BGP vs Bellman-Ford: Counting to Infinity

After a link fails, Bellman-Ford loops forever counting up. Path-vector (BGP) detects the loop in 1 step by checking if its own ID appears in the advertised path.

Bellman-Ford: Counting to Infinity

Initial state: V→T=1, S→T=2 (via V).

BGP Path-Vector: Instant Detection

Initial state: V→T=1, S→T=2 (path [S,V,T]).

Step 0

Router S

Router V

Destination T

Failed link / loop arrow