
156 ◾ IP Communications and Services for NGN
a matching FEC. e tables also show the mapping between the input port of the
router and input label, and the output port and output label. is information in
the table is refreshed whenever a renegotiation of the label bindings takes place.
Creating the LSP
is step follows the creation of all the LIBs. It is undertaken in the reverse direction,
from the egress LER back through the core network to the ingress LER. In Figure 7.19,
this is equivalent to starting at LER4 and LSR2, LSR1, and then LER1.
Inserting the Labels and Table Lookup
e ingress router (an LER) (Figure 7.19) uses the LIB table to ...