Computer Networks

Why are networks layered?

What is the order of layers (Internet protocol stack) starting from Top-Down?

What is the application layer for?

What is the transport layer for?

What is the network layer for?

What is the link layer for?

What is the physical layer?

Why do packets get encapsulated?

What layers is a switch capable of handling?

What layers is a router capable of handling?

What is meant by layer 2 & 3 devices?

What are some examples of network applications? Name at least 5.

What is the process of creating a network application?

What is the client-server architecture?

What is an IP address?

What is the P2P architecture?

In client-server architecture, what is meant by the client process and server process?

How do client processes and server processes work in P2P architectures?

What are sockets used for?

Why are port numbers needed when running client-server applications?

What are some examples of applications with well known ports?

What does the application layer protocol define?

What transport services do web applications need?

Transport service requirements: common apps.

This is not a question.

What are the properties of TCP?

What are the properties of UDP?

What are the three major components of electronic mail?

When it comes to electronic mail, what is a user agent component?

Describe mail servers.

Which transfer protocol does SMTP use?

What are the three phases of the SMTP protocol for transfers?

Which encoding format must SMTP messages be formed of?

SMTP scenario.

This is not a question. FYI UA stands for User Agent.

Sample SMTP interaction.

This is not a question.

What does IMF stand for?

What is the Internet Message Format?

Mail access protocol.

This is not a question.

What does POP stand for?

What does IMAP stand for?

The POP3 protocol

Describe the POP3 protocol

Describe the IMAP protocol

e-mail over HTTP.

What does MIME stand for?

What is the difference between sending an email directly from an SMTP client (i.e., Thunder Bird) and from a browser (Gmail)?

Describe MIME

What is a web page and what does it consist of?

How are web pages fetched?

Describe the client-server HTTP model.

If a base HTML-file contains references to other URLs, what happens?

Is HTTP stateless? Explain answer.

Does HTTP use UDP or TCP? Explain the process.

What does RTT stand for?

Define what RTT is.

Non-persistent HTTP: response time

Describe some of the fundamental issues with non-persistent HTTP.

Describe some of the advantages of persistent HTTP.

HTTP request message.

HTTP/1.0 & HTTP/1.1 method types.

HTTP response message.

What can cookies be used for?

What is a Web cache?

What are the advantages of Web caching?

How is it that caches act both as client and server?

What is an ISP?

Conditional GET (Web caching)

What does DNS stand for?

What is a DNS?

Distributed hierarchy of DNS

What does TLD stand for?

What is the purpose of TLD servers?

TLD, authoritative servers.

What are authoritative DNS servers?

Local DNS name server.

In regards to DNS, what is an iterative query?

What are the four different types of DNS servers?

How are local DNS servers optimized?

In regards to DNS, what is a recursive query?

What does TTL stand for?

How do local DNS servers update cache records?

What does RDT stand for?

What does UDT stand for?

How does RDT work?

How does UDT work?

Reliable data transfer.

What is the port number of TCP?

Explain some of the properties of TCP.

What is meant by a point-to-point protocol?

How are the window sizes of Go-Back-N and Selective Repeat set?

How are sequence numbers set in TCP?

How are ACKs made with TCP?

Does TCP use cumulative ACKs?

How are retransmissions handled in TCP?

What causes retransmissions in TCP?

How should timeouts be set in TCP?

How can RTT be estimated?

What may be an indication of network congestion in TCP?

What properties of Go-Back-N and Selective Repeat does TCP use?

What is the form of an IP address?

What is meant by throughput?

What are the 4 main types of delays a packet can suffer from when traveling from source to destination in a packet switching transfer protocol?

What is meant by the processing delay of a packet?

What is meant by the queuing delay of a packet?

What is meant by the transmission delay of a packet?

What is meant by the propagation delay of a packet?

What is the primary role of routers?

In TCP how does a sender increase transmission rate (window size), probing for usable bandwidth until loss occurs?

In regards to TCP, what does MSS mean?

What is meant by slow start in regards to TCP?

What is fair and unfair in regards to TCP?

What do routers do?

What is the difference between forwarding and routing?

What do virtual circuits do?

What are datagram networks?

What is ICMP and what is it used for?

What type of service does the network layer provide?

What does the best effort service of the network provide?

How do routers decide which link interface to forward a packet to based on the IP address of the packet?

What determines how long a datagram packet lives in the network before reaching its destination?

IP datagram format.

What does BGP stand for?

What does BGP do.

What is a subnet mask?

When it comes to links, what is meant by MTU?

What does NAT stand for?

What does NAT do and how does it work?