Have you ever got confused with which of the Segment, Packet, Frame and Bit goes with Transport, Network, Data link and Physical layer?? Look no futher. Here'a little trick I came up with recently.
4.Transport______(S)egments
3.Network_______(P)ackets
2.Data Link______(F)rames
1.Physical_______(B)its
Take the first letters and put them in alphabetic order.

Thanks.