Networking with the TCP/IP protocol
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Final Exam
Due: June 3
Take Home
Lap-Yan LEUNG
SECTION 1 Alphabet soup
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Under each of the following descriptions, write in the acronym and
what the acronym stands for. (2 pts each) Note some questions have more
than one correct answer.
1.1 A protocol that allows a node to obtain its own IP address
1.2 A world-wide hypermedia information retrieval initiative aiming
to give universal access to a large universe of documents
1.3 The name of the version of Unix that was developed at UC Berkeley
1.4 A program developed by Sun Microsystems that allows systems to
share disk drives with each other
1.5 A transport layer protocol of the TCP/IP suite that provides connection-oriented
reliable byte stream delivery service
1.6 A protocol that maps IP addresses to Ethernet MAC addresses
1.7 An internet layer protocol that handles messaging for error conditions
such as non-existent hosts.
1.8 A TCP/IP suite protocol for sending electronic mail or messages
1.9 This program, also known as YP or yellow pages, provides important
system administration information using a client/server arrangement
1.10 A "language" for writing text documents with embedded
links to other documents.
1.11 A protocol that allows routers and gateways to exchange routing
information
1.12 Working notes of the Internet research and development community
which document the proposed and/or established networking standards
1.13 A research agency of the DOD that established a packet-switching
network of computers that was later to become the Internet
1.14 A transport-layer connection-less datagram delivery service, part
of the TCP/IP protocol suite
1.15 The term used to describe an address or location on the World
Wide Web.
1.16 A protocol for delivering TCP/IP networking over serial lines
1.17 A protocol which attempts to reduce the number of routes which
must be advertised between domains on an internet by allowing flexible
address/netmask combinations outside of the traditional IP class structure.
1.18 A list of common questions and answers that is routinely posted
to an appropriate news group
1.19 A set of standards for communicating with devices (such as routers)
which are connected to a TCP/IP network for the purpose of monitoring or
controlling the network
1.20 A client/server protocol for distributing domain names and related
information
Bonus:
A field in the IP header which is decremented each time the packet
traverses a gateway, and which keeps the packet from being transferred
ad nauseum
SECTION 2 General
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2.1
Name 2 ways we've discussed to log in to a remote system.
Name 5 more application layer programs typically found in TCP/IP environments
that a person interacts with, and describe what each one is used for. Warning:
These must be interactive programs, not background programs.
- ftp - file transfer
- nslookup - Queries Internet name servers interactively
- rcp - copy files between remote systems
- rdump - remote files system dumps
- rsh - execute a command on remote system
Name 2 programs or protocols that are considered application layer
programs with which a person does not directly interact ("user-unaware"
programs). (9 pts)
- rlogind - The remote login server
- ftpd - The DARPA Internet File Transfer Protocol server
2.2
Name 5 network related Unix commands, and describe what they do. Do
not "reuse" any answers from question 2.1 regarding applications.
(5 pts)
- arp - Displays and controls Address Resolution Protocol (ARP) tables
- ifconfig - Configures or displays network interface parameters
- netstat - Displays network statistics
- ping - Sends ICMP ECHO_REQUEST packets to network hosts to check connectivity
- traceroute - print the route that packets take to the network host
2.3 You're starting a new TCP/IP network for a small organization that
wants to connect to the Internet. What steps do you take? (5 pts)
- 1. Discuss internally to decide what services are needed.
- 2. Discuss with Internet service providers - what services they can
provide and their costs.
- 3. Build network interface to connect to ISP interface.
2.4 Compare and contrast the characteristics of a server program versus
a client program. (3 pts)
- A server program provides service while a client program provides user
interface. A server program should run all the time. A client program usually
runs as user need. A client program communicates with it server program
to provide service to user.
2.5 What is the difference between a connection-oriented service and
a connection-less service? Name one of each from the TCP/IP suite. (5 pts)
- A connection-oriented service: establish connetion first, transfer
data packets in sequence, and provide error checking.
- A connection-less service: send data out as fast as possible, no matter
there is connection or not.
- Example: FTP and NFS
2.6 Why does the ftp protocol use two well known ports?
- One port is used for data transfer, another for process control.
2.7 DNS is used to map domain names to IP addresses.
- What other uses are there for DNS?
- DNS can preserve IP name. No matter how the IP address change the IP
name can always stay the same.
