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Computer Networks Final Exam 2025 latest Questions
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In Network Encapsulation, when a segment is added with network layer header information, then it is called a Datagram The application that is used to find the "read" end-to-end internet delay is Traceroute The Packet delay that occurs when a packet travels over a wire is Propagation delay The components of a cable access network is Cable Modem, CMTS, Cable Headend, Splitter The which media, signals propagate in a solid media? Guided Media A fiber optic cable is a Glass fiber carrying light pulses and each pulse is a bit
In which one of the following attacks, the attackers make resources (server or bandwidth) unavailable to legitimate traffic by overwhelming resources with bogus traffic? Denial of Service (DoS) A radio signal is a Signal carried in electromagnetic spectrum In which one of the following attackers, the attacker sits on a promiscuous network interface ad reads/records all packers (e.g. including passwords) passing by? Packet Sniffing The components of a Digital Subscriber Line (DSL) access network are... Splitter, DSL Modem, DSL Access Multiplexer, Telephone Network The process where the end-to-end resources are allocated between source and destination to send of receive data is called as Circuit Switching The sources of packet delay in an end-to-end transmission are... Processing Delay, Propagation Delay, Queueing delay, Transport Delay The data rate (bits/sec) at any given point of time is called as Instantaneous Throughput
Chunks The underlying transport layer protocol used by FTP is TCP In which type of DNS query is the load on the local DNS server? Iterative Query The door through which a process sends/receives its messages to/from is called Socket The transport layer protocols are... *********** TCP In a client—server architecture There is an always-on host called the server The protocol that offers unreliable data transfer is UDP Which one of the following DNS RR records gets the IP address
A record What are the "in-band" application layer protocols? HTTP What is the control port for FTP? 21 The services provided by DNS are... Load Distribution, Host Aliasing, Mail Server Aliasing, Host to IP translation What are the "out-of-band" application layer protocols? FTP The possible network architectures for network communication are... ********** Client-Server Architecture The underlying transport layer protocol used by Telnet is... TCP In which type of DNS query is the load in the DNS server?
What is the network edge? Hosts and applications considering of clients and servers Servers are often found in Data centers What is the network core? interconnected routers, network of networks The DSL Access network uses... Existing telephone line to central office DSLAM. What is frequency division multiplexing? Different channels transmitted in different frequency bands What is HFC? Hybrid Fiber Coax What is the physical aspect of the Cable Network Network of cable, fiber attaches homes to ISP router.
In Cable Networks, homes share Access network to cable headend What are the components of a home network? Cable or DSL Modem, Wireless Access Point, Wired Ethernet, Router/Firewall/NAT What are the components of an Enterprise Access Network? Ethernet switch, institutional link to ISP, institutional router, mail and web servers What are wireless access networks? A network where wireless access networks connect to the end system router What is guided media? What is Layer 1 Physical Layer What is a Layer 1 Device? Wires
What does the session layer do? synchronization, checkpointing, recovery of data exchange What is Layer 6? Presentation What does the Presentation Layer do? Allows applications to interpret meaning of data What is Layer 7? Application Layer What is the field of network security? How bad guys can attack computer networks, how we can defend against attacks, how to design attack-prrof architectures How long was ARPAnet in service? From 1967 to the early 1990s When was the first ARPAnet node operational? 1969
When did the World Wide Web become a thing? early 1990s When did SMTP become a thing? 1982 When was DNS defined? 1983 When was FTP defined? 1985 What are some examples of application architectures? Client-Server and Peer-to-Peer The server IP address is always permanent The client IP address is always dynamic P2P architecture does not have
identifier host devices have a unique 32-bit address The identifier in a process includes IP address and port numbers associated with process on host Open Protocols include RFCs, HTTP, SMTP Proprietary Protocols include Skype What are the transport service requirements? Data integrity, timing, throughput, security What does TCP provide? Reliable transport, flow control, congestion control What does TCP not provide?
Timing, minimum guaranteed throughput, security TCP is a _______________ protocol Connection oriented What does UDP service provide? Unreliable data transfer What does UDP not provide? Reliability, flow control, congestion control, timing, throughput guarantee, security, or connection set up UDP is a ___________ protocol Connectionless 200 OK 301 Moved Permanently 400
ISP
FTP
File Transfer Protocol FTP runs on RFC 959 In FTP, the client initiates transfer In FTP, the server is the remote host What protocol does FTP use TCP The server port for FTP is port 20 The three major components for electronic mail are
User agents, mail servers, SMTP The User Agent is What users read the emails on What are the components of mail servers? Mailbox, message queue, SMTP What are the three phases of direct transfer Handshake, transfer, closure What does SMTP stand for Simple Mail Transfer Protocol What are the three protocols of SMTP POP, IMAP, HTTP What is the DNS? The Domain Name System (DNS) converts domain names or host names into IP addresses. Why is DNS not centralized?
DNS, streaming What services are unavailable between TCP and UDP? Delay and bandwidth guarantees What are the two protocols of the transport layer? TCP and UDP How does demultiplexing work? Host recieves IP datagram and the host uses IP addresses and port numbers to direct segment to appropriate socket In connectionless demultiplexing... the host will check the destination port and IP address and direct it to the appropriate socket Connection oriented demultiplexing... Uses both source and dest IP Underlying channel perfectly reliable and separate FSMs for sender and reciever. These are traits of RDT 1.
Underlying channel may flip bits in packet, introduces checksums, ACKs, and NAKs, risk of duplicates. These are traits of RDT 2. Introduces sequence number, checks for corrupted ACK/NAK, twice as many states, checks for duplicates at reciever. These are traits of RDT 2. No more NAKs, duplicate ACK invokes retransmit. These are traits of RDT 2. Underlying channel can also lose packets, waits for timeout. These are traits of RDT 3. What are the features of TCP fast retransmit? Long timeout period, detect lost segment via duplicate ACK What are the features of TCP flow control? Sender limits amount of unacked data to reciever's rwnd value, meaning the buffer will not overflow What are the steps of a 2-way handshake? ESTAB, ESTAB
