Relaxing an edge asks whether reaching a neighbor through the current router improves the known distance. This topology includes one visible improvement for E.

highlighted = computed this step

C proposes E

C reaches E with distance 7 through the C-E edge.

d(E)=7d(E)=7
Relaxing edgesThe router topology is validated as exact nonnegative integer-weighted edges.Relaxing edges - weighted undirected topology4251035157ABCDEF

Show the first E claim

That claim is C's final distance 2 plus edge C-E weight 5, giving 7.

2+5=72+5=7
Relaxing edgesThe router topology is validated as exact nonnegative integer-weighted edges.Relaxing edges - weighted undirected topology4251035157ABCDEF

D improves E

Later D reaches E with distance 6 through the D-E edge.

d(E)=6d(E)=6
Relaxing edgesThe router topology is validated as exact nonnegative integer-weighted edges.Relaxing edges - weighted undirected topology4251035157ABCDEF

Show the better E claim

The D route is D's final distance 5 plus edge D-E weight 1, giving 6.

5+1=65+1=6
Relaxing edgesThe router topology is validated as exact nonnegative integer-weighted edges.Relaxing edges - weighted undirected topology4251035157ABCDEF

Keep the smaller claim

E improves because 6 is less than 7.

6<76<7
Relaxing edgesThe router topology is validated as exact nonnegative integer-weighted edges.Relaxing edges - weighted undirected topology4251035157ABCDEF

Update the predecessor too

When E improves to 6, its predecessor changes to D. That predecessor is what later appears in the tree.

pred(E)=D\text{pred}(E)=\text{D}
Relaxing edgesThe router topology is validated as exact nonnegative integer-weighted edges.Relaxing edges - weighted undirected topology4251035157ABCDEF

Summary

Relaxation replaces a tentative distance only when the new route is strictly smaller.

pred(E)=D\text{pred}(E)=\text{D}
Relaxing edgesThe router topology is validated as exact nonnegative integer-weighted edges.Relaxing edges - weighted undirected topology4251035157ABCDEF