On Tuesday 30 January 2007 11:33, Jon Etkins wrote: > Though it hurts my pride to have to say it, I could use some pointers, > too. I've installed NISTnet on a dual-NIC SLES10 box for the purpose of > simulating a T1 WAN link in our lab
That's probably where most people run into a bit of trouble. NISTnet is great for introducing delay, packet loss, jitter, and bandwidth limits etc but it's better to leave the job of bandwidth management to edge connected routers. If you set bandwidth on NISTnet, the result will just show you what the impact is of mismatched network speeds - packets queue up in the NISTnet box if packets arrive faster than the bandwidth setting. If the mismatch is serious - the queue grows large fast and delays get silly (box will probably crash). To emulate a T1, set up 3 boxes (A,B,C) with A connected to C through B (NISTnet = B). Without activating NISTnet, make that look like a T1 connection between A and C. When that's working, activate NISTnet and introduce whatever delay, etc you want. Now your T1 will have delay and packet loss and jitter. If you can't get that basic link to work right without nistnet, then your trouble is in basic networking and NISTnet can't help you with that. (Before I get corrected - you can do it with 2 boxes too but it's intuitively easier to understand what's happening if the NISTnet box is "the WAN") If you do not manage the bandwidth limit at the edge of the network, and use NISTnet to limit bandwidth, you will have to make sure that the average traffic bitrate does not exceed the bandwidth limit or else packets will start to queue up - just like what would happen on a real network. NISTnet will provide you some useful queing stats if your traffic is "bursty" but still stays within the bandwidth limits (on average) - the queue will grow and shrink with the bursts. As for tutorials - try google . . . for example this link: http://www.linuxdevcenter.com/pub/a/linux/2000/06/22/LinuxAdmin.html Hope that helps . . . Cheers; Alex V. Avantel Systems ============ > , but my initial testing - trying to > introduce delay and packet loss while constantly pinging a remote host - > doesn't appear to be working. I'm sure I could probably muddle through it > eventually, but we (a) we need this working quickly for a current project, > and (b) why reinvent the wheel if the information is already out there. > > Thanks in advance, > ---------------------------- > Jon Etkins > Austin ITSO IT Support Specialist > 512-838-7731 (T/L: 678-7731) > [EMAIL PROTECTED] > > > > > > "Imad Ajarmeh" <[EMAIL PROTECTED]> > Sent by: [EMAIL PROTECTED] > 01/30/2007 04:20 AM > > To > nistnet@antd.nist.gov > cc > > Subject > [nistnet] please help. nistnet tutorial > > > > > > > hello everybody. > iam a new member here, > i have just configured and installed nistnet 2.0.12c on my FC4 (2.6.11) > it seems to be working fine. > i need some tutorials on nistnet usage. please > my goal is to simulate VOIP traffic > > -- > Imad Ajarmeh _______________________________________________ > nistnet mailing list > nistnet@antd.nist.gov > http://www-x.antd.nist.gov/mailman/listinfo/nistnet -- This message has been scanned for viruses and dangerous content by Avantel Systems, and is believed to be clean. _______________________________________________ nistnet mailing list nistnet@antd.nist.gov http://www-x.antd.nist.gov/mailman/listinfo/nistnet
