Re: [MBONED] ipv4 multicast address ranges, actual usage.

["Holland, Jake" <[e-mail]>]

Hi Dave,

I think the framing of "actual usage" isn't quite the best way to look
at it.

Much like ECN and IPv6, there were some hurdles and it took longer than
anyone hoped, but it's not dead yet, the reasons to use it are still
with us, and there has been recent movement that's giving some cause
for hope that the next few years might see a much expanded deployment.
(Any day now...)

With that said:

232/8 is extremely important, from my point of view.  I'd also be
slightly reluctant to give up 233 or 239, though I care much less
about them than 232.

The rest of the space I have no attachment to.

Reasons:

ASM for interdomain is in process of getting deprecated:
https://tools.ietf.org/html/draft-ietf-mboned-deprecate-interdomain-asm-03

But SSM is still the way of the future, with any luck, and the 232/8
allocation is critical to its usability.  (The flexibility on 233 and
239 that makes them candidates for extra SSM space is also the biggest
part of what I like about them.)

My deployment is still pretty limited today, but a couple of my recent
drafts are trying to get it over a few final hurdles:
https://tools.ietf.org/html/draft-ietf-mboned-driad-amt-discovery-10
https://tools.ietf.org/html/draft-jholland-mboned-dorms-00
(plus a couple of augmentations to dorms that try to enable a safe
MulticastReceiver W3C API.)

Once these hurdles are solved, it's my sincere hope to start rolling out
interdomain usage of 232/8 at as big a scale as I can muster.  (I have a
few trickles available today, but "actually used" for interdomain traffic
is still a bit of a stretch.)

Provided that SSM is left alone, I have no objections that are
specifically about reassigning unused multicast address space.  (For
this venue, I'll leave aside any questions about the overall wisdom of
the project... :) )

Best,
Jake


On 2019-12-18, 13:02, "Dave Taht" <[e-mail]> wrote:

On Wed, Dec 18, 2019 at 12:49 PM Leonard Giuliano <[e-mail]> wrote:
>
> Dave,
>
> Take a look at RFC6308 and RFC 5771 for an overview of multicast
> addressing.  But to summarize, 232/8 is reserved for SSM (RFC4607).
> 233/8 is reserved for GLOP (RFC3180).  234/8 is reserved for
> Unicast-Prefix-Based Allocation (RFC6034).  239/8 is reserved for admin
> scoped allocation (RFC2365).

I had already reviewed those pretty thoroughly in writing the drafty draft.

The question was:

"to what extent are the various allocations in the 232/8 to 238/8
range actually used today, and for
what?"

The "for what" portion of the question was: what applications today
actually use GLOP? or RFC6038? or SSM?

What mailing list or list might have some answers to the actual usage
of these ranges?

As best as I can tell actual multicast usage of ipv4 is down to the
dozens of applications (all with allocated ip address in 224 or 239 -
with mdns topping the list.
>
> Hope this helps,
> Lenny
>
> On Wed, 18 Dec 2019, Dave Taht wrote:
>
> | As a few people know I've been working (quixotically) in my spare time
> | towards making more of the IPv4 address space generally usable. We've
> | landed patches for 0/8 in linux, and 240/4 had already been mostly
> | made working a decade back.
> |
> | Now we come against a harder problem, in that 1) - a vast swath of
> | multicast address space was never allocated for anything by iana
> | (225/8-231/8) and 2) 232/8-238/8 appears severely underutilized. Only
> | portions of 224/8 and 239/8 seem to have any usage at all.
> |
> | We've successfully made that first formerly multicast range pretty
> | generally usable in a string of patches on our github for various oses
> | and routing daemons. https://github.com/dtaht/unicast-extensions - and
> | for a drafty draft of a draft internet draft, see:
> | https://github.com/dtaht/unicast-extensions/blob/master/rfcs/draft-gilmore-taht-v4uniext.txt
> |
> | My question today, though (lacking finding a mailing list more
> | suitable than this - is there one?), is to what extent are the various
> | allocations in the 232/8 to 238/8 range actually used today, and for
> | what?
> |
> |
> | --
> | Make Music, Not War
> |
> | Dave Täht
> | CTO, TekLibre, LLC
> | https://urldefense.com/v3/__http://www.teklibre.com__;!!NEt6yMaO-gk!ToLvTOd6t8dQ1-sH4XmghgDQrcb4JVFwnxuPeA-h4IwQmqxaVhSKHdAeEcHC_4g$
> | Tel: [phone]
> |
> | _______________________________________________
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> | https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/mboned__;!!NEt6yMaO-gk!ToLvTOd6t8dQ1-sH4XmghgDQrcb4JVFwnxuPeA-h4IwQmqxaVhSKHdAe8DjJ-24$
> |



-- 
Make Music, Not War

Dave Täht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: [phone]

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