Split Horizon

• Alleviates (does not solve!) looping problem

• Many variants

• Don’t announce path to D on link L if some other router on L is announcing a better path on L

• If only keep single “best path”, then the link L on which you forward to D is the only one split horizon applies

A

B

C

Split horizon solves

A

B

C

D

Split horizon does not solve

3-rtr loop

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