>> *Sent:* Wednesday, July 29, 2020 1:45 AM
>>>>> *To:* [e-mail]
>>>>> *Subject:* draft-dong-6man-enhanced-vpn-vtn-id-01
>>>>>
>>>>> Co-authors,
>>>>>
>>>>> In Section 4.2, you say:
>>>>>
>>>>> "There can be different implementations of reserving local network
>>>>>
>>>>>       resources to the VTNs.  On each interface, the resources
>>>>> allocated to
>>>>>
>>>>>       a particular VTN can be seen as a virtual sub-interface with
>>>>>
>>>>>       dedicated bandwidth and other associated resources.  In packet
>>>>>
>>>>>       forwarding, the IPv6 destination address of the received packet
>>>>> is
>>>>>
>>>>>       used to identify the next-hop and the outgoing interface, and
>>>>> the VTN
>>>>>
>>>>>       ID is used to further identify the virtual sub-interface which
>>>>> is
>>>>>
>>>>>       associated with the VTN on the outgoing interface."
>>>>>
>>>>> I interpret this as meaning:
>>>>>
>>>>> -The IPv6 destination address is solely responsible for identifying
>>>>> the IP next hop
>>>>>
>>>>> -The VTNI, along with the DSCP bits, determine how the packet is
>>>>> forwarded to the next-hop
>>>>>
>>>>> So, I can think of the VTNI as "more DSCP bits".
>>>>>
>>>>> Do I have that right?
>>>>>
>>>>>
>>>>                  Ron
>>>>>
>>>>> Juniper Business Use Only
>>>>>
>>>>>
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