COIT20261 Term 1 2019 Network Routing and Switching Assignment

This document presents a comprehensive solution to the COIT20261 Network Routing and Switching assignment. The solution includes detailed routing tables for routers R2 and R3, illustrating the mask, network address, next-hop address, and interface for each entry. The assignment addresses classless addressing, explaining how routers handle packet forwarding based on network addresses and masks. It also covers packet forwarding calculations, demonstrating how routers like R4 and R3 process destination addresses using masks to determine the next hop. Furthermore, the solution delves into inter-domain and intra-domain routing concepts, explaining the role of Autonomous Systems (AS) in BGP, and comparing and contrasting inter-domain and intra-domain protocols (BGP and OSPF). It highlights the differences in their implementation, structure, and routing mechanisms. Finally, the solution explains the reasons for using different protocols in inter-domain and intra-domain routing, emphasizing the scalability and functionality differences between them, providing a complete understanding of the assignment's requirements and solutions.

COIT20261 Network Routing and Switching Term 1, 2019
Assignment item —Written Assessment-2
ANSWER TEMPLATE ASSIGNMENT TWO
Type your answers in the spaces provided
Marking criteria:
First Name:_________________________ Last Name:____________________________
Student ID: __________________________
Questions Mark
allocated
Mark
earned
Question 1: (10 marks) 5 each
table
Answer: Routing table of router R2:
Mask Network address Next-hop address Interface
255.255.255.0 200.11.60.0 140.21.0.1 /22 M1
255.255.255.0 200.11.60.0 150.3.0.2 /16 M1
255.255.252.0 140.21.0.0 150.3.0.2 /16 M2
255.255.252.0 140.21.0.0 200.11.60.1 /24 M2
255.255.0.0 150.3.0.0 140.21.0.1 /22 M0
255.255.0.0 150.3.0.0 200.11.60.1 /24 M0
255.255.255.0 200.11.60.0 140.21.0.1 /22 M1
The above routing table, shows each router interface, which has the mask, the
network address, and their next hope in the network (Kim and Ryu, LG
Electronics, 2010). Example for interface M1 its cover is 255.255.255.0 since
its /24, and the network address is 200.11.60.0. The interface has two hope
addresses 140.21.0.1 /22 and 150.3.0.2 /16.
The routing table of router R3:
Mask Network address Next-hop address Interface
255.255.192.0 161.22.0.0 150.3.0.3 /16 M2
5 max
5 max

COIT20261 Network Routing and Switching Term 1, 2019
Assignment item —Written Assessment-2
255.255.192.0 161.22.0.0 220. 10.40.1 /24 M2
255.255.0.0 150.3.0.0 161.22.0.1 /18 M0
255.255.0.0 150.3.0.0 220.10.40.1 /24 M0
255.255.255.0 220.10.40.0 150.3.0.3 /16 M1
255.255.255.0 220.10.40.0 161.22.0.1 /18 M1
255.255.192.0 161.22.0.0 150.3.0.3 /16 M2
Question 2: (5 marks)
a) When a router uses a classless addressing the whole address, space will be
divided into manageable blocks. If a packet is sent with a network address
between 161.22.0.0 to 16.22.0.192 to a specific final destination, the packet will
be sent to the next router first which checks whether the address is in its network.
If the address is not in the network, the packets will be sent to the next router
which checks whether the address is in the network and if not, it will be
forwarded until the packet reach the destination.
1 max
b) When a packet with destination address 150.32.0.17 arrive at R4, the following
calculations will be performed by the router to forward the packet (Shiota, NEC,
2016).
i. The mask (/16) is assigned to the destination address, and the
outcome is 150.32.0.0 which doesn’t match to the corresponding
network address.
ii. The mask (/18) is also applied to the destination address, and the
outcome is 150.32.0.0, and it matches to the same network
address. the next hope address and the interface number M1 are
forwarded to ARP for processing.
2 max
c) When the packet having destination address, 150.32.48.15 arrives at R3 a router
performs the following steps.
i. The mask (/18) is assigned to the destination address, and the
outcome is 150.32.48.0 which doesn’t match to the
corresponding network address.
ii. The second mask (/24) is also assigned to the destination address,
2 max

