Internet and TCP/IP Flashcards
Is the internet a homogeneous network?
No,the internet is a vast collection of different networks that use a common protocol family;primarily the Internet Protocol (IP).
How did the internet develop into its current form?
The internet developed somewhat organically and was never specifically planned or designed by one individual.
Who manages the internet?
The internet is managed by several independent standardization bodies that guide its development in a decentralized manner.
What is the role of the Internet Society (ISOC)?
The Internet Society (ISOC) is responsible for maintaining and developing the infrastructure of the internet.
What does the Internet Research Task Force (IRTF) do?
The IRTF promotes research relevant to the future development of internet protocols;applications;architecture;and technology.
How does the Internet Architecture Board (IAB) contribute to the internet?
The IAB accompanies the standardization activities of the Internet Engineering Task Force (IETF) and the research activities of the IRTF;providing advisory support to the ISOC.
What is the focus of the Internet Engineering Task Force (IETF)?
The IETF focuses on the technical development and standardization of the internet.
What role does the Internet Corporation for Assigned Names and Numbers (ICANN) play?
ICANN coordinates the allocation of unique names and addresses used on the internet.
What is the function of the Internet Assigned Numbers Authority (IANA)?
IANA is responsible for the global allocation of IP addresses and is a division of ICANN.
What is a Regional Internet Registry (RIR)?
An RIR is an organization entrusted with the regional allocation of internet addresses.
How many RIRs are there worldwide and what are their roles?
- There are five RIRs, each serving specific continents or regions:
- AFRINIC serves Africa.
- ARIN serves the USA and Canada.
- APNIC serves the Asia-Pacific region.
- LACNIC serves Latin America and the Caribbean.
- RIPE NCC serves Europe, the Middle East, and Central Asia.
What period marked the origins of the internet?
The origins of the internet date back to the late 1950s.
How did the Cold War influence the early internet?
During the Cold War;the U.S. Department of Defense aimed to create a meshed data network with redundancy;as a countermeasure to make it more resilient to attacks;compared to the vulnerable hierarchical networks of the time.
Why was a meshed network chosen over a hierarchical network?
A meshed network was more resilient;as the loss of a few nodes would not isolate parts of the network;unlike in a hierarchical network where removing key nodes could break the network.
Which organization assisted the Department of Defense with network planning?
The RAND Corporation;a think tank;supported the Department of Defense in planning the network.
What key technology did RAND Corporation recommend for this network?
RAND Corporation recommended packet-switching technology over the circuit-switching used in traditional telephone networks.
Why did AT&T decline to build a prototype of the planned network?
AT&T declined because it believed that a nationwide meshed network was technically unfeasible.
What agency took over network development support;and what is it known as today?
The Advanced Research Projects Agency (ARPA);now known as the Defense Advanced Research Projects Agency (DARPA);supported further research into packet-switching networks.
What was ARPANET;and when did it begin?
ARPANET was the first packet-switching network;launched in 1969;connecting four universities and research institutes in California and Utah.
What two types of nodes formed the ARPANET?
ARPANET was formed by hosts (computing facilities at each site) and Interface Message Processors (IMP);which acted as routers.
How fast were ARPANET’s initial connection line compared to modern DSL?
ARPANET’s lines had a capacity of 56 kbit/s;which is about 1000 times slower than the 16–250 Mbit/s of modern DSL connections.
What three types of protocols were needed in ARPANET’s protocol stack?
The protocol stack included:IMP-to-IMP for network section communication;Host-to-IMP for message injection into the network; Host-to-host at the top of the stack
How quickly did ARPANET expand after its launch?
By July 1970;ARPANET had grown from 4 to 15 connected sites.
What protocol stack was developed in 1973 for improved network communication?
The TCP/IP protocol stack was developed for enhanced network-to-network and host-to-host communication.
Why did the National Science Foundation (NSF) become involved with network development?
The NSF recognized ARPANET’s value for scientific research but wanted a network more accessible to universities and research institutions;as ARPANET required Defense Department approval for access.
What was NSFNET;and who was its intended audience?
NSFNET was a packet-switching network created to provide access to universities;research institutions;libraries;and museums.
What company was formed to commercialize NSFNET;and what eventually happened to it?
Advanced Networks and Services (ANS) was created to promote a commercialized network;merging with NSFNET to form ANSNET;which was later sold to AOL in 1995;increasing commercialization.
