So I have had many conversation over the years in regards of that is MTU and how does it work and what is the relationship between frame/packet/datagram sizes. Despite the fact that this is actually fairly simple there seems to be a lot of confusion on this topic so that is why this article come about.
Lately there has been yet again a big surge of interest in IPv6 and I did find to my surprise that even thought IPerf supports IPv6 for quite some time no-one actually has written how to actually do this rather trivial test.
First thing about IPv6 is that your interface on the end-point PCs will auto-assign a link-local address to itself. The link local address is in fe80::macaddress format (where one bit of the mac address can be changed depending on the implementation). So this looks fine – no problems. You should be able to ping between those ip addresses using ipv6 ping riight? Lets try to ping localhost’s ipv6 link-local address. In order to do this you need to specify the interface you are using as ping can’t lookup the address automatically as it can with IPv4.
This is a Second part of an article I have written some time ago about the great tool called PackETH. This article will be much shorted as it will be focused on the less complicated (but not useful!) modes of the tool.
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.
mac-address max-mac-count 5
So now with the limit in place I would like to test it. The first thought was to use Linux alias as a fast and dirty way of doing this but unfortunately I soon found out that tit doesn’t allow for the requirements I had in mind.