export_week 14 chapter 13 ethernet and tcpip networking

Question 1

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Domain Names

Answer 1

▪ Hierarchical system of network address identifiers used throughout the Internet and on local area networks, intranets and extranets ▪ Created so users would not have to memorize IP addresses

Question 2

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what is the Domain name resolution ?

Answer 2

translates domain names into IP addresses

Question 3

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what does DNS Domain Name System do ?

Answer 3

▪ Uses a massive distributed database containing a directory system of servers

▪ Each entry contains a domain name and an associated IP addres

Question 4

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Domain Name System (DNS) diagram

Answer 4

DNS Server Hierarchy

Question 5

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The Elements of a Domain Name

Question 6

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Top Domain Name Registrations

Question 7

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Domain Name Resolution diagram

Answer 7

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Question 8

what is DOEs Transport Layer ▪ TCP protocol?

Answer 8

▪ TCP protocol ▪ Sends a packet to TCP at the destination site, requesting a connection ▪ Handshaking – back and forth series of requests and acknowledgments

Question 9

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▪ If handshaking negotiations are successful in the transport layer ?

Answer 9

▪ If handshaking negotiations are successful, a connection is opened

▪ Connection is logically full-duplex

Question 10

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Three-Way TCP Connection Handshake Diagram

Answer 10

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Question 11

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TCP Segment Format Diagram

Question 12

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Network Layer IP protocol?

Answer 12

▪ IP protocol ▪ Responsible for relaying packets from the source end node to the destination end node through intermediate nodes ▪ Performed using datagram packet switching and logical IP addresses ▪ Best-attempt unreliable service ▪ Size of datagram ranges from 20 to 65,536 bytes ▪ Header size between 20 and 60 bytes

Question 13

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IPv4 Addresses

Answer 13

▪ Registered and allocated by ICANN ▪ 32 bits long divided into 4 octets ▪ Assigned in blocks of contiguous addresses ▪ Number of addresses is a power of two

Question 14

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IPv4 Addresses ▪ Divided into three levels?

Answer 14

▪ Network address ▪ Subnetworks (subnets) ▪ Hosts (nodes)

Question 15

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what does Masks do ?

Answer 15

▪ Used to separate the different parts of the address

Question 16

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IPv4 Datagram Format Diagram ?

Question 17

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IP Addresses Diagram ?

Answer 17

IP Block Addresses

Question 18

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IP Addresses IP Hierarchy and Subnet Mask Diagram ?

Answer 18

IP Hierarchy and Subnet Mask

Question 19

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Reseved IP Addresses

Question 20

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Two methods to distribute IP addresses more efficiently:?

Answer 20

1. Use of private network IP addresses behind a router 2. Dynamic Host Configuration Protocol (DHCP)

Question 21

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what does Dynamic Host Configuration Protocol (DHCP) do ?

Answer 21

Maintain a bank of available IP addresses and assign them dynamically to computers for use when the computers are attached to the network Method often used by large organizations, DSL and cable providers

Question 22

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what does DHCP Client and server ?

Answer 22

* DHCP client on computer or network device broadcasts a query to locate the DHCP server * DHCP server responds with a lease which includes an IP address, domain name of network, IP address of DNS server, subnet mask, IP address of gateway and other configuration parameters

Question 23

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Operation of IP two major functions?

Answer 23

1. ▪ Routes datagrams from node to node until they reach their destination node 2. ▪ Translates IP addresses to physical addresses before it passes the packets to the data link later for delivery

Question 24

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(ARP)

Answer 24

Address Resolution Protocol

Question 25

# , tab when is the (ARP) network implemented ?

Answer 25

▪ Implemented at the network layer

Question 26

# , tab what does ARP do ?

Answer 26

▪ Translation of IP address to physical address at each intermediate node until destination is reached ▪ A broadcast of the IP address is sent to every node on the network. The matching node responds with a physical address ▪ Physical address (MAC address in the case of Ethernet) is sent in frame to the data link layer At final destination, the packet is passed up to the transport layer for deployment to the application layer

