All things related to multicast

[Leonard Giuliano <>]

FWIW, at the last MBONED mtg, a draft was presented to explicitly 
recommend alot of what is suggested below.  Specifically, that SSM should 
be the only service model for interdomain deployments.  Would love 
comments and feedback from folks here on this draft (send to 
):

https://www.ietf.org/id/draft-acg-mboned-multicast-models-00.txt

Personally, I would go a few steps further and would love to see 
network-based source discovery completely deprecated (inter- and 
intradomain).  We don't expect routers to track all the unicast sources on 
the Internet- we let Google do that- so why do it for mcast?  The 
application layer is where source discovery belongs- it is where you can 
get the most scale, robustness, flexibility, creativity and room for 
innovation.  Multi-source apps like beacon would still work if you let the 
app layer learn of the sources, and you can radically simplify the network 
by just doing SSM (no shared trees, no RPs, no MSDP, no register 
encap/decap, no tree switchover, no data-driven state creation, etc).

The history of networking suggests a tendency towards connecting more 
things over time.  Perhaps multicast will be the exception- thus far, it 
has mostly seemed to go that way.  But I would point out that it wasn't 
too long ago that IPv6 faced a similiar ennui and most evidence at the 
time pointed to IPv6 never taking off.  However, IPv6 seems to have turned 
a corner in recent years and appears to be making real strides in 
deployment.  For those out there who are still interested in seeing 
Internet Mcast become a reality, might be worth looking at what got IPv6 
over the hump.  Maybe it was the fear of impending doom from those ominous 
Address Exhaustion countdowns, maybe it was World IPv6 Day, maybe it was 
just a few large content entities throwing their weight behind v6, 
whatever it was (and I'm curious myself), perhaps there are some lessons 
to be learned and applied in the case of Internet Mcast.  After all, every 
argument (pro and con) one could make about IPv6 is equally applicable, if 
not moreso, to it's technological cousin, Internet Mcast.

-Lenny

On Wed, 10 Aug 2016, Alan Whinery wrote:

| 
| And also, ultimately, this is a matter for NTAC to discuss.
| 
| (exlusions of other recipients in previous unintentional. )
| 
| 
| On 8/10/2016 9:27 AM, Alan Whinery wrote:
| > Is there a current chairperson-of-record for the Multicast Group?
| >
| > Shall we put a Weekend Update: Point/Counterpoint on the Tech Exchange
| > NTAC agenda?
| >
| > I honestly don't know if there is a counterpoint. We have reached a
| > soft consensus "multicast is dead" in the IPv6 Working Group multiple
| > times.
| >
| > I just think it's worth a formal discussion, not because I disagree
| > with John or David, but because sometimes bathwater needs to be
| > checked for babies.
| >
| > On 8/10/2016 9:13 AM, David Farmer wrote:
| >> We are at the beginning of a major equipment replacement/upgrade
| >> cycle for campus.  As part of that I have been thinking about what
| >> the appropriate support of interdomain multicast should be.  While I
| >> haven't come to a final conclusions yet, here is my current thinking.
| >>
| >> 1. Primary goal of deprecating MSDP, and therefore interdomain IPv4
| >> ASM multicast. MSDP is fragile and honestly it's a hack.
| >> 2. Keep IPv4 ASM multicast locally, on campus, maybe between campuses
| >> in the University system, through use of a common RP, no MSDP.  
| >> 3. Keep IPv4 SSM interdomain multicast 
| >> 4. Focus efforts on supporting IPv6 interdomain multicast, SSM and
| >> embedded-RP
| >> 5. Keep IPv4 and IPv6 BGP multicast NLRIs
| >> 6. Primarily PIM sparse mode, maybe using PIM-bidir for better scaling
| >>
| >> What do others think?
| >>
| >> Thanks
| >>
| >> On Wed, Aug 10, 2016 at 11:00 AM, Michael H Lambert 
<
| >> 
<mailto:>>
 wrote:
| >>
| >>     The following was sent by John Kristoff (cc'ed) to the Multicast
| >>     WG mailing list (yes, the list still exists):
| >>
| >>     > Begin forwarded message:
| >>     >
| >>     > From: John Kristoff 
<
 
<mailto:>>
| >>     > Subject: AS 20130 has turned off interdomain IP multicast
| >>     > Date: 9 August 2016 at 18:09:37 EDT
| >>     > To: 
"
| >>     
<mailto:>"
 
<
| >>     
<mailto:>>
| >>     > Reply-To: 

| >>     
<mailto:>
| >>     >
| >>     >> show msdp
| >>     > MSDP instance is not running
| >>     >
| >>     >> show route table ?
| >>     > Possible completions:
| >>     >  <table>              Name of routing table
| >>     >  inet.0
| >>     >  inet.1
| >>     >  inet6.0
| >>     >  inet6.1
| >>     >>
| >>     >
| >>     > It was a fun ride for a time, but it now joins the dustbin of dead
| >>     > technologies in the back of my brain.  Token Ring, ISDN,
| >>     NetWare, ...,
| >>     > welcome you to the club, may you rest in peace.
| >>     >
| >>     > John
| >>
| >>     Does anyone else think it might be time to reflect on the future
| >>     of interdomain multicast in the backbone?
| >>
| >>     Michael
| >>
| >>
| >>
| >>
| >> -- 
| >> ===============================================
| >> David Farmer               
Email:
| >> 
<mailto:Email%>
| >> Networking & Telecommunication Services
| >> Office of Information Technology
| >> University of Minnesota  
| >> 2218 University Ave SE        Phone: 612-626-0815
| >> Minneapolis, MN 55414-3029   Cell: 612-812-9952
| >> ===============================================
| >
| >
| 
|