why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?)

Mon Jun 22 14:30:45 UTC 2020

> Masataka Ohta
> Sent: Monday, June 22, 2020 1:49 PM
> 
> Robert Raszuk wrote:
> 
> > Moreover if you have 1000 PEs and those three sites are attached only
> > to 6 of them - only those 6 PEs will need to learn those routes (Hint:
> > RTC -
> > RFC4684)
> 
> If you have 1000 PEs, you should be serving for somewhere around 1000
> customers.
> 
> And, if I understand BGP-MP correctly, all the routing information of all
the
> customers is flooded by BGP-MP in the ISP.
> 
Not quite,
The routing information is flooded by default, but the receivers will cherry
pick what they need and drop the rest. 
And even if the default flooding of all and dropping most is a concern -it
can be addressed where only the relevant subset of all the routing info is
sent to each receiver.
The key takeaway however is that no single entity in SP network, be it PE,
or RR, or ASBR...., ever needs everything, you can always slice and dice
indefinitely.
So to sum it up you simply can not run into any scaling ceiling with MP-BGP
architecture.   

adam