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

[Leonard Giuliano <[e-mail]>]

Previously, I would say 233/8 was probably the most validly used block for 
ASM traffic.  234/8 was useful for those sources that didn't have their 
own AS#, but most of the players on the MBONED who do source did have an 
AS#, so I suspect it never got wide usage.

Going forward, 232/8 should be the widest used block as SSM has been the 
recommended model for interdomain mcast.

Last year, William Zhang wrote a script to curate all the content on the 
MBONE.  His results for all the mcast streams with >5pps can be found 
here:

https://raw.githubusercontent.com/willzhang05/senior-research/master/logs/results.txt

Essentially, this looked at active multicast streams on the I2 Looking 
Glass (https://routerproxy.wash2.net.internet2.edu/routerproxy/).



On Wed, 18 Dec 2019, Dave Taht 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]
| > |
| > | _______________________________________________
| > | MBONED mailing list
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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
| https://urldefense.com/v3/__http://www.teklibre.com__;!!NEt6yMaO-gk!W0hgHVMJLatcKw6yFET8wtPoL5C-Tj6-d0UDjHqOKeo7pttN6GAamhtiVuKOj08$ 
| Tel: [phone]
|