Eliminating the trailers and header

Question

State what are the trailers and header and how are they generally added and eliminated?

Answer 1

Every layer within the sending machine append its own information to the message it receives from the layer immediately above it and passes the whole package to layer just immediately below it. This information is appended in the form of headers or trailers. Headers are added within the message at the layers 6,5,4,3, and 2. A trailer is added at the layer2. At receiving machine, the headers or trailers attached to the data unit at corresponding sending layers are isolated, and actions suitable to that particular layer are taken.