An EOIP will go thru a smaller MTU that is entirely the point of the standard as you note but it's not a magician the only way it achieves that trick is by breaking the large packet into multiple smaller packets.
Its basic physics If you have a sofa and it's bigger than the door the only way you can move the sofa thru the door is in pieces or make the door bigger.
Take your 1400 MTU to get a 1542 packet thru it then you have to have two packets 1400 + 142 .. should be easy to understand.
So now imagine a queue trying to limit to 1500 bits per second the queue would allow the first 1400 packet thru wait for 1 second then allow the 142 bit packet thru then it would rinse and repeat. Net result you get half the queue speed (1542bits every 2 seconds aka 771 bits per second) and not what you expected because of the overhead of the packet split.
Now goto the mikrotik queues and look at how it works
https://wiki.mikrotik.com/wiki/Manual:H ... _Algorithm
You have the pathological case of alternating big and small packets ...its a burst every second packet![:-)]( "Smile")
Net result is you will need to set for a burst of 20M to get a constant 10Mb etc ... so you have half queue speed as expected with the default queue settings and is explained in the manual.
Its basic physics If you have a sofa and it's bigger than the door the only way you can move the sofa thru the door is in pieces or make the door bigger.
Take your 1400 MTU to get a 1542 packet thru it then you have to have two packets 1400 + 142 .. should be easy to understand.
So now imagine a queue trying to limit to 1500 bits per second the queue would allow the first 1400 packet thru wait for 1 second then allow the 142 bit packet thru then it would rinse and repeat. Net result you get half the queue speed (1542bits every 2 seconds aka 771 bits per second) and not what you expected because of the overhead of the packet split.
Now goto the mikrotik queues and look at how it works
https://wiki.mikrotik.com/wiki/Manual:H ... _Algorithm
You have the pathological case of alternating big and small packets ...its a burst every second packet
Net result is you will need to set for a burst of 20M to get a constant 10Mb etc ... so you have half queue speed as expected with the default queue settings and is explained in the manual.
Statistics: Posted by LdB — Thu Jan 04, 2024 3:21 pm