Computer Networks Answers

Two adjacent nodes P and Q use Go-Back-N sliding window protocol with 3-bit 

sequence numbers and a send window size of 7. What is the window position for P 

and Q by drawing the sequence diagram after :

 P sends all seven frames 0,1,2,3,4,5and 7 frames in the current window. Frame 

5 is lost.

 Q acknowledges frames 0,1,2,3,4, all the acks are received by P except for ack 

2 and ack 3.

 Two adjacent nodes A and B use the Go-Back-N sliding window protocol with 5-bit 

sequence numbers and a send window size of 10. We assume that A is transmitting to

B. What is the window position for A and B by drawing the sequence diagram after :

 A sends frames 0,1,2,3,4,5,6,7,8, frames 5 and 8 are lost.

 B acknowledges frames 0,1,2,3 and 4,the acks for 1 and 3 are lost

 The acks for 0,2,4 are received by A.

Ann, an accountant, reports that after turning on her new laptop, she received a message stating her IP address is already in use on the system. She tried going back to her old desktop, which she now only uses for email, but received the same message. As a Network expert, you checked the account and sees a comment that Ann requires a special network setup to connect to the banking software.

Explain what could be the cause of the message received by Ann, and how you would resolve the issue as a Network expert. Also, what “special network set-up” is required to connect to the Banking software.

A technician is setting up a new wireless network at a branch office that previously had only wired connectivity with statically assigned IP addresses. After setting up the network, the technician configures a server to provide IP addresses to wireless clients. During testing, the technician is unable to access the Internet or named network resources. The technician receives a valid IP address from the DHCP server and can ping the default gateway.

Explain various steps that can be taken to resolve this issue. (each step highlighted MUST be accompanied by the intended solution the step hopes to achieve)

1. Network configurations

1. Receive internet access from the WAN

2. Provide internet access to devices connecting to AP that is connected to the ubuntu

server

3. Block/Allow IP/MAC address

2. Configurations can be altered/configured programmatically

1. SSID of the external AP

2. Can be password protected or Open Security

3. Network interfaces so we can choose what will be the LAN and the WAN

4. Set DHCP configuration for the clients that will be connecting to the LAN (ex. IP pool

range)

A firewall is Network security device that monitors incoming and outgoing network traffic as well

as permits or blocks data packets based on a set of security rules”.

Critically discuss how a firewall operates and the various types of firewalls (Use appropriate

diagram to corroborate your discussion)

Explain why devices on a network need addresses