Need of Protocol Layering :
- Networks can be very complex. To reduce the design complexity, most networks are designed as a stack of layers
- It provides modularity (independent layers) which helps in easy maintenance and updation of the system.
- It allows us to separate the services from the implementation.
- Communication does not always use only two ends sytems, They are intermediate system that need only some layer but not all the layers. If we do not use protocol layering, we would have to make each intermediate system complex on the end system, which makes whole system more expensive