{"id":187,"date":"2018-02-11T00:06:15","date_gmt":"2018-02-11T00:06:15","guid":{"rendered":"https:\/\/www.kuncar.net\/blog\/?p=187"},"modified":"2018-11-01T00:11:54","modified_gmt":"2018-11-01T00:11:54","slug":"packeth-tutorial-part-ii-the-gen-bgen-s-and-pcap-options","status":"publish","type":"post","link":"https:\/\/www.kuncar.net\/blog\/2018\/packeth-tutorial-part-ii-the-gen-bgen-s-and-pcap-options\/","title":{"rendered":"PackEth tutorial part II \u2013 The Gen-B,Gen-S and PCAP options"},"content":{"rendered":"
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\"\"This is a Second part of an article I have written some time ago about the great tool called\u00a0<\/span><\/span>PackETH<\/a>. \u00a0This article will be much shorted as it will be focused on the less complicated (but not useful!) modes of the tool.<\/span><\/span><\/div>\n<\/header>\n
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In the previous par I have described how to build your own packet from L2 to L4 but what if you need something else ? maybe not a single packet but a burst of packets? or what is you need to send multiple streams of various frames ? Well then you need to use the Gen-S and Gen-B modes.<\/span><\/p>\n

GEN-B<\/h3>\n

The name stands for Generate burst. The necessary prerequisite for using this mode is for you to have a ready and valid packet loaded in the Builder mode. Once you have that you can run the burst generation. This is how the GUI looks like:<\/span><\/p>\n<\/div>\n

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The \u201cNumber of packets\u201d field is I think rather self-explanatory. The second is more interesting and deserves our attention as it can be used for buffer testing. The \u201cDelay between packets\u201d field is actually referring to what is correctly called the Inter Frame Gap (IFG) which is a delay between end of one frame and beginning of the next one. The physical media has a limitation of how fast you can the frames be send. Then the \u201cmax speed\u201d check box is in effect it means you will send all the frames with minimal IFG. This situation is also be known as back-to-back scenario. \u00a0Under normal circumstances the frames would not be played out from the buffer like this unless the buffer would be full. So you are asking what is this good for ? Well the traffic can be very bursty and the software on your network equipment might not be able to handle it very well so testing this behavior before you introduce new equipment into your network is highly recommended (and is actually standardized as part of\u00a0RFC 2544<\/a>\u00a0test suite).<\/span><\/p>\n

The other interesting thing you can do in Gen-B mode is to change the frame\u2019s content on fly (from the original you\u2019ve build in the Builder mode). The things you can do with it are quite wild. let\u2019s have a look at the options and what they do:<\/span><\/p>\n