Podcast
Questions and Answers
What is the primary service that TCP provides to application processes?
What is the primary service that TCP provides to application processes?
What are the packets exchanged between TCP peers referred to as?
What are the packets exchanged between TCP peers referred to as?
Which TCP header field contains the sequence number for the first byte of data in a segment?
Which TCP header field contains the sequence number for the first byte of data in a segment?
Which of the following fields is not involved in TCP’s sliding window algorithm?
Which of the following fields is not involved in TCP’s sliding window algorithm?
Signup and view all the answers
How does the destination host receive and handle TCP segments?
How does the destination host receive and handle TCP segments?
Signup and view all the answers
Why does TCP not transmit individual bytes over the Internet?
Why does TCP not transmit individual bytes over the Internet?
Signup and view all the answers
What does the AdvertisedWindow field convey in TCP communication?
What does the AdvertisedWindow field convey in TCP communication?
Signup and view all the answers
In a TCP segment, what type of protocol is it considered to be?
In a TCP segment, what type of protocol is it considered to be?
Signup and view all the answers
What is the length of the TCP sequence number?
What is the length of the TCP sequence number?
Signup and view all the answers
Why is it important for the sequence number space to be twice as large as the window size?
Why is it important for the sequence number space to be twice as large as the window size?
Signup and view all the answers
What time limit is set for how long packets can survive in the Internet?
What time limit is set for how long packets can survive in the Internet?
Signup and view all the answers
What could happen if the sequence number wraps around within a 120-second time frame?
What could happen if the sequence number wraps around within a 120-second time frame?
Signup and view all the answers
How does the sequence number affect TCP connections over time?
How does the sequence number affect TCP connections over time?
Signup and view all the answers
What determines the speed at which data can be transmitted over the Internet in relation to the sequence number?
What determines the speed at which data can be transmitted over the Internet in relation to the sequence number?
Signup and view all the answers
What is one potential consequence of a byte being sent with the same sequence number at a later time?
What is one potential consequence of a byte being sent with the same sequence number at a later time?
Signup and view all the answers
Why is it crucial to prevent sequence number wraparound during active TCP connections?
Why is it crucial to prevent sequence number wraparound during active TCP connections?
Signup and view all the answers
What must the 16-bit AdvertisedWindow field allow the sender to achieve?
What must the 16-bit AdvertisedWindow field allow the sender to achieve?
Signup and view all the answers
If the receiver has sufficient buffer space, what can it potentially do with the advertised window?
If the receiver has sufficient buffer space, what can it potentially do with the advertised window?
Signup and view all the answers
What is the significance of maintaining a window that accommodates a full delay × bandwidth product?
What is the significance of maintaining a window that accommodates a full delay × bandwidth product?
Signup and view all the answers
What is the assumed round-trip time (RTT) mentioned in conjunction with window size requirements?
What is the assumed round-trip time (RTT) mentioned in conjunction with window size requirements?
Signup and view all the answers
How does TCP decide when to transmit a segment?
How does TCP decide when to transmit a segment?
Signup and view all the answers
Which action does Host A perform to initiate communication with Host B?
Which action does Host A perform to initiate communication with Host B?
Signup and view all the answers
What returns the actual data received after the read operation in a TCP connection?
What returns the actual data received after the read operation in a TCP connection?
Signup and view all the answers
What does the listen operation indicate in the context of a TCP server?
What does the listen operation indicate in the context of a TCP server?
Signup and view all the answers
Which of the following stages in a TCP connection involves blocking until a connection request is received?
Which of the following stages in a TCP connection involves blocking until a connection request is received?
Signup and view all the answers
In the TCP connection establishment process, what happens when Host A calls connect?
In the TCP connection establishment process, what happens when Host A calls connect?
Signup and view all the answers
What is the main function of UDP in the context of network communication?
What is the main function of UDP in the context of network communication?
Signup and view all the answers
Which characteristic is NOT associated with UDP?
Which characteristic is NOT associated with UDP?
Signup and view all the answers
What type of control focuses on preventing senders from overrunning the capacity of receivers?
What type of control focuses on preventing senders from overrunning the capacity of receivers?
Signup and view all the answers
What is a major limitation of transport protocols operating over a network?
What is a major limitation of transport protocols operating over a network?
Signup and view all the answers
Which protocol is characterized as reliable and connection-oriented?
Which protocol is characterized as reliable and connection-oriented?
Signup and view all the answers
What does TCP use to manage the flow of data between sender and receiver?
What does TCP use to manage the flow of data between sender and receiver?
Signup and view all the answers
What characteristic of TCP allows it to adapt to different round-trip times (RTTs)?
