NWC Mooc 4 Exam Questions and Answers with Complete solutions

Which of the following protocols work at IP layer? 1 point ICMP ARP IGMP All of the above - ANSWER All of the above Which of the following packet header length cannot be used in an IPv4 packet header? 1 point ...

Which of the following protocols work at IP layer? 1 point ICMP ARP IGMP All of the above - ANSWER All of the above Which of the following packet header length cannot be used in an IPv4 packet header? 1 point 20 Bytes 30 Bytes 60 Bytes 64 Bytes - ANSWER 30 Bytes How many bits used for header checksum in IPv4 packets? 1 point 8 bits 16 bits 32 bits None of the above - ANSWER 16 bits What is the dotted notation of an IP address of 10000000 10000111 01000100 00000101 ? 1 point 128.135.65.5 128.133.68.5 128.135.68.5 128.135.65.5 - ANSWER 128.133.68.5 Given a network address 128.100.0.0, what is its network class type? 1 point Class A Class B Class C None of the above - ANSWER Class B Which of the following is provided at the IP layer 1 point Connectionless Best effort delivery service Both of the above None of the above - ANSWER You need to subnet a network that has 5 subnets, each with at least 16 hosts. Which will be your closest choice 1 point 255.255.255.224 255.255.255.192 255.255.255.240 255.255.255.248 - ANSWER 255.255.255.224 What is the subnetwork number of a host with an IP address of 172.16.66.0/21 1 point 172.16.48.0 172.16.64.0 172.16.0.0 172.16.36.0 - ANSWER 172.16.64.0 What is the first valid host on the subnetwork that the node 172.30.190.198/24 belongs to? 1 point 172.30.190.0 172.30.190.1 172.30.190.100 None of the above - ANSWER 172.30.190.1 Based on 1.1.1.0/24, the IP address would be: 1 point Class A Class B Class C Class D - ANSWER Class A 1. Question 1 Which of following is the range of IPv4 addresses spanned by Class C? 1 point 1.0.0.0 to 127.255.255.255 128.0.0.0 to 191.255.255.255 192.0.0.0 to 223.255.255.255 None of the above - ANSWER 192.0.0.0 to 223.255.255.255 2. Question 2 If a subnet needs to accommodate up to 500 hosts. How many bits for HostID would be sufficient? 1 point 5 9 8 7 - ANSWER 9 3. Question 3 Consider a Class B network, where the subnet ID takes 9 bits. What will be the subnet mask? 1 point 11111111 11111111 11111110 00000000 11111111 11111111 11111111 10000000 11111111 11111111 00000000 00000000 None of the above - ANSWER 11111111 11111111 11111111 10000000 4. Question 4 Given a subnet mask 255.255.255.240, how many hosts the subnet can support? 1 point 14 30 62 None of the above - ANSWER 14 5. Question 5 A host in an organization has an IP address 150.32.64.34 and a subnet mask 255.255.240.0. What is the address of this subnet? 1 point 150.32.64.16 150.32.64.24 150.32.64.0 150.32.64.32 - ANSWER 150.32.64.0 6. Question 6 What is the maximum number of IP addresses that can be assigned to hosts on a local subnet that uses the 255.255.255.224 subnet mask 1 point 14 15 30 62 - ANSWER 30 7. Question 7 When calculating usable hosts per subnet, the following formula is used 2^bits - 2. For what reason is two subtracted? (choose two) 1 point Multicast Unicast Broadcast Network - ANSWER Broadcast Network 8. Question 8 How many hosts can be addressed on 10.0.0.0/16? 1 point 16 254 65536 65534 - ANSWER 65534 9. Question 9 Which of the following is a valid IP host address given the network ID of 191.254.0.0 while using 11 bits for subnetting? 1 point 191.254.1.29 191.54.1.64 191.254.0.96 191.254.0.32 - ANSWER 191.254.1.29 10. Question 10 DISCO Corporation has been assigned the Class B network address 165.87.0.0. DISCO needs to divide the network into eight subnets. What subnet mask should be applied to the network to provide the most hosts per subnet? 1 point 255.255.248.0 255.255.224.0 255.255.192.0 255.255.240.0 - ANSWER 255.255.240.0 Question 1 Which class of IP addresses does CIDR performs aggregation on? 1 point Class C Class D Class A Class B - ANSWER Class C Using a CIDR notation, a prefix 205.100.0.0 of length 22 is written as 205.100.0.0/22. What network mask that the /22 notation indicates? 1 point 205.255.255.0 255.255.252.0 255.255.22.0 None of the above - ANSWER 255.255.252.0 Perform CIDR aggregation on the following /24 IP addresses: 128.58.24.0/24, 128.58.25.0/24, 128.58.26.0/24, 128.58.27.0/24. What is the CIDR outcome? 1 point 128.58.28.0/22 128.58.24.0/22 128.58.28.0/24 None of the above - ANSWER 128.58.24.0/22 Which protocol is used to assign temporary IP addresses to hosts? 