Hi, all, The following is a line in file "out.nam" generated by "ns srm.tcl". Would you please explain it if anyone knows, especially "-y {3 2.1}"? Thank you very much in adance! r -t 2.12876 -s 2 -d 0 -p SRM -e 68 -c 40 -i 82 -a 0 -S 0 -f 0 -m 1 -y {3 2.1} Cheers Cheng Liang