Re: [v6ops] Comments to draft-mlevy-v6ops-auto-v6-allocation-per-asn

[Dino Farinacci <[e-mail]>]

On Feb 19, 2013, at 5:09 PM, Owen DeLong <[e-mail]> wrote:

>>> I think permanently assigned addresses related to VINS are, in general, a bad idea. I don't see any advantage to tying the semantics of the two systems to each other. If anything, the development of LISP is the result of failing to separate the semantics of end-point addressing from the semantics of topological location. Combining the semantics of end-point addressing and VINs seems even more far-fetched to me.
>> 
>> An EID is opaque and not used by the protocol stack just by humans if they choose to look at them. 
>> 
> 
> One of us is misunderstanding the other. My point is that using IPv6 address space to number things that are not IPv6 hosts is, IMHO, a bad idea.

The automobiles are IPv6 hosts. 

> 
>>>> (3) What if these auto manufactures don't want to allocate ASN numbers because they will never have any intent to run BGP either in the cars, POPs, data centers?
>>>> 
>>> 
>>> I don't see anything in this draft that would preclude them from using a different source of addressing.
>>> 
>>> I confess, to some extent, I wonder if this is a solution in search of a problem.
>> 
>> I know there are customers that want to reduce the number of total databases they have to manage at all layers of the stack.
>> 
> 
> All well and good, but I do not support turning IPv6 addresses into the primary key for everything in world anyone wants to identify in any namespace. If that's not what your sentence above means, then I'm afraid I misunderstand your meaning.

It is none of your business how sites use their addresses. That is the whole point of ID/Locator separation. 

The EID is opaque to the network but may have meaning to the sites who communicate with each other within that EID-prefix. 

> Again, I do not support the idea of using IPv6 numbers as a mechanism for identifying anything that isn't an IPv6 host and I do not support tying semantics other than the host end-system identifier for packet delivery to IPv6 addresses. I think that past experience has demonstrated that both of these practices create more problems than they solve.

See above. Tell me if you still disagree and if so we will have to disagree. This is where IPv6 could be useful. What does IPv6 have that IPv4 doesn't? Really only longer addresses. 

> 
>>>>> If any route is announced from this allocation, any prefixes more
>>>>> specific than the allocated /48 must not be propagated in to the
>>>>> global IPv6 routing table.  This is to prevent the IPv6 routing table
>>>> 
>>>> This is fine authors, but if you are multi-home, it will require each system at the site to possess multiple addresses one from each attached ASN if they do not have their own prefix but get it out of their provider.
>>>> 
>>>> If you say that this prefix will never be associated with a provider's attachment point, then I'm okay with that and agree.
>>>> 
>>> 
>>> Either I misunderstand what you are saying, or, you have erred. I'm not sure which.
>>> 
>>> If a site uses a /64 from within this /48 to attach to each upstream, the more specific does not need to propagate beyond the immediate upstream router, so it still wouldn't be announced into the global routing table.
>> 
>> There is still PI flat routing on the scale of number of sites that use this prefix. That is the point, there is no attempt to improve the route table scaling problem. I'm not saying this draft should, just speaking generally.
> 
> I think that concern is entirely orthogonal to this draft. My point is that for every PI
> prefix that gets advertised from this space, it should represent a PI prefix from RIR
> space that does not get advertised, so it is a net equivalence in terms of the
> routing table. Thus, I would anticipate that this draft has no impact on the routing
> table.

Okay fine. 

> OTOH, the whole way we do IDR is broken and we should have fixed it as part
> of the IPv6 development process. Unfortunately, we (IETF) chose to punt on that and
> go down all kinds of other less important roads. However, this issue is really
> not part of the discussion of this draft.

If locator/ID separation is used then this is helped and you make multi-homing  easier at the same time as making address management in every host. 

Look how complicated the home networking proposals are?

> 
>>>>> from becoming too large.  Therefore, a site which uses this
>>>>> allocation MUST NOT advertise a more specific than the allocated /48
>>>>> routing prefix.  All native IPv6 network operators MUST filter out
>>>>> 
>>>>> 
>>>>> 
>>>>> Levy & Pounsett           Expires July 28, 2013                 [Page 3]
>>>>> Internet-Draft  Auto allocation mechanism for IPv6 blocks   January 2013
>>>>> 
>>>>> 
>>>>> and discard any routing prefix advertisements longer than /48 from
>>>>> within this /16 allocation.
>>>> 
>>>> Can you explicitly state then that this prefix for use as a PROVIDER INDEPENDENT prefix. Thanks.
>>>> 
>>> 
>>> I think that is inherent in the definition of the prefix. Can you clarify why you think this
>>> statement is necessary?
>> 
>> I want it explicit so there is no layers of ownership of the prefix.
>> 
> 
> I'm not sure how stating that this prefix is PROVIDER INDEPENDENT conveys any ownership or lack thereof.

Never mind - bit worth arguing the point. 

