An example of bi-directional LSP setup using LDP protocol.
An MPLS cloud with 5 LSRs where data from two TCP clients must transit to get two
their destination address.

The LDP is hop-by-hop and operates in downstream-on-demand mode.

The first TCP client(host1) sends its data to host4. The data is queued at LSR1
till the LDP daemon successfully setups a path asscociated the FEC of the packets'
destination (destination FEC.)


