A Network Programming Lecture by Steven Choy
Lecture Overview: We use a few meetings for course revision and tutorial. We review and discuss the main topics you have learned in the course.
Final Examination
- April 28, 2010, 09:30-12:30
- 3-hours, closed-book, written examination
- Part A - 10 short questions, all compulsory, amount to 40 marks
- Part B - 5 long questions, answer 3 out of 5 questions, amount to 60 marks
3 hours, 100 marks
180 minutes, 100 marks
1.8 minutes per mark
~70 minutes to answer all short question (40 marks)
~35 minutes to answer one long question (20 marks)
- You can bring calculator.
- Do not bring dictionary.
Scope of Examination
- Networking and Network Protocols
- Network Programming - Socket Programming
- Network programming - Higher Level and Other Topics
- Web Services and XML
- Network Design and Security
Networking and Network Protocols
Main lectures covering:
Some key questions and topics:
- Networking Stacks and Layers - Can you name each layers from top to bottom with appropriate examples?
- IP (Internet Protocol) suites, the five layers model - Can you name each of them with appropriate examples?
- What are the main functions of IP Protocol (in the network layer)?
- IPv4 (IP version 4) addressing and classes (Class A to E)
- Basic concepts of IP subnetting
- Can you explain/discuss the benefits of subnetting?
- Ability to organize your resources within a network.
- Ability to secure your resources by placing them into separate subnetworks
- speedup your network
- reduces network congestion by redirecting traffic and reducing broadcasts; it can significantly improve the performance of Ethernet network;
- makes it easier to control the network segment by dividing hosts into different subnetworks.
- What are the major functions of TCP?
- When should we use UDP rather than TCP?
- Can you explain the main limitations of IPv4?
- Can you explain the improvements made by IPv6?
- Two types of HTTP messages
- What are HTTP Headers?
- Can you illustrate the HTTP request structure?
- Can you illustrate the HTTP response structure?
- Can you explain the difference between HTTP GET method and HTTP POST method?
- What are FQDN and PQDN? Can you give appropriate examples?
- What is the difference between a primary and secondary DNS server?
- What is the difference between a domain and a zone in DNS?
Network Programming - Socket programming
Main lectures covering:
Some key questions and topics:
- What are sockets in network programming?
- Class Socket and ServerSocket in Java
- General operations of building a TCP client program in Java
- General operation of building a TCP server program in Java
- Can you write Java code for implementing a simple TCP client and server?
- 8 basic classes for Java network programming: InetAddress, Socket, ServerSocket, DatagramSocket, MulticastSocket, DatagramPacket, InputStream, OutputStream. Which classes are necessary in building TCP client, TCP server, UDP client, UDP server?
- Discuss the differences between using datagram (UDP) sockets and stream (TCP) sockets in programming client-server applications.
- Three situations of using UDP rather than TCP.
- Write Java code for implementing a simple datagram client and server.
- Write Java code for implementing a simple multicast client and server.
- Importance and limitations of multicast networking.
Network Programming - Higher level and other topics
Main lectures covering:
Some key questions and topics:
- Two main classes in Java URL framework: URL and URLConnection.
- What is the difference between a URL instance and URLConnection instance?
A URL instance represents the location of a resource. A URLConnection instance represents a link for accessing or communicating with the resource at that location.
The URLConnection represents a connection to the resource specified by the URL. It provides support for both well known protocols (e.g. HTTP, FTP) and custom ones.
- What are the benefits of using Java URL-related classes and interfaces rather than sockets and streams in building network applications?
- What are the functions of
bind and connect system calls in network programming in C?
- What are the functions of
listen and accept system calls in network programming in C?
- What are the functions of
send, sendto, recv, and recvfrom system calls in network programming in C?
- TCP Socket programming flow in C
- UDP Socket programming flow in C
- What is Remote Procedure Call (RPC)?
- Can you illustrate the RPC mechanism and architecture?
- What are the functions of client procedure stub and server procedure stub?
- What is the function of rpcgen in Sun RPC?
- What is XDR (External Data Representation) in the context of RPC?
- What are the advantages and disadvantages of using RPC over socket programming in building network applications?
- Advantages: The programmer can define a much cleaner, higher-level application protocol. All communication details are taken care of transparently.
- Disadvantages: RPC incurs computation and communication overheads in procedure calls setup. RPC provides less control on the data being transmitted across the network.
Web Services and XML
Main lectures covering:
Some key questions and topics:
- What is Web Services? Can you briefly describe the term in a few sentences?
- Can you illustrate the Web Services architecture?
- Can you explain the terms SOAP, WSDL, UDDI?
- What is the function of XML in implementing Web Services?
- What is the function of HTTP in implementing Web Services?
- Common encoding formats of response messages of Web services
- What is SOA (Service Oriented Architecture)?
- Three different styles (or realizations) of Web services?
- This is a old definition of Web services: a Web service is any piece of software that makes itself available over the Internet and uses a standardized XML messaging system. Discuss the validity of this definition in today's implementations of Web Services.
- What do we mean by a well-formed XML?
- What do we mean by a valid XML document?
- Can you list main properties of well-formed XML?
- Can you describe properties of valid XML?
- Document type definition (DTD)
- XML Schema Definition (XSD)
- Compare DTD and XSD.
- Why XML Schemas (or XSD) are more popular than DTD in defining the legal elements of an XML document?
Network Design and Security
Main lectures covering:
Some key questions and topics:
- Can you illustrate the NFS Architecture?
- What do we mean by access transparency in network file systems?
- What is the function of VFS (Virtual File System) in Unix/Linux machine?
- What is SMB (Server Message Block)?
- What is Samba?
- What is the difference between NFS and CIFS?
- What to do if we want share files among Windows PC and Linux/Unix workstations?
- What are the functions of a bridge, repeater, switch, modem, and NIC in computer networking and inter-networking?
- What is gateway in a network?
- Can you illustrate a small network design based on requirements?
- What is a DHCP server in a network?
- What is the common application of NAT in computer networking?
- What is DMZ in network design?
- What is IP masquerade in computer networking?
- Can you explain a few techniques to secure your wireless network?
- 1) Secure your wireless router or access point administration interface
- 2) Don't broadcast your SSID
- 3)Enable WPA encryption instead of WEP
- 4) Remember that WEP is better than nothing
- 5) Use MAC filtering for access control
- 6) Reduce your WLAN transmitter power
- 7) Disable remote administration
- Can you explain the main goals of network security, namely, confidentiality, integrity, authenticity, and availability?
- What are IDS?
- Network-based IDS and Host-based IDS
- Can you describe a simple technique of firewall?
- What is proxy servers?
- What is the difference between firewall and proxy server?
- Can you describe the main concepts and definition of VPN (Virtual Private Networks)?
- Can you state the different types of VPN?
- Can you compare symmetric encryption and asymmetric encryption?
- What is Digital Signature?
- Can you illustrate a common way of creating a digital signature?
- Can you explain the main concepts of IPSec?
- Can you explain the main concepts of SSL?
- IPSec and SSL are the two popular security protocols of the Internet. Can you compare them?
Thanks for Reading
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If you find any problem in this lecture note, please feel free to tell Steven via steven@findaway.hk.