> 
>>>>> ASNs are normally expressed as human-readable decimal numbers; yet
>>>>> for this allocation the number should be converted into a hexadecimal
>>>>> notation.  All IPv6 addresses are written in hexadecimal.  (NNNN
>>>>> represents the /16 allocation by IANA)
>>>>> 
>>>>>    +----------------+--------------------+---------------------+
>>>>>    | ASN in decemal | ASN in hexadecimal |     Sample IP block |
>>>>>    +----------------+--------------------+---------------------+
>>>>>    |            AS1 |                  1 | NNNN:0000:0001::/48 |
>>>>>    |         AS6939 |               1B1B | NNNN:0000:1B1B::/48 |
>>>>>    |        AS29001 |               7149 | NNNN:0000:0001::/48 |
>>>>>    |       AS393220 |              60004 | NNNN:0006:0004::/48 |
>>>>>    +----------------+--------------------+---------------------+
>>>> 
>>>> What we had found in the old days of NSAP deployment (OSI) that encoding IPv4 addresses in BCD format in a hexadecimal longer address was extremely useful for management. And as we have seen for IPv6, even embedding IPv4 dotted decimal format was extremely useful.
>>>> 
>>>> Rather than having to build tools and make vendors do UI work, can we have some form of BCD format for AS number. I know this will be difficult for a 32-bit number but we could make it work for the ASNs that are <= 65535. Just a thought. But even 10 million ASNS would only take up to 8 nibbles. And since we won't and can't aggregate ASNs there is no point in making the encoding a power-of-2 value.
>>> 
>>> I would oppose doing this. If we are going to do this (and I'm not entirely convinced that we should, but also not opposed), we should support the full ASN space and doing so as a bit field is fine. I don't think any UI work is required. Tools to convert 32-bit numbers from decimal to hex are already widely available and the process is well understood. It's not like anyone will have to do this conversion on a daily basis.
>>> 
>>> perl -e 'printf "%08x\n", <as_number_in_decimal>' will solve the problem, for example.
>> 
>> Multiply by 1000 products coming out over different delivery times. Don't underestimate the slowness of vendors.
>> 
> 
> I'm not sure what you mean by this. Why would products coming out receive AS Numbers? I think you are pursuing a use case that is not intended under my interpretation of this draft and taking it to extremes that are beyond my comprehension.

I mean each product would have to build a hex to decimal conversion capability in their UI. 

> 
>>>>> 5.  ASN allocation
>>>>> 
>>>>> ASNs are allocated by RIRs and this RFC does not handle that arena.
>>>>> 
>>>>> ASNs defined as private ASNs MUST NOT use this scheme.  The special
>>>>> 16-bit ASN 23456 MUST NOT use this scheme.
>>>> 
>>>> I would let users do this with private ASes if they want to. Set a local/global bit in your encoding so they can use it. If you don't they will steal ASN numbers which they should not do but will.
>>> 
>>> What local/global bit?
>> 
>> Add one is the suggestion.
>> 
> 
> I expected that's where you were going. I think 16 bits is already a rather short prefix for this use case. I don't believe that there is a sufficient use case for a local/global bit. If you do, you need to make a better case for it than the above.

Well explicitly encoding that the intent of the address is local is a good thing IMO. 

> 
> I would propose modifying section 5 of the draft to state, instead of "ASNs MUST NOT use..." that "ASNs MUST NOT advertise..." and that any prefixes within the prefix allocated for this purpose must be considered "LOCAL addresses and given similar semantics to RFC-1918".

Sounds good. 

> 
> I would not give the the semantics of ULA because of the likelihood of overlap.
> 
>>>>> This mechanism is not expected to have any impact to the global
>>>>> Internet routing table since existing policies in the RIR system
>>>>> already readily provide for the allocation of provider-independent
>>>>> IPv6 prefixes.  Additionally, AS number holders are likely to be
>>>>> multihomed entities which were going to be independently routed in
>>>>> any case.  Service Providers are, as always, not obligated to route
>>>>> these IPv6 assignments and/or may establish conditions of service
>>>>> which offset any additional routing cost.
>>>> 
>>>> I would say it would have the same impact as PI prefixes do today.
>>>> 
>>> 
>>> Which means that this has no impact because it doesn't change the impact vs. the current PI impact.
>> 
>> You miss the point. The problem needs to be solved. Saying this draft doesn't worsen it is not panacea.
>> 
> 
> You miss the point. This draft is not intending to solve that problem and makes no claim in that respect.

I understand that and I'm not saying the spec should fix it. I was replying to your comment only. 

> 
> I agree the problem needs to be solved. However, Solving the problem isn't even within the purview of the v6ops working group. Raising it as an

I realize that.  But not let's process get in the way of having an open dialogue. 

> issue in the discussion of this draft is only relevant to the extent that this draft makes the problem worse or prevents any proposed solution to the problem from being effective. Since neither of those applies, there are no routing table considerations applicable to this draft IMHO.
> 
> Owen

Fine. Thanks for listening. 

Dino