1 point ICMP DHCP ARP None of the above - ANSWER DHCP In order to maximize the usage of limited IP addresses, which of the following protocol is commonly used 1 point NAT DHCP Both of the above None of the above - ANSWER Both of the above The internet protocol allows IP fragmentation so that datagrams can be fragmented into pieces small enough to pass over a link with a smaller MTU than the original datagram size 1 point True False - ANSWER True Which of the following statement is correct for IPv6 1 point Broadcast in IPv4 have been replaced with multicast in IPv6 There are 2.7 billion available addresses Does not support multiple multiple IPv6 address per interface Addresses are not hierarchical and are randomly assigned - ANSWER Broadcast in IPv4 have been replaced with multicast in IPv6 Question 9 Bootstrap Protocol (BOOTP) allows a diskless workstation to be remotely booted up in a network with TCP port designation for both client and server 1 point True False - ANSWER False In NAT operations, which of the following statements are correct (Select 3) 1 point NAT maps each private IP address and port number into shared global IP address and available port number Hosts inside private networks generate packets with private IP address and TCP/UDP port numbers Translation table allows packets to be routed ambiguously Translation table allows packets to be routed unambiguously - ANSWER NAT maps each private IP address and port number into shared global IP address and available port number Hosts inside private networks generate packets with private IP address and TCP/UDP port numbers Translation table allows packets to be routed unambiguously 1. Question 1 Packet is to be forwarded to a network with MTU of 592 bytes. The packet has an IP header of 20 bytes and a data part of 1484 bytes. Which of following maximum data length per fragment is legitimate? 1 point 568 592 572 562 - ANSWER 568 2. Question 2 What information is used as the entry of the lookup table in a Network Address Translation box? 1 point UDP port number IP address All of the above TCP port number - ANSWER All of the above 3. Question 3 IPv6 allows fragmentation at 1 point Source only Intermediate routers only Both source and intermediate routers None of the above - ANSWER Source only 4. Question 4 Which of following fields that IPv6 dropped from IPv4? 1 point All of the above Header checksum ID/flags/frag offset Header length - ANSWER All of the above 5. Question 5 in practical IPv6 application, a technology encapsulates IPv6 packets inside IPv4 packets, this technology is called 1 point IP tunneling Dynamic host configuration protocol Network address translation Routing - ANSWER IP tunneling 6. Question 6 Which fields in IP packet provide for fragmentation of datagrams to allow differing MTUs in the internet 1 point Fragmentation offset Type of service Identification Flags - ANSWER Fragmentation offset Identification Flags 7. Question 7 IPv6 has a much larger space of 1 point 2^8 2^16 2^32 2^128 - ANSWER 2^128 8. Question 8 Which of these statements are true of IPv6 representation 1 point Leading zeros in an IPv6 16 bit hexadecimal field are mandatory Every IPv6 interface contains at least one loopback address A single interface may be assigned multiple IPv6 addresses of any type The first 64 bits represent the dynamically created interface ID. - ANSWER Every IPv6 interface contains at least one loopback address A single interface may be assigned multiple IPv6 addresses of any type 9. Question 9 Which of the following statement is true for DHCP 1 point Used extensively to assign temporary IP addresses to hosts Allows ISP to maximize usage of their limited IP addresses Time threshold to enforce lease time All of the above - ANSWER All of the above 10. Question 10 In Network Address Translation (NAT), which of the following statement is true for a packet with an associated private IP address at the routers in the global internet 1 point Discarded due to the nature of the packet address Redirected to other routers for address confirmation Forwarded to the destination address in the packet header Create an exception and then forward the packet to the destination address in the header - ANSWER Discarded due to the nature of the packet address Which of following control is enabled in UDP? 1 point Flow control Error control Congestion control None of the above - ANSWER Which of following information is not used in UDP de-multiplexing? 1 point Destination IP address Source IP address Destination port number Source port number - ANSWER TCP adopts selective repeat ARQ protocol for flow control. In TCP flow control implementation, the window slides at 1 point Per-packet basis Per-byte basis Per-bit basis None of the above - ANSWER Per-byte basis Which flag bit in TCP header must be set when a TCP client initiates a three-way handshake? 1 point SYN ACK RST None of the above - ANSWER SYN Which flag bit in TCP header must be set when a TCP entity wants to terminate a connection? 1 point ACK SYN RST FIN - ANSWER In Transmission Control Protocol (TCP), When a segment carries a combination of data and control information, it uses a 1 point Port Number Sequence Number Source Number Slot Number - ANSWER Sequence Number Transmission Control Protocol (TCP), has same Checksum controlling like 1 point UDP TCP/IP ICMP IP - ANSWER UDP In TCP connection management, which of the following statements are true 1 point Select initial sequence numbers (ISN) to protect against segments from prior connections High bandwidth connection pose a problem Use global clock to select ISN sequence number Time for clock to go through a full cycle should be less than the maximum lifetime of a segment - ANSWER Select initial sequence numbers (ISN) to protect against segments from prior connections High bandwidth connection pose a problem In phases of congestion behavior, when arrival rate is greater than outgoing line bandwidth 1 point Congestion collapse Knee Congestion onset Light traffic - ANSWER Congestion collapse Which of the following services are provided by UDP 1 point IP De-multiplexing Error Checking All of the above - ANSWER All of the above 1. Question 1 When a TCP client initiates a three-way handshake with a sequence number x, what will be the acknowledgement number when the TCP server replies? 