Hi ns-users, In my script I would want set up the Access Point with 2 interfaces in 2 different channels (chan_a,chan_b), one with the standard 802.11a and the other second standard 802.11b. Please, I have need help in order to understand if my configuration is correct! If isn't, can you give a suggestion to me? (in my script the configuration of the nodes follows mw-node) My script: global val_ set val_(channel) Channel/Wireless ;# channel set val_(propagation) Propagation/TwoRayGround ;# radio-propagation model set val_(phy) Phy/WirelessPhy ;# physical layer set val_(mac) Mac/802_11 ;# mac layer set val_(ifq) Queue/DropTail/PriQueue ;# interface queue type set val_(ll) LL ;# link layer type set val_(antenna) Antenna/OmniAntenna ;# antenna model set val_(ifqlen) 50 ;# max packet in ifq set val_(routing) None ;# routing set val_(nMn) 2 set val_(nAP) 2 set val_(x) 150 set val_(y) 150 set val_(tr) esercizi/out5.tr ;# trace file set val_(namtr) esercizi/out5.nam ;# nam trace file set val_(stopTime) 15 set chan_a [new $val_(channel)] set chan_b [new $val_(channel)] ............ ........ $ns_ wireless-config -routing $val_(routing) \ -mac $val_(mac) \ -phy $val_(phy) \ -propagation [new $val_(propagation)] \ -topography $topography_ \ -ll $val_(ll) \ -ifq $val_(ifq) \ -ifq-length $val_(ifqlen) \ -antenna $val_(antenna) \ -xyz-trace on \ -ifq-trace on \ -mac-trace on \ -rtm-trace on \ -eot-trace off #---portal node $ns_ node-config -wireless +Portal ;# enable Portal support for {set i 0} {$i<$val_(nAP)} {incr i} { ;#ACCESS POINT $ns_ wireless-config -channel $chan_a set node_AP($i) [$ns_ node 1.[expr $i+1].0] $node_AP($i) set-position [expr 100.0*$i*$i] 100.0 0.0 set netif_a($i) [$node_AP($i) add-interface "Wireless"] ;# add wireless interface ##802.11a set mac_a($i) [new $val_(mac)] $mac_a($i) set SlotTime_ 0.000050 ;# 50us $mac_a($i) set SIFS_ 0.000028 ;# 28us $mac_a($i) set PreambleLength_ 0 ;# no preamble_ $mac_a($i) set PLCPHeaderLength_ 128 ;# 128 bits $mac_a($i) set PLCPDataRate_ 1.0e6 ;# 1Mbps $mac_a($i) set dataRate_ 54.0e6 ;# 54Mbps $mac_a($i) set basicRate_ 1.0e6 ;# 1Mbps $netif_a($i) set Pr_ 8.9175e-10 $netif_a($i) set Pt_ 0.2818 $netif_a($i) set freq_ 5.0e+9 $netif_a($i) set RXThresh_ 1.60607e-10 $netif_a($i) set CSThresh_ [expr 0.9*[$netif_a($i) set RXThresh_]] $mac_a($i) netif $netif_a($i) $ns_ wireless-config -channel $chan_b set netif_b($i) [$node_AP($i) add-interface "Wireless"] ;# add wireless interface ##802.11b/g $netif_b($i) set Pr_ 8.9175e-10 $netif_b($i) set Pt_ 0.007214 $netif_b($i) set freq_ 2.4e+9 $netif_b($i) set RXThresh_ 7.138e-11 $netif_b($i) set CSThresh_ [expr 0.9*[$netif_b($i) set RXThresh_]] $netif_b($i) set DSSS_CWMin 15 $netif_b($i) set DSSS_CWMax 1023 $netif_b($i) set DSSS_SlotTime 0.000009 $netif_b($i) set DSSS_CCATime 0.000003 $netif_b($i) set DSSS_RxTxTurnaroundTime 0.000002 $netif_b($i) set DSSS_SIFSTime 0.000016 $netif_b($i) set DSSS_PreambleLength 96 $netif_b($i) set DSSS_PLCPHeaderLength 40 $netif_b($i) set DSSS_PLCPDataRate 6.0e6 ;#// 6Mbps $netif_b($i) set DSSS_MaxPropagationDelay 0.0000005 ;# // 0.5us set mac_b($i) [new $val_(mac)] $mac_b($i) set SlotTime_ 0.000020 ;# 20us $mac_b($i) set SIFS_ 0.000010 ;# 10us $mac_b($i) set PreambleLength_ 144 ;# 144 bits preamble $mac_b($i) set PLCPHeaderLength_ 48 ;# 48 bits $mac_b($i) set PLCPDataRate_ 1.0e6 ;# 1Mbps $mac_b($i) set dataRate_ 11.0e6 ;# 11Mbps oppure 54Mbps(802.11g) $mac_b($i) set basicRate_ 1.0e6 ;# 1Mbps $mac_b($i) netif $netif_b($i) } .......... ......... thanks thanks thanks Elena