CENG 362 - Homework 2
Due date: May 12th Monday 23:55
What to hand in: Upload your homework to Moodle. Remember, cheating will
not be tolerated and you will receive no marks for the whole assignment. Any
answer without explanation will receive no marks as well.
Question 1 (15points):
ISP A owns the block of addresses of the form 161.32.18.64/26. Suppose it wants to
create 16 subnets from this block, with each block having the same number of IP
addresses. What are the prefixes (of form a.b.c.d/x) for the 8 subnets? Explain how
you formed the addresses.
Question 2 (10points):
Consider sending a 3000-byte datagram on a link with an MTU of 512 bytes. If the
original identification number of the datagram is 350, how many fragments are
generated? What are the values of the fields related to fragmentation in the datagram
headers? Explain how you formed the datagrams.
Question 3 (10points):
Compare and contrast the techniques used to overcome the NAT traversal problem?
Question 4 (25 points):
Use Dijkstra’s shortest path algorithm, to calculate the shortest path from node B to
every other node.
a) Complete the following table.
N’ D(A),p(A) D(C),p(C) D(D),p(D) D(E),p(E) D(F),p(F)
b) Draw the spanning tree. From these results, show the least cost path from B to
F, and briefly describe (in a sentence) how you got that answer from your
work in part a).
c) Draw the forwarding table of B in (Destination, Link ) pair format for each
destination.
Question 5(25 points):
Apply the distance vector algorithm until all of the nodes reach the stable state.
Assume all nodes exchange distance vectors synchronously, show the distance
vector tables and explain how you got the values.
Question 6 (15 points):
Consider the following network. Suppose AS11 is running OSPF as their intraAS routing protocol while AS37 is running RIP and AS19 is running IS-IS
protocol. Suppose eBGP and iBGP are running as inter-AS routing protocol.
37a,11a,11d and 19a are gateway routers
11b
11a
11c
AS11
11d
11e
37a
37b
19a
AS19
AS37
19b
19c
X
a)
b)
c)
d)
Router 37b learns about prefix x from which routing protocol: RIP,
OSPF,IS-IS, eBGP or iBGP? Explain.
Router 19c learns about x from which routing protocol? Explain.
Router 11d learns about x from which routing protocol? Explain.
Router 11e learns about x from which routing protocol? Explain.
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