[j-nsp] Segment Routing ( SPRING )

[Clarke Morledge]

I am working my way through _MPLS in the SDN Era_, and I really am 
intrigued by what I read about SPRING.

I got burned a few years ago trying to deploy RSVP for traffic engineering 
purposes, and I ran into so many serious JUNOS bugs, I had to abandon it 
and use LDP to handle labels and stick with IGP metric manipulation to do 
some basic traffic enginering.  Since I do not need bandwith reservation, 
I have actually appreciated the simplicity of LDP.  But it looks like 
SPRING does pretty much the same thing, with less control plane overhead, 
which is even more attractive.

I have a few questions for those who might know:

(a) How mature is SPRING, considering that the ISIS IGP it is built on is 
well-established?

(b) Are there any noticeable behavioral differences between SPRING and LDP 
implementations?

(c) Do we have any idea when P2MP LSPs will come along with SPRING? Will 
it need to be coupled somehow with PIM?

Thanks.

Clarke Morledge
College of William and Mary
Information Technology - Network Engineering
Jones Hall (Room 18)
Williamsburg VA 23187