COIT20261 Network Routing and Switching Term 1, 2019
Assignment item —Written Assessment-2
and the outcome is 150.32.48.0 which doesn’t match to the
corresponding network address.
iii. The third mask (/16) is then assigned to the destination address,
and the outcome is 150.32.48.0 which doesn’t match to the
corresponding network address.
Since all masks on the router do not match the destination network, ARP will be
given next hope address 150.3.0.3 and the interface M0 since the packet needs to
be sent to other networks.
Question 3: (10 marks)
a) Autonomous systems and their relation to BGP
AS is an element of router rule for one network that is managed by a network
administrator or network operators on behalf of a single administrative unit like
business enterprise, university. It is a mutual routing domain that defines clearly
routing policy to the internet in the organization (Shue, Kalafut, and Gupta,
2012). It has a globally unique number which ranges from 1 to 64511. Examples
of the autonomous system are single-homed stub autonomous system and a
multi-homed stub autonomous system. The BGP enables the domain systems to
exchange routing data with other domain systems.
1 max
b) Inter-domain protocol is a routing procedure that ha been put in place amongst
two or more different networks. It focuses on getting to different domains in the
networks. The main interdomain protocol is the Border gateway protocol, which
allows exchange or transfer of information between domains in different
locations. The routing in interdomain occurs amongst the autonomous networks,
and the routing procedure ignores that the internet comprises the group of the
interconnected autonomous system.
Two max
c) Intradomain routing is a routing setup within individuals' network. It focuses on
reaching devices that are contained in the same domain. The routing rules found
in intradomain routing are; OSPF, RIP, EIGRP and focuses on assigning routes
Two max

COIT20261 Network Routing and Switching Term 1, 2019
Assignment item —Written Assessment-2
on the network and through this, the router will know exact routes of the subnets.
The intradomain routing occurs in an autonomous network, and its protocols
overlook the internet exterior the autonomous system (Labovitz, Iekel-Johnson,
McPherson, Oberheide, & Jahanian,2011).
d) differences and similarities between interdomain protocol and intra-domain
protocol.
The examples of interdomain and intradomain protocols are BGP and OSPF,
respectively.
The significant similarity between the BGP and OSPF is that the two protocols
are used to transmit information from one destination to the other in the network.
There are also differences between the BGP and OSPF. These include:
i. The implementation of OSPF is more straightforward compared to the
implementation of BGP.
ii. The structure of the OSPF is hierarchical while the structure of BGP
mesh.
iii. The routing protocol in OSPF occurs inside the autonomous system
since it’s an interior gateway routing protocol while in BGP routing
protocol occurs between two domain since it is an exterior gateway
routing protocol.
iv. There are more scalability and flexibility in BGP compared to OSPF,
and also it is used in a more extensive network, unlike OSPF.
v. BGP uses Path vector routing while in OSPF link state routing is
used.
3 max
e) The reason why protocols are different on inter-domain and intra-domain
routing.
The reason for different protocols is that intra-domain protocols were meant for
sharing information within a small network as it computes the shortest path in the
network and allows devices reach one another within the same domain while for
2 max

COIT20261 Network Routing and Switching Term 1, 2019
Assignment item —Written Assessment-2
the inter-domain protocols the will enable the communication between different
domains and is used in large scale.
Total marks awarded 25 (max)
Less late penalties
Less plagiarism penalties
Total marks earned
Markers comments:
Conclusion
In conclusion, the routing protocols in the network both interior and exterior gateway
protocols enable the transfer of information in the network. The interior gateway protocol
ensures that the device reaches to one another in the same autonomous system, and the
exterior gateway protocol ensures that one autonomous system reaches another in another
network. This allows the overall transfer of information in the network.

COIT20261 Network Routing and Switching Term 1, 2019
Assignment item —Written Assessment-2
References
Kim, Y.H. and Ryu, K.S., LG Electronics Inc, 2010. IP addressing to support IPv4 and IPv6.
U.S. Patent 7,801,078.
Labovitz, C., Iekel-Johnson, S., McPherson, D., Oberheide, J., & Jahanian, F. (2011). Internet
inter-domain traffic. ACM SIGCOMM Computer Communication Review, 41(4), 75-
86.
Shiota, Y., NEC Corp, 2016. Packet exchange and router and input packet processing
method thereof. U.S. Patent 6,987,762.
Shue, C.A., Kalafut, A.J., and Gupta, M., 2012. Abnormally malicious autonomous systems
and their internet connectivity. IEEE/ACM Transactions on Networking (TON), 20(1),
pp.220-230.