Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Solutions for Exam 2 - Computer Communications Networks - Fall 2002 | CS 742, Exams of Computer Science

Material Type: Exam; Class: Computer Comm Networks; Subject: Computer Science; University: Wichita State University; Term: Fall 2002;

Typology: Exams

Pre 2010

Uploaded on 08/17/2009

koofers-user-pry
koofers-user-pry 🇺🇸

10 documents

1 / 3

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
CS 742 Computer Communication Networks Exam 2 - Name:
Fall 2002
Part 1: (30 p oints - 3 points for each problem)
( C ) 1. IP is a (A) hardware (B) network architecture (C) protocol (D) software
( C ) 2. The package size of an ATM cell is:
(A) 32 bytes (B) 48 bytes (C) 53 bytes (D) 64 bytes
( A ) 3. Which command sends ICMP echo request packets to network hosts?
(A) ping (B) netstat (C) ifconfig (D) arp
( B ) 4. What is the header size of a IPv6 packet?
(A) 20 bytes (B) 40 bytes (C) 48 bytes (D) 60 bytes
( D ) 5. Which address is shown when we issue the command: ping localhost?
(A) the IP address of the machine (B) 0.0.0.0 (C) 127.0.0.0 (D) 127.0.0.1
( A ) 6. Which is a multicast address?
(A) 224.5.6.7 (B) 196.168.2.1 (C) 0.0.0.0 (D) 127.0.0.1
( D ) 7. Which byte order is used in the Internet protocols?
(A) forward-endian (B) reverse-endian (C) little-endian (D) big-endian
( C ) 8. Which I/O models is used in the select function?
(A) blocking I/O (B) nonblocking I/O (C) I/O multiplexing (D) signal driven I/O
( B ) 9. Which function is not used in UDP socket programming in C?
(A) bind (B) listen (C) socket (D) recvfrom
( A ) 10. In which function do we specify PF UNIX or PF INET?
(A) socket (B) bind (C) connect (D) listen
Part 2: (70 p oints + 10 bonus points)
1. Briefly explain these terminologies. If they are acronyms, also write what they stand for. (12 points)
(a) RIP - Routing Information Protocol is a widely-used protocol for managing router information
within a self-contained network such as a corporate local area network or an interconnected group
of such LANs.
(b) DHCP - Dynamic Host Configuration Protocol is a communications protocol that lets network
administrators manage centrally and automate the assignment of Internet Protocol (IP) addresses
in an organization’s network.
(c) CIDR - Classless Inter-Domain Routing or supernetting is a way to allocate and specify the
Internet addresses used in inter-domain routing more flexibly than with the original system of
Internet Protocol IP address classes.
(d) BGP - Border Gateway Protocol is a protocol for exchanging routing information between gate-
way hosts (each with its own router) in a network of autonomous systems.
2. A 1500-byte datagram (20-byte IP header plus 1480 bytes of data) arrives for transmission across a
network that has the maximum transmission unit (MTU) of 600 bytes. How long will each of the three
segments be (including the IP header)? (4 points)
Ans: The largest amount of data that can be transmitted is 600 - 20 = 580 bytes. The last seg-
ment will be 1480 - 580 -580 = 320 bytes. The three segements will be 600 bytes, 600 bytes, and 340
bytes.
pf3

Partial preview of the text

Download Solutions for Exam 2 - Computer Communications Networks - Fall 2002 | CS 742 and more Exams Computer Science in PDF only on Docsity!

CS 742 Computer Communication Networks Exam 2 - Name: Fall 2002

Part 1: (30 points - 3 points for each problem)

( C ) 1. IP is a (A) hardware (B) network architecture (C) protocol (D) software

( C ) 2. The package size of an ATM cell is: (A) 32 bytes (B) 48 bytes (C) 53 bytes (D) 64 bytes

( A ) 3. Which command sends ICMP echo request packets to network hosts? (A) ping (B) netstat (C) ifconfig (D) arp

( B ) 4. What is the header size of a IPv6 packet? (A) 20 bytes (B) 40 bytes (C) 48 bytes (D) 60 bytes

( D ) 5. Which address is shown when we issue the command: ping localhost? (A) the IP address of the machine (B) 0.0.0.0 (C) 127.0.0.0 (D) 127.0.0.

