1. Router XYZ has forwarding table: Network/Mask Next_Hop 94.212.192.0/20 delive
ID: 3689102 • Letter: 1
Question
1. Router XYZ has forwarding table:
Network/Mask
Next_Hop
94.212.192.0/20
deliver directly
94.212.208.0/20
10.0.0.1
94.212.224.0/19
20.0.0.2
94.212.192.0/18
30.0.0.3
0.0.0.0/0
40.0.0.4
Explain what router XYZ will do with packets with the following destination addresses. Make sure to use longest prefix routing.
a. 94.212.193.15
b. 94.212.204.2
c. 94.212.210.10
d. 94.212.185.10
e. 30.0.0.3
f. 94.212.196.12
g. 94.212.191.11
h. 94.212.192.255
i. 94.210.224.20
j. 94.212.226.250
Network/Mask
Next_Hop
94.212.192.0/20
deliver directly
94.212.208.0/20
10.0.0.1
94.212.224.0/19
20.0.0.2
94.212.192.0/18
30.0.0.3
0.0.0.0/0
40.0.0.4
Explanation / Answer
In all of the following examples I am converting after 16th from left side i.e. 94.212._._
I have separated the network address from host address by space.
94.212.192.0/20 deliver directly
1100 0000
94.212.208.0/20 10.0.0.1
1101 0000
94.212.224.0/19 20.0.0.2
111 00000
94.212.192.0/18 30.0.0.3
11 000000
0.0.0.0/0 40.0.0.4
If any of the packet does not matches with above 4 then it will be forwarded to 40.0.0.4
Now coming to the question:
94.212.193.15
11000001 matches with 11 and 1100. We go by maximum prefix match 1100 is bigger than 11
hence packet will be deliver directly
94.212.204.2
11001100 matches with 11 and 1100. We go by maximum prefix match 1100 is bigger than 11
hence packet will be deliver directly
94.212.210.10
11010010 matches with 11 and 1101 but 1101 is bigger than 11
hence packet will be forwarded to 10.0.0.1
94.212.185.10
10111001 matches with 0.0.0.0 only hence it will be forwarded to 40.0.0.4
30.0.0.3
matches with 0.0.0.0 only hence it will be forwarded to 40.0.0.4
94.212.196.12
11000100 matches with 11 and 1100. We go by maximum prefix match 1100 is bigger than 11
hence packet will be deliver directly
94.212.191.11
10111111 matches with 0.0.0.0 only hence it will be forwarded to 40.0.0.4
94.212.192.255
11000000 matches with 11 and 1100. We go by maximum prefix match 1100 is bigger than 11
hence packet will be deliver directly
94.210.224.20
matches with 0.0.0.0 only hence it will be forwarded to 40.0.0.4
94.212.226.250
11100010 matches with 111 hence it will be forwarded to 20.0.0.2
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.