Question 1
Suppose there are three routers between a source host and a destination host.
1. Over how many interfaces an IP datagram will travel from source to destination
host?
2. How many forwarding tables will be used?
Problem 1
(K:4-P12)
Rewrite the following forwarding table using the a.b.c.d/x notatation:
Prefix Match
Link Interface
11001000 00010111 00010
0
11001000 00010111 00011000
1
11001000 00010111 00011
2
Default
Problem 2
3
(K:4-P18)
Consider the following network setup depicting a private network…
126.13.89.67
Suppose that the ISP assigns the router the IP address 126.13.89.67 and that the network
address of the home network is 192.168/16.
1. Assign addresses to all interfaces in the home network
2. Suppose each host has to ongoing TCP connections, all to port 80 at host
128.119.40.86. Provide the six corresponding entries in the NAT translation table.
Problem 3
Consider sending a 3,000-byte datagram into a link that has an MTU of 500 bytes.
Suppose the original datagram is stamped with the identification number 422. How many
fragments are generated? What are the relevant fields in the header?
Problem 4
Consider the network shown below.
1. Show the operation of Dijkstra’s (Link State) algorithm for computing the least
cost path from E to all destinations. Also, explicitly list the shortest path routes
from E to all destinations that are the result of the algorithm’s computation.
2.
Show the distance table that would be computed by the distance vector algorithm
in B. Note: you do not have to run the distance vector algorithm; you should be
able to compute the table by inspection.
Problem 5
Consider a node Z, which has only two neighbors – X and Y. The link cost from Z to X
is 2 and the link cost from Z to Y is 3. Suppose X and Y have the distance tables shown
below, which they send to Z.
DX
s1
s2
s3
f
13
2
g
5
7
DY
t1
t2
4
f
6
5
8
9
g
2
9
7
…
t3
…
Complete the following table in node Z after it receives the distance tables from its
neighbors X and Y.
DZ
f
g
…
X
Y