What characteristic of TCP allows it to adapt to different round-trip times (RTTs)?
Signup and view all the answers
Which of the following is NOT a service typically provided by transport protocols?
Which of the following is NOT a service typically provided by transport protocols?
Signup and view all the answers
Which application is commonly associated with UDP?
Which application is commonly associated with UDP?
Signup and view all the answers
In what way does TCP ensure reliable communication?
In what way does TCP ensure reliable communication?
Signup and view all the answers
How does flow control differ from congestion control in network protocols?
How does flow control differ from congestion control in network protocols?
Signup and view all the answers
Which of the following statements about error detection in UDP is correct?
Which of the following statements about error detection in UDP is correct?
Signup and view all the answers
How does TCP handle the possibility of message reordering during transmission?
How does TCP handle the possibility of message reordering during transmission?
Signup and view all the answers
What mechanism is crucial for TCP to learn the sending capacity of the network?
What mechanism is crucial for TCP to learn the sending capacity of the network?
Signup and view all the answers
What is the main limitation of ACKs in relation to retransmitted data?
What is the main limitation of ACKs in relation to retransmitted data?
Signup and view all the answers
What is a key instruction of the Karn/Partridge Algorithm in terms of sampling RTT?
What is a key instruction of the Karn/Partridge Algorithm in terms of sampling RTT?
Signup and view all the answers
How does the Karn/Partridge Algorithm address timeouts during retransmissions?
How does the Karn/Partridge Algorithm address timeouts during retransmissions?
Signup and view all the answers
What issue regarding congestion does the Karn/Partridge Algorithm not resolve?
What issue regarding congestion does the Karn/Partridge Algorithm not resolve?
Signup and view all the answers
Which aspect of Sample RTTs is not adequately addressed by the original computation method?
Which aspect of Sample RTTs is not adequately addressed by the original computation method?
Signup and view all the answers
What is a potential consequence of timing out too soon in data transmission?
What is a potential consequence of timing out too soon in data transmission?
Signup and view all the answers
What does the Karn/Partridge Algorithm assume about the relationship between timeout and congestion?
What does the Karn/Partridge Algorithm assume about the relationship between timeout and congestion?
Signup and view all the answers
What improvement does the Karn/Partridge Algorithm offer over the original approach?
What improvement does the Karn/Partridge Algorithm offer over the original approach?
Signup and view all the answers
Which of the following is not a goal of the Karn/Partridge Algorithm?
Which of the following is not a goal of the Karn/Partridge Algorithm?
Signup and view all the answers
What is a consequence of not considering the variance of Sample RTTs in network computations?
What is a consequence of not considering the variance of Sample RTTs in network computations?
Signup and view all the answers
Study Notes
End-to-End Protocols
- End-to-end protocols transform host-to-host packet delivery into process-to-process communication.
- Transport protocols provide services like guaranteeing message delivery, preserving sending order, and handling large messages.
- Network limitations impact transport protocols through message dropping, reordering, duplication, and delays.
Chapter Outline
- Simple Demultiplexer (UDP)
- Reliable Byte Stream (TCP)
Chapter Goal
- Understanding demultiplexing services
- Discussing simple byte stream protocols
Common Protocol Properties
- Guarantees message delivery
- Preserves sending order and uniqueness
- Supports arbitrarily large messages
- Enables sender-receiver synchronization.
- Supports multiple application processes on each host, facilitating concurrent communication among many applications.
- Implements flow control (regulating sender data flow to receiver capacity) and congestion control (avoiding network overload).
Network Protocol Limitations
- Message dropping
- Message reordering
- Duplicate message delivery
- Limited message size
- Arbitrary message delay
Challenge for Transport Protocols
- Developing algorithms that translate network limitations into acceptable application level service quality.
Simple Demultiplexer (UDP)
- Extends host-to-host service into a process-to-process communication method.
- Adds demultiplexing layers, allowing multiple applications on a host to share the network, thus promoting concurrent use.
- Provides a connectionless and unreliable service.
- Includes protocols like TFTP, DNS, SNMP, RTP.
- UDP checksum is calculated only if the field is all zeros.
UDP Header Structure
- The header contains source and destination ports, length, and checksum fields.
- Application data follows the header.
Reliable Byte Stream (TCP)
- Provides reliable delivery, unlike UDP's connectionlessness.
- TCP is connection-oriented.
- It offers a byte stream service enabling application processes to treat data as a continuous stream, regardless of underlying packet structure.
Flow Control vs. Congestion Control
- Flow control prevents senders from overwhelming receiver capacity.
