Correlation　of　network　nodes　based　on　RTT　is　quantified　by　the　similarity　metric　which　is　defined　as　the　extent　to　which　two　source　nodes　have　the　same　changing　trends　of　RTT　to　the　same　destination　node.　By　this　definition,　the　correlation　between　path　load　and　similarity　is　analyzed　in　this　paper　along　with　the　effects　of　path　length　on　the　correlation,　such　as　the　order　of　the　load　combinations　and　the　condition　regarding　path　load　and　length　for　getting　a　strong　similarity.　Factor　analysis　on　the　load　reduces　the　27　load　combinations　to　2　factors,　i.e.,　the　heavy　common　load　and　heavy　private　load,　respectively,　which　dominate　the　similarity.