How to simulate a large file transfer in Dynamips?

Hi All,

I have just started running through the Ver 5 Vol 1 QoS Aplha labs and was wondering if anybody had come up with an alternative to copying the contents of Flash from R1 down to SW2 given that the IOS is not stored in Flash with Dynamips?  If you have tried following the Labs you will know where I am coming from ;-) , otherwise this is the plot.  To simulate placing a continuous stream of traffic (non-icmp) on the Network a HTTP copy is issued from SW2 copying the contents of R1's IOS over the R4 > R5 P-2-P link.  Anybody have any ideas what I/we could use as an alternative to copying the IOS from R1 > SW2 to generate a constant stream of non-icmp traffic?




  • stepomfret: I use the Cisco built-in TTCP command line tool to simulate TCP/UDP traffic. Connect your workstation loopback adaptor into the dynamips lab as a source or sink, and use a router as the other end. If you're running a 12.3 or 12.4 T build you should be able to access the IOS tool using "ttcp" from exec mode. On your workstation you can D/L the TTCP tool (google TTCP). One side is the source and the other a sink. You can then use the tool to xfer any size data buffer using TCP or UDP across and port you wish. The tool also supports multicast to test PIM/IGMP.



  • stepomfret: Forgot to mention the TTCP command is hidden, so tabbing for "t" or using "?" yields no luck. Just type "ttcp <ENTER>" from priv exec and follow the prompts.



  • Start a TFTP server on the PC you are running dynamips. Assign an address to your PC's looback  (i.e MSLoopback if Windows). Have the TFTP server be bound to your loopback's address.  Have a large file (for example an IOS image) on your PC that the TFTP server will transfer. Configure one of your routers in your .NET file to have one of its interfaces connected to your PCs loopback. For example, F2/0 = NIO_gen_eth:DeviceNPF_{6D02835F-A711-4387-8E53-1CE8FEE50CDF}. You are now ready to do a copy tftp flash: from the TFTP server on your PC to this router.

  • me too i got some problems simulating large HTTP transfers on QOS v5 book.

    if you are running dynamips on ubuntu you can connect your virtual routers to the tap0 interface, following this simple tutorial


    after doing this, you can install tftpd and micro-httpd via synaptic/apt.

    tftp root directory will be /srv/tftp,

    micro-httpd root will be /var/www, both of them are configurable via /etc/inetd.conf , inetd service must be started by hand from /etc/init.d

    R0#copy null:
    Loading !!!!!!!!!!!
    43994 bytes copied in 0.144 secs (305514 bytes/sec)

    just my 2 cents here, [H] 



    mini-httpd si better than micro one, it supports larger files transer.

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