Confirming source-routed multicast is dead on the public Internet

Aaron Gould aaron1 at
Wed Aug 1 11:21:40 UTC 2018

As you all have said, to confirm, I use ssm Mcast to distribute TV from satellite down links in the headend, out to a few different remote head ends.  From there it's converted back to RF video and sent to subscribers via cable or hfc plant


> On Jul 31, 2018, at 5:15 PM, Job Snijders <job at> wrote:
>> On Tue, 31 Jul 2018 at 23:29, Sean Donelan <sean at> wrote:
>> Its tought to prove a negative. I'm extremely confident the answer is yes,
>> public internet multicast is not viable. I did all the google searches,
>> check all the usual CAIDA and ISP sites. IP Multicast is used on private
>> enterprise networks, and some ISPs use it for some closed services.
>> I got sent back with a random comment from a senior official saying "but
>> I heard different." I bit my tongue, and said I would double (now
>> quadruple) check.
>> If any ISPs have working IP source-routed multicast on the public
>> Internet that I missed, or what I got wrong.  That's what content
>> distribution networks (cdn's) are for instead.
> AS 2914 is working to fully dismantle all its Internet multicast related
> infrastructure and configs. All MSDP sessions have been turned off, we have
> deny-all filters for the multicast AFI, and the RPs have been shut down.
> For years we haven’t seen actual legit multicast traffic. Also the
> multicast “Default-Free Zone” has always been severely partitioned. Not all
> the players were peering with each other, which led to significant
> complexity for any potential multicast source.
> Reasoning behind turning it off is that it limits the attack surface
> (multicast can bring quite some state to the core), reduces the things we
> need to test and qualify, and by taking this off the RFPs we can perhaps
> consider more vendors.
> However, as you noted; multicast within a single administrative domain
> (such as an access network distributing linear TV), or confined to
> purpose-built L3VPNs very much is a thing. On the public Internet multicast
> seems dead.
> Kind regards,
> Job

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