This memo provides an analysis of the hash-threshold method for selecting the next-hop in equal-cost multi-path (ECMP) routing. The hash-threshold method involves hashing packet header fields to determine a key, which is then used to select a region in the key space corresponding to one of the next-hops. The analysis covers the performance and disruption caused by changes to the set of next-hops. Performance is assessed based on the computational requirements, while disruption is measured as the fraction of flows whose paths change due to changes in the router. The analysis shows that the hash-threshold method performs well with equal-sized regions and has minimal disruption, making it a suitable choice for ECMP routing. The memo also compares hash-threshold to other algorithms like modulo-N and highest random weight, highlighting their respective advantages and disadvantages in terms of performance and disruption.This memo provides an analysis of the hash-threshold method for selecting the next-hop in equal-cost multi-path (ECMP) routing. The hash-threshold method involves hashing packet header fields to determine a key, which is then used to select a region in the key space corresponding to one of the next-hops. The analysis covers the performance and disruption caused by changes to the set of next-hops. Performance is assessed based on the computational requirements, while disruption is measured as the fraction of flows whose paths change due to changes in the router. The analysis shows that the hash-threshold method performs well with equal-sized regions and has minimal disruption, making it a suitable choice for ECMP routing. The memo also compares hash-threshold to other algorithms like modulo-N and highest random weight, highlighting their respective advantages and disadvantages in terms of performance and disruption.