How did other countries contribute to the global internet structure?
Other countries established research networks similar to ARPANET and NSFNET;connecting them through long-distance links;submarine cables;and satellites;which laid the foundation for the global internet.
What is the current structure of the internet and who can access it?
Today’s internet is highly diverse, including wide area networks, DSL, broadband cable, mobile networks, fiber-optics, and satellite systems, accessible to both private households and businesses via internet service providers.
Which protocols are now central to global internet communications?
The Internet Protocol (IP) and its related protocols;such as TCP
What do the terms “TCP/IP protocol stack” and “internet protocol family” refer to?
They refer to a group of network protocols that have emerged during the development of the internet.
What layer of the OSI model does the Internet Protocol (IP) belong to?
The Internet Protocol (IP) belongs to the third layer of the OSI model.
What is the primary purpose of the Internet Control Message Protocol (ICMP)?
ICMP is used by network devices to exchange error messages and diagnostic or routing information.
Describe the Transmission Control Protocol (TCP).
TCP is a connection-oriented transport protocol in the fourth layer of the OSI model;which guarantees reliable delivery of data streams through numbered packets and an automatic repeat request (ARQ) mechanism.
How does the User Datagram Protocol (UDP) differ from TCP?
UDP is a connectionless transport protocol that does not guarantee reliable delivery of packets;unlike TCP.
How many layers does the TCP/IP reference model have?
The TCP/IP reference model has four layers.
What is a notable difference between the TCP/IP model and the OSI model regarding protocol layers?
The TCP/IP model does not include protocols between the transport and application layers and disregards the physical layer.
What is the function of the Link Layer in the TCP/IP model?
The Link Layer serves as the interface to the hardware
What does the Address Resolution Protocol (ARP) do?
ARP allows computers and network devices to inquire about the MAC address corresponding to a specific IP address via a broadcast.
What protocol has replaced ARP in modern networks using IPv6?
The Neighbor Discovery Protocol (NDP) has replaced ARP in IPv6 networks.
What are the two versions of the Internet Protocol currently in use?
The two versions are IPv4 (the older version) and IPv6 (the newer version).
What is the primary commonality between IPv4 and IPv6?
Both are packet-switching protocols used for routing data packets across networks.
How is an IPv4 address formatted?
An IPv4 address consists of four bytes;typically written in decimal notation and separated by dots (e.g.
What does a subnet mask indicate in an IPv4 address?
The subnet mask specifies the number of bits that make up the network element of the IP address.
How many theoretically possible IPv4 addresses are there?
There are approximately 4.3 billion possible IPv4 addresses.
How does IPv6 expand the number of available addresses?
IPv6 uses 128 bits for addresses;resulting in an enormous quantity of possible addresses (approximately 4.3 million to the power of four).
What is the significance of Network Address Translation (NAT)?
NAT allows multiple devices on a local network to share a single public IP address;making it possible for devices to access the internet without needing their own unique addresses.
What is contained in the message header of an IPv4 packet?
The header includes fields such as version
What happens when an IPv4 packet is sent to a device within the local network?
The sender queries the MAC address of the receiver using ARP and delivers the packet directly.
How does the TCP session establishment process work?
TCP uses a three-way handshake: the client sends a SYN packet;the server responds with a SYN-ACK packet;and the client sends an ACK packet to establish the connection.
How does TCP ensure reliable data transmission?
TCP uses sequence numbers
What is the purpose of well-known ports in TCP and UDP?
Well-known ports allow clients to connect to specific services on servers (e.g;HTTP typically uses port 80;while SMTP uses port 25).
What is the primary function of the User Datagram Protocol (UDP)?
UDP delivers individual packets (datagrams) without establishing a connection and does not guarantee reliable delivery.
What are the four higher-layer protocols discussed in the TCP/IP family?
The four higher-layer protocols are Dynamic Host Configuration Protocol (DHCP);Domain Name System (DNS);Hypertext Transfer Protocol (HTTP);and Simple Mail Transfer Protocol (SMTP).
Which two protocols primarily operate in the background?
The two protocols that primarily operate in the background are DHCP and DNS.
What are the primary functions of DHCP?
DHCP provides automated support for IP address assignment and can send other configuration parameters;such as subnet masks and router IP addresses.
How does a DHCP client find out its assigned IP address?