- Congestion control prevents overloading the network by regulating data injection.
End-to-End Issues
- TCP runs across the internet, not a single link.
- TCP connections vary in round-trip time (RTT).
- Packets can be reordered.
- Connection mechanisms enable communication partner resource discovery.
- Mechanisms for sender capacity learning are necessary.
TCP Segment
- TCP is byte-oriented.
- Senders write bytes, receivers read bytes from the TCP connection.
- TCP itself transmits data as segments, rather than individual bytes, which is handled by the IP layer.
- Source hosts buffer enough bytes for a packet and send as a transmit segment to destination host.
- Destination hosts empty the packet contents into a buffer, and the receiving process can read data at leisure.
- Segments are units of data exchanged between TCP peers.
TCP Header Format
- TCP header conveys crucial source/destination port details, sequence number, acknowledgment number, window size, and flags (e.g., SYN, FIN, ACK).
- Flexible Options are variable-length.
TCP Header Fields
- SrcPort & DstPort: Identify source and destination ports respectively, crucial for demultiplexing.
- Acknowledgment, SequenceNum, AdvertisedWindow: Key components of the sliding window algorithm.
- Sequence number is assigned to each data byte, facilitating order and acknowledgement of received data.
- Checksum: Data integrity verification mechanism, mirroring UDP's functionality.
TCP Header Flags
- Flags field: Used for communication control between TCP peers.
- SYN, FIN: Flags used for establishing and closing connections respectively.
- ACK: Ensures acknowledgment of received data segments.
- URG: Urgent data transmission indicator.
- PUSH: Pushes data to the receiving application.
- RST: Resets a connection.
TCP Sliding Window
- LastByteAcked, LastByteSent, LastByteWrite, NextByteExpected, and LastByteRcvd.
- Sending side components for ensuring a proper data transmission.
- Receiving side components are also essential for proper data handling and delivery.
TCP Flow Control
- Variables LastByteRcvd, MaxRecvBuffer, AdvertisedWindow, LastByteSent, and effective window parameters control flow, matching receiver capacity via advertised window.
- LastByteWritten, MaxSendBuffer: parameters crucial for efficient data transmission.
Protecting against Wraparound
- SequenceNum uses 32 bits to prevent numbering issues for extensive data transfer windows.
- The AdvertisedWindow field uses 16 bits to specify the receive buffer size.
Keeping the Pipe Full
- The 16-bit field must be large enough for reliable data pipeline operation.
- Receiver-side buffer space and bandwidth delay product interplay for optimizing throughput and addressing performance issues.
Triggering Transmission
- Factors like window size and data availability determine when TCP transmits a segment.
- Application programs dictate data writing input streams.
- TCP decides when sufficient bytes are available to form a transmission.
Nagle's Algorithm
- Optimizes data transmission by waiting for data buffers and acknowledgement packets before transmitting when network conditions are favorable to avoid needless small packets as smaller packets are less efficient to transmit than larger ones.
- Introduces a timer that triggers data transmission if enough bytes are present and no prior data has been sent.
Adaptive Retransmission
- Algorithm dynamically adjusts retransmission timeouts based on measured round-trip times to improve efficiency and responsiveness.
- The exponentially weighted moving average method computes the weighted average by giving more weight to recent observations than older ones.
- Weights help avoid the impact of outliers, improving the robustness of the timeout calculation.
Karn/Partridge Algorithm
- Improves Adaptive Retransmission by not sampling RTT during retransmission, avoiding potential inaccurate RTT estimations, focusing on avoiding inaccuracies when retransmitting packets.
- It avoids sampling RTT during retransmissions to not collect potentially erroneous data.
- It applies a double timeout after each retransmission to improve stability and robustness.
- Improves upon the original algorithm by focusing on eliminating congestion issues and not on getting an RTT directly, which involves avoiding the problems with having multiple retransmissions.
Jacobson/Karels Algorithm
- Addresses the limitations of Karn/Partridge by calculating deviation and adjusting timeouts based on varied RTT samples, enabling more intelligent prediction and less aggressive retransmissions.
TCP, Client/Server
- Highlights the various steps involved in a client-server TCP connection establishment and termination process, providing relevant details via sequence numbers and acknowledgement.
TCP, Connection Termination
- Shows the sequence of steps in TCP connection termination.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers end-to-end protocols that facilitate process-to-process communication over host-to-host packet delivery. Topics include UDP demultiplexing and TCP reliable byte stream protocols, alongside their properties like message delivery guarantees and congestion control. Test your understanding of how these transport protocols work to achieve effective data communication.
