Re: [Idr] draft-decraene-idr-reserved-extended-communities-00

[Eric Rosen <[e-mail]>]

> Reserving 2^48 = 2.8 10^14 = two hundreds thousand billions communities
> while a single is required, I call this wasting resources.

The resource being wasted is the 2^48 potential values of the low order six
bytes of the extended community??  I.e., there are 2^48 values that could
have been used for codepoints but are instead going wasted?

How many codepoint values do you expect IANA to assign from this registry?
Even if they assign, say, a billion, the resource utilization will still be
pretty close to zero.

> We ran out of class B, AS number, IP addresses, optional parameter
> length... How can you be certain that we will never run out of extended
> types?

I don't think the proposed registry is a very good hedge against running out
of extended types, as it essentially creates an extended community that
consists of eight bytes of type field and zero bytes of value field.  If we
use up all the two-byte extended type values, we will probably still want
some value field bytes.

> if _you_ believe these are evil, you will be able to remove or not
> interpret them.

It's hard to imagine that all 2^48 codepoints will be evil.

> A registry for reserved/well known/std action community do exist. Do you
> have a concern with it?

Yes, I don't think it makes any sense to have a registry for communities
that "have global significance and their operations shall be implemented in
any community-attribute-aware BGP speaker"; obviously one can't allocate a
new codepoint from that registry without throwing all existing
implementations out of compliance.