1b

2c

3c

4b

5a

6b

7a

8d

9b

10

11a

12a

13a

14b

15a

16c

17a

18a

19d

20a

21b

http://vnpro.org/forum/showthread.php/714-Routing-Protocol-ho%E1%BA%A1t-%C4%91%E1%BB%99ng-%E1%BB%9F-t%E1%BA%A7ng-m%E1%BA%A5y-trong-m%C3%B4-h%C3%ACnh-OSI/page2

22b

23

24

25

26

27a

28b

29

30a