Thanks for your reply.
As you mentioned, information inside the RIB is use to build the LIB.
So i would imagine to have a LABEL for all the available routes.
e.g. I have 3 best routes to the same destination with rip, eigrp, ospf in the RIB.
192.168.0.0/24 via 192.168.1.1 - rip
192.168.0.0/24 via 192.168.2.1 - eigrp
192.168.0.0/24 via 192.168.3.1 - ospf
q1) Can i check for FIB, does it contain the same amount of available routes as in the RIB ?
q2) if the above is yes, i would believe FLIB and FIB would have the same amount of labels ?
q3) it is said that in MPLS, the LABELs are use to do switching/routing from Source to Destination and it is faster because there is no need to do best route selection using the IP headers. – is this true ?
But how do we ensure that the LABELs being used (added) and the next hop to send to represent the best routing path available ?
or to put it in another way
- in normal routing, best route selection is done via (ad, metric, prefix length)…
- in mpls, since all available routes will have a tag, how does the router know which tag to use (without looking at the routing table for the best route) ?