- The DNS can map many IP name to the same IP address, that allows many
registered user to share the same host and keep their own identities
- What is the purpose (or purposes) of the in-addr.arpa reverse domain?
(2 pts)
- It allows DNS to resolve IP addresses dynamically; therefore, DNS do
not have to remember that many IP names and addresses.
2.8 What is an alternative to using DNS? What are the advantages/ disadvantages
to using DNS? (2 pts)
- Using /etc/hosts file to keep all IP names and IP addresses. It is
faster than DNS because no network traffic needed before the destination
is found.
2.9 What are the 2 "types" of top level domain names? Name
3 of each & describe. (6 pts)
- Geographical:
- http://www.santa-barbara.ca.us - US domain
- http://www.liv.ac.uk - United Kingdom
- http://www.itea.unit.no - Norway
- Organizational:
- http://www.hp.com - Comercial
- http://www.ucsb.edu - Education
- http://www.whitehouse.gov - Goverment
2.10 What are the 3 types of DNS servers, and how do they differ? (6
pts)
- Flat namespace, Hierarchical names, Subset authority.
2.11 Describe encapsulation. In what layers does encapsulation occur?
(2 pts)
- In session and transport layers, put a complete session layer message
into a transport layer message.
2.12 For each of these IP addresses, determine what class it is in:
(5 pts)
- 126.13.142.249 - B
- 129.252.245.1 - B
- 199.1.1.1 - C
- 191.11.12.13 - B
- 223.19.155.4 - C
2.13 You have subnetted your class C network with the following subnet
mask: 255.255.255.240 How many useable subnets do you have, and what is
the maximum number of hosts on each? (2 pts)
- 4094 subnets, 14 hosts maximum on each.
2.14 Name the 7 layers of the OSI model (3 pts)
- physical, data-link, network, transport, session, presentation, and
application.
2.15 What is port multiplexing and why does it exist? What are the
5 pieces of information that uniquely identify a packet? (2 pts)
- Different applications use different ports. Their datagrams including
port information are encapsulated into network packet to transfer.
- Source address, destination address, source port, destination port,
and sequence number.
2.16 Describe how TCP establishes a connection from one host to another.
(2)
- Source sends SYN to destination. When destination received SYN, it
sends SYN+ACK to source. When source recieved SYN+ACK, it sends ACK. When
destination received ACK, the connection established.
2.17 Name 3 advantages of electronic mail over the US postal service.
(3 pts)
- Faster, lower cost, check mail remotely.
2.18 IP and UDP are both connectionless services. What does UDP provide
that IP doesn't? (1 pt)
2.19 TCP and UDP are both transport layer delivery services. What does
TCP provide that UDP doesn't? (1 pt)
- TCP gurantee the data transfer but UDP does not.
2.20 What does a name service resolver do? (1)
- Translate an IP name to an IP address
2.21 What is the purpose of "proxy arp" and how does it work?
(2)
- Let more multiple networks to share the same IP network address. The
route running proxy arp answers APR request on each network for hosts on
the other network, giving it MAC address and then routing datagrams when
they arrive.
2.22 What are 3 differences between IP addresses and MAC addresses?
(2)
- IP is logically defined while MAC is physically defined; therefore
IP is portable but MAC is not portable.
- MAC identifies the hardware's maker but IP cannot.
2.23 What is the purpose of a "default gateway"? (1)
- The interconnection point.
2.24 Within RIP, what does a "hop count" signify? (1)
- Number of routers between source and destination.
2.25 What is the purpose of "anonymous ftp"? (1)
- Provide public file access.
2.26 Let's assume you are using an email program on a computer that
is attached to an ethernet network, and on the network there is a router
that connects to the Internet. You've just composed a note to billg@microsoft.com
to let your friend know that you'd be happy to accept a donation from him
for a worthy cause. Describe what protocols and address mapping mechanisms
are involved between the time you press the "send" button and
the time when your network interface begins transmitting the first frame
that contains data. (3)
2.27 What are the minimal pieces of information that are typically
used to configure a node on a TCP/IP network? What is a protocol that allows
a node to automagically configured? (3)
- IP address, subnet mask, default gateway
- DHCP
2.28 What are some advantages/disadvantages TCP/IP networks versus
Novell networks? (3)
- IP packet has less overhead than IPX packet. IPX is easier to install
than IP network. IP is more portable; therefore, it is more favorble for
internetworking.
- IPX uses MAC address as part of the host address; therefore, it avoids
address duplication.