Question 27

# , tab Data Link Layer what is this responsible for ?

Answer 27

Layer responsible for transmitting a packet from one node to the next node

Question 28

# , tab how is node access defined ?

Answer 28

Node access defined by the medium access control (MAC) protocol ▪ Steer data to its destination ▪ Detect errors ▪ Prevent collisions

Question 29

# , tab what does Ethernet (CSMA-CD)?

Answer 29

▪ Predominant medium-access protocol for local area networks ▪ Standard Ethernet packet is a frame (see next slide)

Question 30

# , tab Ethernet Frame

Answer 30


Question 31

# , tab Hub-Based Ethernet 

Answer 31

\* Simple means of wiring bussed Ethernet together \* Logically still a bus network \* CSMA-CD

Question 32

# , tab when does the collision happens in the hub- based Ethernet happen ?

Answer 32

Collision ▪ Occurs when multiple nodes access the network in such a way that their messages become mixed and garbled

Question 33

# , tab what is Network propagation delay ?

Answer 33

Amount of time that it takes for one packet to get from one end of the network to the other

Question 34

# , tab when is gthe hub based Etherent work ?

Answer 34

▪ Adequate for networks with light traffic

Question 35

# , tab what Switched Ethernet do ?

Answer 35

1. Permits point-to-point connection of any pair of nodes 2. Multiple pairs can be connected simultaneously 3. Possible to connect nodes in full-duplex mode 4. Each pair of connections operates at the maximum bit rate of the network

Question 36

# , tab (QoS)

Answer 36

Quality of Service

Question 37

# , tab wh/at does QOS do

Answer 37

. 1. Methods to reserve and prioritize channel capacity to favor packets that require special treatment 2. Service guarantees from contract carrier services that specify particular levels of throughput, delay and jitter

Question 38

# , tab Jitter

Answer 38

variation in delay from packet to packet

Question 39

# , tab Differentiated service (DiffServ) about

Answer 39

1. ▪ 8-bit (DS) field in IP header 2. ▪ Set by the application at the sender or by the first node 3. ▪ Diffserv capable nodes such as routers can then prioritize and route packets based on the packet class

Question 40

# , tab Network Security Categories

Answer 40

1. Intrusion 2. Confidentiality 3. Authentication 4. Data integrity and non-repudiation 5. Assuring network availability and access control

Question 41

# , tab Intrusion

Answer 41

Keeping network and system resources free from intruders

Question 42

# , tab Confidentiality

Answer 42

Keeping the content of data private

Question 43

# , tab Authentication

Answer 43

Verifying the identity of a source of data being received

Question 44

# , tab Data integrity and non-repudiation

Answer 44

Protecting the content of data communication against changes and verifying the source of the message

Question 45

# , tab Assuring network availability and access control

Answer 45

Keep network resources operational and restricting access to those permitted to use them

Question 46

# , tab ▪ Network intrusions how ?

Answer 46

▪ Packet sniffers read data in a packet as it passes through a network ▪ Probing attacks to uncover IP address / port numbers that accept data packets

Question 47

# , tab what are Physical and Logical Restriction ?

Answer 47

Physical and Logical Restriction ▪ Limit access to wiring and network equipment ▪ Firewall ▪ Private networks

Question 48

# , tab Encryption

Answer 48

1-Symmetric key cryptography Both key used for encryption and decryption Both sender and receiver use the same key which makes security difficult 2- Public key cryptography Two different keys are used for encryption and decryption

Question 49

# , tab MPLS

Answer 49

(Multi-Protocol Label Switching) Creates a virtual circuit over packet switched networks to improve forwarding speed of datagrams

Question 50

# , tab ATM

Answer 50

(Asynchronous Transfer Mode) ▪ Partial-mesh network technology in which data passes through the network in cells (53-byte packets)

Question 51

# , tab SONET and SDH

Answer 51

(Synchronous Optical Network) and (Synchronous Digital Hierarchy) Protocol that uses fiber optic to create wide area networks with very high bit rates over long distances

Question 52

# , tab Frame Relay

Answer 52

▪ Slow, wide area network standard A standardized wide area network technology that specifies the physical and logical link layer of digital telecommunications channels using a packet switching methodology