The layers bleed because they sometimes work together, deviating from their designated sequence. For example, a router might analyze the destination address (Network layer) before fully assembling the message (Transport layer).
The layer sometimes bleed into each other because its an inefficiant or complex to process them in order.
TLS(Transport Layer Security) its set up or configure in session layer but works in transport layer ,session layer ,presentaion layer and application layer
It is inefficient to process them in order. For eg, there are some devices that dealt with physical layer but now they use tranport and internet layer simultaneously to filter the data and route them quickly.
