Chapter 4-5 - Part1

Question 1

Difference between End systems and routers?

Answer 1

End systems have the full stack layers (app, transport, network, link, physical)

Routers only have network, link and physical

Question 2

Forwarding vs Routing

Answer 2

Forwarding: moving packets to appropriate output link (DATA PLANE: per-router function)

Routing: determining the route taken from source to dest (CONTROL PLANE: network wide logic)

Question 3

Control vs Data Plane

Answer 3

Data: destination-based forwarding

Control: individual routing algorithm in each router interact with each other routers

Data plane decided by control plane.

Question 4

What does it mean internet is a “best effort” service model

Answer 4

No guarantees on:
- successful delivery

• timing/order
• bandwidth available

Pushes complexity to the end systems instead.

Question 5

IP Datagram Format (Important sections)

Answer 5

1. TTL: remaining max hops, decremented at each router
2. Overhead: 20 bytes of TCP + 20 bytes of IP