( A ) 6. Which is a multicast address? (A) 224.5.6.7 (B) 196.168.2.1 (C) 0.0.0.0 (D) 127.0.0.

( D ) 7. Which byte order is used in the Internet protocols? (A) forward-endian (B) reverse-endian (C) little-endian (D) big-endian

( C ) 8. Which I/O models is used in the select function? (A) blocking I/O (B) nonblocking I/O (C) I/O multiplexing (D) signal driven I/O

( B ) 9. Which function is not used in UDP socket programming in C? (A) bind (B) listen (C) socket (D) recvfrom

( A ) 10. In which function do we specify PF UNIX or PF INET? (A) socket (B) bind (C) connect (D) listen

Part 2: (70 points + 10 bonus points)

  1. Briefly explain these terminologies. If they are acronyms, also write what they stand for. (12 points)

(a) RIP - Routing Information Protocol is a widely-used protocol for managing router information within a self-contained network such as a corporate local area network or an interconnected group of such LANs. (b) DHCP - Dynamic Host Configuration Protocol is a communications protocol that lets network administrators manage centrally and automate the assignment of Internet Protocol (IP) addresses in an organization’s network. (c) CIDR - Classless Inter-Domain Routing or supernetting is a way to allocate and specify the Internet addresses used in inter-domain routing more flexibly than with the original system of Internet Protocol IP address classes. (d) BGP - Border Gateway Protocol is a protocol for exchanging routing information between gate- way hosts (each with its own router) in a network of autonomous systems.

  1. A 1500-byte datagram (20-byte IP header plus 1480 bytes of data) arrives for transmission across a network that has the maximum transmission unit (MTU) of 600 bytes. How long will each of the three segments be (including the IP header)? (4 points)

Ans: The largest amount of data that can be transmitted is 600 - 20 = 580 bytes. The last seg- ment will be 1480 - 580 -580 = 320 bytes. The three segements will be 600 bytes, 600 bytes, and 340 bytes.

  1. How could the ARP protocol be used to determine if another host on my network is using my IP address? (4 points)

Ans: Send an ARP broadcast with my IP address. If another host responds, we have identified a host using my IP address. Recall that only the owner of an IP address should respond.

  1. True or False questions. If it is false, explain why? (9 points)

(a) An ICMP Echo Request and Reply can be used to determine if we have connectivity between a client and server at the Application Layer? (b) Each host computer or router can only be assigned one Internet (IP) address. (c) Only the owner of a given IP address should respond to an ARP request.

Ans:

(a) False, at best it can be used if we have connectivity at the Network Layer because ICMP is a Network Layer Protocol. (b) False, a host with two ethernet cards should have two IP addresses, also routers always have multiple IP addresses assigned. (c) True.

  1. What is the purpose of the ATM Adaptation Layer (AAL)? What is its convergence sublayers (CS)? (5 points)

Ans:

(a) Higher layer messages need to be fragmented to the ATM cell. The ATM Adpatation Layer sits between ATM and the variable-length packet protocols to handle fragmentation and reassembly. (b) Covergence sublayers in AAL are used to support various service in the higher layer including voice, video, and data.

  1. An organization has a class C network 192.168.1.0 and wants to form subnets for 3 departments, with hosts as follows: A 72 hosts B 60 hosts C 40 hosts

There are 172 hosts in all. Give a possible arrangement of network and subnet masks to make this possible. (9 points)

Ans: Department Network Netmask IP Addresses A 192.168.1.0/25 255.255.255.128 128 B 192.168.1.128/26 255.255.255.192 64 C 192.168.1.192/26 255.255.255.192 64

  1. Suppose a router has built up the routing table as shown in the following table. The router can deliver packets directly over interfaces eth0 and eth1, or it can forward packets to other routers in the table.

Destination Netmask Gateway 156.26.10.0 255.255.255.192 eth 156.26.10.128 255.255.255.192 eth 156.26.0.0 255.255.0.0 156.26.10. 0.0.0.0 0.0.0.0 156.10.1.

Describe what the router does with a packet addressed to each of the following destinations: (8 points)

(a) 156.26.10.41 - deliver packets directly through eth