COIT20261 Network Routing and Switching Assignment - Term 2, 2019

This document presents a comprehensive solution to a network routing assignment, addressing key concepts in networking. The assignment includes detailed routing tables for routers R1 and R4, showcasing network address, mask, next-hop address, and interface configurations. It explores subnetting techniques, explaining how different masks are applied to determine network addresses. The document also delves into congestion control methods, differentiating between open-loop and closed-loop approaches, and comparing TCP and BBR protocols, highlighting their respective strengths and weaknesses in managing network congestion and packet loss. The assignment also discusses the challenges of adopting new network protocols and analyzes the factors that influence the acceptance and implementation of new technologies in the field of networking.

Questions
Question 1: (10 marks)
Answer: Routing table of router R1:
Mask Network address Next-hop address Interface
/24 200.11.60.0 ------- M1
/24 220.10.40.0 150.3.0.3 M0
/22 140.21.0.0 ------- M2
/18 161.22.0.0 150.3.0.3 M0
/18 150.32.0.0 150.32.0.1 M0
/16 150.3.0.0 150.3.0.3 M0
/16 150.3.0.0 150.3.0.1 M0
/16 150.3.0.0 150.3.0.4 M0
Default Default 150.3.0.4 M0
(Lammle, 2016)
Routing table of router R4:
Mask Network address Next-hop address Interface
/24 200.11.60.0 150.3.0.2 M0
/24 220.10.40.0 -------- M1
/22 140.21.0.0 150.3.0.2 M0
/18 161.22.0.0 -------- M2
/18 150.32.0.0 150.3.0.1 M0
/16 150.3.0.0 150.3.0.2 M0
/16 150.3.0.0 150.3.0.4 M0
/16 150.3.0.0 150.3.0.1 M0
Default Default 150.3.0.4 M0
(Bee, 2017)
Question 2: (5 marks)
a)
A classes addressing is a technique of subnetting where the network divisions have uneven
subnet masks. In this technique, four columns are deployed to determine address of the network.
A router applies a subnet mask on the network address to determine whether the network exists
in its routing table. This is done in combination with the existing networks available. In case the
network address will find its tie to network in its table then the next node-address and the address
interface are delivered to the ARP table. If the network does not find its match, the network
packets are progressed to default network. (Carthern, et al., 2015)

b)
Mask Network address Next-hop address Interface
/24 220.11.60.0 150.3.0.2 M0
/24 220.10.40.0 150.3.0.3 M0
/22 140.21.0.0 150.3.0.2 M0
/18 150.32.0.0 ------- M1
/18 161.22.0.0 150.3.0.3 M0
/16 150.3.0.0 150.3.0.3 M0
/16 150.3.0.0 150.3.0.4 M0
/16 150.3.0.0 150.3.0.2 M0
Default Default 150.3.0.4 M0
Routing procedures events are taken as below,
- First mask of (/24) is applied on the network address. This will give us 150.32.0.0. This
network does not find a tie to our matching address.
- Second mask of (/22) is applied on our address. The outcome is 150.32.0.0. This network
does not tie to our matching address.
- Third mask (/18) is applied on our provided address, outcome is 150.32.0.0. The result ties
with the corresponding network address. Next node address and interface number are
forwarded to ARP.
c)
Table in section (b) above is deployed here, the steps are as below;
- First mask (/24) is applied on the allotted network address. Outcome is 150.32.48.0. The
outcome does not tie the respective network address.
- Second mask /22 is applied on our allocated network. Outcome (150.32.48.0) does not tie
with the corresponding network address.
- Third mask /18 is applied on our allotted network address. Outcome (150.32.0.0) ties with
the corresponding network address. Next hop interface number and address are forwarded to
ARP table.
Question 3: (10 marks)
1)
Congestion control methods as discussed by Behrouz are the open-loop congestion control and
the closed loop congestion control. In the open-loop congestion control, rules are applied to
hinder overcrowding before it happens. These policies are window policy, acknowledgement

policy and discarding policy. On the other hand, a closed loop congestion control method is
deployed to alleviate overcrowding once it take place. Methods and protocols used to achieve
this include choke packet technique, implicit signalling, back pressure and explicit signalling
(Behrouz, 2007).
2)
a. The current TCP congestion control takes the action of slowing down after it detects packet
loss. This is too late.
b. The TCP congestion controls are not compatible with other transport protocol. It should be
noted that TCP congestion control techniques are only apply to TCP protocol leaving UDP to
suffer the congestions.
3)
a. The TCP control techniques are designed to control packet losses whereas BBR protocol
responds to the actual congestion.
b. The BBR is concerned with improvement of network performance where the network is not
good, whereas TCP seeks to restore the packet loss.
c. In TCP deployment, explicit client is required whereas explicit client is not required in the
implementation of BBR
4)
In my own view, it not easy to get a new protocol accepted over the existing protocol standard
due to the following reasons;
- The present protocol (ie TCP) has been existent and has been working and it is still working,
therefore, to displace it one must appropriately cite the disadvantages of the existing protocol
and the advantages of the new protocol
- The present software and hardware is designed to suite TCP protocol based on
communication, therefore, introduction of a new protocol may be required to fit into both the
existing software and hardware which is difficult or the software and hardware must be
replaced worldwide, this so cost full. Hence, it is very difficult to replace an existing standard
protocol with a new protocol.
References
Bee, Y. H., 2017. Routing Technologies. 2nd ed. Kuala Lumpur: Open University Malaysia.

Behrouz, F., 2007. Data Communications and Networking. 4th ed. Boston Burr Ridge: McGraw-Hill.
Carthern, C., Wilson, . & Rivera, ., 2015. Cisco Networks: Engineers' Handbook of Routing, Switching, and
Security. 5th ed. New York City: Apress.
Lammle, T., 2016. CCNA Routing and Switching Complete Study Guide. 4th ed. Hoboken: John Wiley &
Sons.