Re: [MBONED] deprecating MSDP

On Wed, Sep 06, 2017 at 03:00:28AM -0700, Dino Farinacci wrote:
> > Running a unicast-only network is quite forgiving, running multicast for what people typically use multicast for in an ISP network, is a lot less forgiving. Upside is typically small, unless you're providing TV for a profit (I don't know of any other typical residential ISP revenue stream for multicast), it's just not worth it.

> This is why running multicast over a unicast-only overlay has the best of both worlds and reduces the cost of running multicast because you only have to debug the very edges of the network. And the closer you put the encap/decap points to sources and receivers reduces further the debug surface.

God point. Reducing the number of points in the network where you have to
deal with multicast replication state is a good thing. I don't think we have
a good complete BCP for how to best manae multicast state in SP networks. See
my prior email about amount of SSM sender and receiver state as well. 

Note though, that this is orthogonal to what Mikael mentioned. Current
IPTV style apps without any transport reliability (FEC, fountain codecs,
etc. pp) will also fail miserably when they are tunneled across unicast.
The only place where unicast tunneling magically solves the reliabilty issues
is on WiFi ;-)

Btw: just seeing that no document claims to be updating RFC3170. Does that not say everything about the state of IP multicast apps ? ;-))

Cheers
    Toerless

> Dino
> 
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