1 point x x + 1 x + y (where y is the sequence number proposed by TCP server) None of the above - ANSWER x + 1 2. Question 2 TCP header has a field called window size. What value is the value window size set to? 1 point Advertised window size for congestion control Advertised window size for flow control Round-trip delay None of the above - ANSWER None of the above 3. Question 3 In general, there are three phases of congestion behavior, i.e., light traffic, knee, congestion collapse. Which phase does TCP congestion avoidance maps to? 1 point Light traffic Knee Congestion collapse None of the above - ANSWER Knee 4. Question 4 When three duplicate acknowledgements arrive before timeout expires, what will TCP congestion control algorithm reset congestion threshold to for fast re-transmission and fast recovery? 1 point Reset congestion threshold to 1 Reset congestion threshold to half of the current congestion window size Reset congestion threshold to the current congestion window size None of the above - ANSWER Reset congestion threshold to half of the current congestion window size 5. Question 5 Assume a TCP source writes a 1200-byte message in one write. Which of following is possible for the destination to receive the message? 1 point All of the above It receives a 1200-byte message in one read It receives three reads of 400 bytes each It receives two reads of 600 bytes each - ANSWER All of the above 6. Question 6 The process of combining multiple outgoing protocol streams at the Transport and Network layers in TCP/IP is called Multiplexing 1 point True False - ANSWER True 7. Question 7 TIMELY provides a framework for rate control that depends on transport layer protocol for reliability 1 point True False - ANSWER False 8. Question 8 The operation of TCP congestion control can be divided into three phases, which phase requires that the congestion window size be increased by one segment upon receiving an ACK from receiver 1 point Congestion avoidance Slow start Congestion None of the above - ANSWER Slow start 9. Question 9 In a router, the control of the transmission rate at the sender's side such that the router's buffer will not be over-filled is called _________ if sender is transmitting too fast 1 point Network under-utilization Host flooding Network congestion None of the above - ANSWER Network congestion 10. Question 10 Congestion control is associated with the window size field 1 point True False - ANSWER False Which of following protocol allows a host to signal its multicast group membership to its attached routers? 1 point ICMP IGMP OPSF None of the above - ANSWER IGMP Which of following statements most accurately describes the reverse-path broadcasting? 1 point It assumes that the shortest path from the source to a given router should be the same as the shortest path from the router to the source Each link in the network to be symmetric Each packet is forwarded by a router exactly once All of the above - ANSWER It assumes that the shortest path from the source to a given router should be the same as the shortest path from the router to the source Which class of IP address does the reverse-path broadcasting uses? 1 point Class B Class A Class C Class D - ANSWER Class D Attackers attempt to gain unauthorized access to server. What type of network security threat it imposes? 1 point Client imposter Server imposter Man-in-Middle None of the above - ANSWER Client imposter In mobile IP, when a home agent wants to send a packet to a mobile host in a foreign network, each IP packet at the home agent will be encapsulated with an outer IP header. What is the destination IP address in the outer IP header? 1 point Care-of address Mobile host's address Home agent's address None of the above - ANSWER Care-of address An IP address associated with a mobile node while visiting a foreign link 1 point Home address Handover address Care of address Home link - ANSWER Care of address TCP SYN flood attack exploits the TCP three-way handshake 1 point True False - ANSWER True In multicast communication, relationship is 1 point one to one many to one one to many one to all - ANSWER one to many 1. Question 1 What is the security requirement in case of Denial of Service? 1 point Privacy Availability Integrity None of the above - ANSWER Availability 2. Question 2 In a software defined network (SDN), which of the architectural layer is responsible for switch configuration and forwarding instruction? 1 point Middle layer Infrastructure layer Security layer None of the above - ANSWER Middle layer 3. Question 3 What is the security requirement in case of Malicious Code? 1 point Privacy Availability Integrity All of the above - ANSWER All of the above