The document discusses the network layer and design principles for the Internet. It covers a lecture on chapter 5 of the network layer. The design principles for the Internet emphasize making sure the network works, keeping it simple, making clear choices, exploiting modularity, expecting heterogeneity, avoiding static options and parameters, looking for a good but not necessarily perfect design, being strict when sending but tolerant when receiving, considering scalability and performance/cost.

1. DATA COMMUNICATION
AND
NETWORKING
Prof. MAHESH HASANI
1
ENGINEERING FUNDA
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a
Engineering Funda Android APP Engineering Funda YT Channel

2. LECTURE-21
CHAPTER-5
NETWORK LAYER
2
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a
Engineering Funda Android APP Engineering Funda YT Channel

3. 3
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a
Engineering Funda Android APP Engineering Funda YT Channel

4. 4
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

5. 5
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

6. 6
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

7. 7
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

8. 8
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

9. 9
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

10. 10
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

11. 11
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

12. 12
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

13. 13
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

14. 14
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

15. 15
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

16. 16
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

17. 17
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

18. 18
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

19. 19
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

20. 20
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

21. 21
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a

22. DESIGN PRINCIPLES FOR INTERNET
1. Make sure it works.
2. Keep it simple.
3. Make clear choices.
4. Exploit modularity.
5. Expect heterogeneity.
6. Avoid static options and parameters.
7. Look for a good design; it need not be perfect.
8. Be strict when sending and tolerant when
receiving.
9. Think about scalability.
10.Consider performance and cost. 22
E
n
g
i
n
e
e
r
i
n
g
F
u
n
d
a
Engineering Funda Android APP Engineering Funda YT Channel