Re: [Idr] Review of draft-ietf-large-community-06.txt

[Geoff Huston <[e-mail]>]

>> 4.  Canonical Representation
>> 
>> I am confused here - this section used an example with TWO canonical
>> representations:
>> 
>>   "For example: 64496:4294967295:2, 64496:0:0, or (64496, 111, 222)."
>> 
>> 
>> Conventionally, it's better to use a single canonical representation, so the
>> authors should pick either a colon-delimited list, or a bracketed comma+space
>> separated object.

> On 4 Nov. 2016, at 3:05 pm, Jakob Heitz (jheitz) <[e-mail]> wrote:
> 
> To explain this one, it was originally "Textual Representation"
> and it was with colons only. Then we discovered that Bird uses
> commas as a separator. Since that does not degrade the utility,
> we allowed it. The real point is that it has to be exactly
> 3 positive decimal integers. If some implementations only offered hexadecimal
> or used 6 int16's then it would become very difficult for ISPs
> to communicate community settings to customers.
> I can change it to a single representation and detail the allowed
> deviations from it.
> 

if you make a canonical a SHOULD not a MUST then you can permit variation
without breaking the standard.

So what you are saying is that the canonical representation of a single Large Community value
is three unsigned decimal integer values, separated by a ‘:’ (colon) character, representing 
the value as a triplet of unsigned 32-bit integer values. Implementations SHOULD accept this
representation as a valid form of representation of the value of a Large Community.