A DHCP client sends a broadcast request (DHCPDISCOVER) to the DHCP server;which then responds with available IP addresses (DHCPOFFER). The client selects one and uses it.
What are the three methods of IP address assignment by a DHCP server?
The three methods are static assignment;dynamic assignment;and automatic assignment.
What role does the Domain Name System (DNS) serve?
DNS serves as a worldwide directory for resolving domain and host names into IP addresses for publicly accessible internet services.
What is a fully qualified domain name (FQDN)?
An FQDN is a unique name within the DNS hierarchy that consists of a hostname and a domain name;structured in a hierarchical manner with dots separating each component.
How does a computer resolve an FQDN to an IP address?
The computer checks its local DNS cache first; if not found;it queries a local name server;which may refer to higher-level DNS servers until the IP address is resolved.
What is the purpose of the Hypertext Transfer Protocol (HTTP)?
HTTP enables web browsers to retrieve HTML pages from web servers by sending HTTP requests and receiving responses.
Describe the structure of a URL
A URL typically consists of the protocol;user;password;host;port;path;query parameters;and fragment.
What are the two types of HTTP requests mentioned and what are their purposes?
The two types are GET, which retrieves resources, and POST, which submits data to modify server resources.
What are some common HTTP status codes and their meanings?
200 OK: The request was successful;403 Forbidden: Access denied due to authorization issues;404 Not Found: The requested resource could not be found;500 Internal Server Error: An unexpected condition occurred on the server.
What is the function of Simple Mail Transfer Protocol (SMTP)?
SMTP is used to send and forward emails in computer networks.
What other protocols are commonly used for receiving emails?
The commonly used protocols for receiving emails are Post Office Protocol Version 3 (POP3) and Internet Message Access Protocol (IMAP).
What are the key aspects of security in information technology?
Key aspects include confidentiality;integrity;and availability of data.
How does TCP ensure reliability in communication?
TCP ensures reliability by retransmitting corrupted or lost packets.
What is the role of Transport Layer Security (TLS) in internet communication?
TLS provides encryption to ensure the confidentiality and integrity of transmitted data over TCP connections.
What is the difference between TLS and IPSec in terms of encryption?
TLS operates at the application layer (or upper transport layer in TCP/IP) and encrypts data in transit;while IPSec operates at the internet layer and provides encryption directly for IP packets.
Why is end-to-end encryption necessary in email communication?
End-to-end encryption ensures that emails remain confidential and secure throughout their transmission;protecting against unauthorized access and manipulation.
What are S/MIME and PGP used for?
S/MIME and PGP are used for providing effective end-to-end encryption and authentication in email communication.
What does TCP/IP refer to?
TCP/IP refers to a reference model;standard protocols for internet traffic;and a family of complementary network protocols.
How many layers are in the TCP/IP model?
The TCP/IP model comprises four distinct layers.
How does the TCP/IP model compare to the OSI model?
The TCP/IP model somewhat mirrors the OSI model but is notably less detailed.
What are the two main standard protocols in the TCP/IP model?
The two main standard protocols are TCP (Transmission Control Protocol) and IP (Internet Protocol).
What role do ARP and NDP play in the TCP/IP model?
ARP (Address Resolution Protocol) and NDP (Neighbor Discovery Protocol) are link layer protocols that map IP addresses to hardware addresses.
What protocol complements the IP protocol within the internet layer?
The ICMP (Internet Control Message Protocol) complements the IP protocol by exchanging routing and diagnostic data.
What are the transport layer protocols in the TCP/IP model?
The transport layer includes TCP (reliable transport protocol) and UDP (User Datagram Protocol);which is unreliable.
What types of services do the application layer protocols provide?
Application layer protocols provide services such as DHCP (Dynamic Host Configuration Protocol);DNS (Domain Name System);HTTP (Hypertext Transfer Protocol)
What is the purpose of DHCP and DNS in the application layer?
DHCP provides IP address assignment
Why do applications that transfer sensitive data require additional security?
They require additional security to protect confidentiality and integrity.
What is the function of encryption protocols like TLS in the TCP/IP model?
TLS (Transport Layer Security) enhances communications security by providing encryption;operating between the transport and application layers.
What is the distinction between TCP and UDP?
TCP is a reliable transport protocol that ensures data delivery;while UDP is a simpler and less reliable protocol that does not guarantee delivery.
