[Bug Report] ----------------------------- Category: Other Package: ns 2.34 OS: LINUS UBUNTU Environment Variables: LD_LIBRARY_PATH= TCL_LIBRARY= TK_LIBRARY=
----------------------------- Description: Hallo, Description of Problem: I am doing my master thesis in detecting some kind of attacks in wireless mesh networks using AODV routing protocol. I have a small topology of 10 nodes with 6 flows as seen at the bottom. In general, The problem occurs when a node is a TCPSink of two different TCP flows (different flow ids), then there would be sometimes a violation in sending ACKs to the source IP. In my Simulation: $node_(5) is a destination of two different TCP flows with (saddr=3,flowid=2) and (saddr=9,flowid=5). When $node_(5) receives a TCP packet from saddr=9, then it sends an ACK with the TCP/IP header of the other flow (saddr=3,flowid=2) except the flowid, which stays 5. I think, this problem does not depend on my c++ code, as I only work on the routing layer and I didnt modify in tcp files. Moreover, the events of reception of a tcp packet and sending an ACK occuer simultaenously in ns2. Here is the corresponding part in the trace file: s -t 21.612927136 -Hs 4 -Hd 5 -Ni 4 -Nx 337.50 -Ny 258.79 -Nz 0.00 -Ne -1.000000 -Nl MAC -Nw --- -Ma 1aa -Md 5 -Ms 4 -Mt 800 -Is 9.0 -Id 5.0 -It tcp -Il 178 -If 5 -Ii 0 -Iv 28 -Pn tcp -Ps 72 -Pa 0 -Pf 2 -Po 0 r -t 21.613735941 -Hs 5 -Hd 5 -Ni 5 -Nx 387.75 -Ny 495.16 -Nz 0.00 -Ne -1.000000 -Nl MAC -Nw --- -Ma 1aa -Md 5 -Ms 4 -Mt 800 -Is 9.0 -Id 5.0 -It tcp -Il 120 -If 5 -Ii 0 -Iv 28 -Pn tcp -Ps 72 -Pa 0 -Pf 3 -Po 0 s -t 21.613745941 -Hs 5 -Hd -2 -Ni 5 -Nx 387.75 -Ny 495.16 -Nz 0.00 -Ne -1.000000 -Nl MAC -Nw --- -Ma 0 -Md 4 -Ms 5 -Mt 0 -Is 0.0 -Id 0.0 -It ackTBM[meane link layer ACK] -Il 52 -If 0 -Ii 0 -Iv 0 r -t 21.613760941 -Hs 5 -Hd 5 -Ni 5 -Nx 387.75 -Ny 495.16 -Nz 0.00 -Ne -1.000000 -Nl AGT -Nw --- -Ma 1aa -Md 5 -Ms 4 -Mt 800 -Is 9.0 -Id 5.0 -It tcp -Il 120 -If 5 -Ii 0 -Iv 28 -Pn tcp -Ps 72 -Pa 0 -Pf 3 -Po 0 s -t 21.613760941 -Hs 5 -Hd -2 -Ni 5 -Nx 387.75 -Ny 495.16 -Nz 0.00 -Ne -1.000000 -Nl AGT -Nw --- -Ma 0 -Md 0 -Ms 0 -Mt 0 -Is 5.0 -Id 3.1 -It ack -Il 40 -If 5 -Ii 8406 -Iv 32 -Pn tcp -Ps 353 -Pa 0 -Pf 0 -Po 3 /*SAME FLOW ID=5, BUT WITH seqno and daddr of FLOW ID 2*/ r -t 21.614162747 -Hs 4 -Hd -2 -Ni 4 -Nx 337.50 -Ny 258.79 -Nz 0.00 -Ne -1.000000 -Nl MAC -Nw --- -Ma 0 -Md 4 -Ms 5 -Mt 0 -Is 0.0 -Id 0.0 -It ackTBM -Il 52 -If 0 -Ii 0 -Iv 0 s -t 21.614531941 -Hs 5 -Hd 6 -Ni 5 -Nx 387.75 -Ny 495.16 -Nz 0.00 -Ne -1.000000 -Nl MAC -Nw --- -Ma 1aa -Md 6 -Ms 5 -Mt 800 -Is 5.1 -Id 6.0 -It tcp -Il 198 -If 3 -Ii 8261 -Iv 30 -Pn tcp -Ps 1638 -Pa 0 -Pf 0 -Po 1 The following is the tcp connections file: set tcp_(0) [$ns_ create-connection TCP $node_(3) TCPSink $node_(2) 1] $tcp_(0) set window_ 32 $tcp_(0) set packetSize_ 100 set ftp_(0) [$tcp_(0) attach-source FTP] $ns_ at 1.51380664553204 "$ftp_(0) start" # # set tcp_(1) [$ns_ create-connection TCP $node_(3) TCPSink $node_(5) 2] $tcp_(1) set window_ 32 $tcp_(1) set packetSize_ 100 set ftp_(1) [$tcp_(1) attach-source FTP] $ns_ at 5.32210428562112 "$ftp_(1) start" # # set tcp_(2) [$ns_ create-connection TCP $node_(5) TCPSink $node_(6) 3] $tcp_(2) set window_ 32 $tcp_(2) set packetSize_ 100 set ftp_(2) [$tcp_(2) attach-source FTP] $ns_ at 7.50862173200986 "$ftp_(2) start" # # set tcp_(3) [$ns_ create-connection TCP $node_(8) TCPSink $node_(7) 4] $tcp_(3) set window_ 32 $tcp_(3) set packetSize_ 100 set ftp_(3) [$tcp_(3) attach-source FTP] $ns_ at 10.9482389376257725 "$ftp_(3) start" # # set tcp_(4) [$ns_ create-connection TCP $node_(9) TCPSink $node_(5) 5] $tcp_(4) set window_ 32 $tcp_(4) set packetSize_ 100 set ftp_(4) [$tcp_(4) attach-source FTP] $ns_ at 17.72468331676194 "$ftp_(4) start" # # set tcp_(5) [$ns_ create-connection TCP $node_(8) TCPSink $node_(9) 6] $tcp_(5) set window_ 32 $tcp_(5) set packetSize_ 100 set ftp_(5) [$tcp_(5) attach-source FTP] $ns_ at 21.3301692899922699 "$ftp_(5) start" I hope that the above information is sufficient. Do you have any explanation why this tcp violation occurs?!! Regards, Qassem -- Qassem Abu Ahmad Student of computer science RWTH-Aachen University
