Order
- IP IGP routing protocols build the ip tables.
- LSR assign a local label for each route learned(but not bgp learned routes)
- LSRs share their labels with other LSRs using LDP
- LSRs build their own LIB(Label Information Base), LFIB(Label Forward Information Base) & FIB(Forward Information Base) based on what they have learned from their LDP neighbor.
- Hellow Messages
- LDP link hello uses destination UDP port 646 & is sent to 224.0.0.2 every 5 sec.
- Session is TCP based on destination port 646.
- Router with highest LDP router ID(Active LSR) will initiate TCP session.
- Keepalives are sent for every 60 sec.