Hello Narad
Yes. For more about the use of RSVP in this role, take a look at this post. MP-BGP is used to exchange VPN labels for MPLS layer 3 VPN about which you can learn more at this lesson:
Implicit null has a value of 3 while explicit null has a value of 0.
According to RFC3032:
A value of 0 represents the “IPv4 Explicit NULL Label”. This label value is only legal at the bottom of the label stack. It indicates that the label stack must be popped, and the forwarding of the packet must then be based on the IPv4 header.
In order for LDP to function correctly, and for MPLS to operate correctly, you require full internal routing within the MPLS core network. BGP will only provide routing for the network edge, that is, the PE routers and the networks they connect. Remember, BGP itself also requires that routing be already established within the MPLS core network either using static routing or some IGP.
You can find more information about it at this Cisco documentation:
Fate sharing involves the creation of shared-risk link groups or SRLGs. These groups are used in situations where links in a network share a common fiber or a common physical path. These links have shared risk, and thus when one link fails, other links in the group also fail.
Using these SRLGs, we can configure auto backup path computation. When fate sharing is activated, links are assigned one or more numbers to represent risks. When two links are assigned a common number then this indicates that these two links are sharing fate. If one of those links fails, then the others, which share the same fate, will also be excluded from the topology. More info can be found here:
I hope this has been helpful!
Laz