The IP protocol can handle fragmentation and it includes the fragmentation offset and identifier. I know this comes into play when your IP packet is too big for some specific network or link where the MTU is lower then the previous one.

For example, the MTU is 1000 bytes, and your IP packet is 900 (+20) bytes. Further down the line the MTU is only 500, so you have to extract the IP data and put it into two packets, one of them 480 (+20), and the other one 420 (+20).

But from my understanding this is fragmentation in the Networking layer, turning an IP packet into multiple IP packets. Meaning that you only have the Transport Layer Header present one time, and a new Network layer header for each smaller IP packet.

I hope my understanding of this is correct. Anyway, after the image comes my actual question:

[![enter image description here](https://i.stack.imgur.com/FcsL4.png)](https://i.stack.imgur.com/FcsL4.png)

Let's say your IP packet length is limited by 1000 bytes including the header, due to the MTU of 1000 bytes.

What actually happens if for some reason your TCP segment is bigger than 980, thus exceeding the maximum IP packet size? 

What if your TCP segment is 1960 bytes. How is the fragmentation handled here? Is it put into a 1980 IP packet, which is then fragmented into two 980 (+20) IP packets?

Does the fragmentation occur before this, in the transport layer? Are multiple smaller transport layer segments, each with its own header sent into the IP layer with the correct size?