MACs are used at layer 2, Labels are used right after the layer 2 header and before the layer 3 header. Its called layer 2.5

R3 knows where to send packets because each route in the routing table is assigned a label, R1 and R5 build a multi-protocol BGP VPN tunnel to each other and attach labels destined to each other, the routers in between so those labels and forwards packets accordingly.

R3 does not know the destination. all P routers share “hey these are the prefixes I support, if you want to send traffic to this or that send me this or that label (typically just loopback).. so if pc6 is sending traffic to pc7 (which is transit traffic) only the PEs should know the routes, R1 has the destination learned via ibgp with next hop of R5 loopback, so that route on R1 has destination can be reached via R5 but next hop is the LSP.. so all transit routes in the mpls core will only inspect labels, they do not inspect L3 (if they do so, traffic will be dropped because the source and destination prefixes are only learned on the edge via ibgp)

Gns3

@@ccnpseth4563 .. Does installation of GNS3 slows down ur PC ?

@@aniketwanjari2624 not really, minimum is 8GB RAM, but if you try to run more routers then it will slow down, be careful if a idle PC value is not set, it will send your laptop into smokes

Thank you for the feedback, glad you enjoyed it

Cutie Pie very nice explanations.