Tag: MSS

TIMELY

Posted on by lechuck park

With Claude
TIMELY (Transport Informed by MEasurement of LatencY)

  1. System Architecture
  • Cloud/Data Center to External Network Connection
  • TIMELY Module Process at Kernel Level
  • Bidirectional Operation Support
  • TCP Protocol Based
  1. RTT-based Traffic Control Components
  • RTT Monitoring
    • 5-tuple monitoring (Src/Dst IP, Src/Dst Port, Protocol)
    • Real-time latency measurement
  • Congestion Detection
    • Network congestion detection through RTT increases
  • Congestion Window Adjustment
    • Control of send buffer size
  • MSS-based Adjustments
    • Congestion window adjustments in MSS units
  1. Related RTT-based Technologies
  • TCP BBR
  • TCP Vegas
  • CUBIC TCP
  1. Advantages of RTT-based Control
  • Proactive congestion detection before packet loss
  • Real-time network state awareness
  • Efficient buffer management
  • Lower latency in data transmission
  • Effective bandwidth utilization
  • Better performance in high-speed networks
  1. Disadvantages of RTT-based Control
  • RTT measurement accuracy dependency
  • Complex implementation at kernel level
  • Potential overhead in RTT monitoring
  • Need for continuous RTT measurement
  • Sensitivity to network jitter
  • May require adjustments for different network environments

The TIMELY system demonstrates an efficient approach to network congestion control using RTT measurements, particularly suitable for cloud and data center environments where latency and efficient data transmission are critical. The system’s kernel-level implementation and MSS-based adjustments provide fine-grained control over network traffic, though success heavily depends on accurate RTT measurements and proper environment calibration.

TCP BBR

Posted on by lechuck park

From ChatGPT with some prompting
Overview of TCP BBR:

  • TCP BBR optimizes network performance using Bottleneck Bandwidth and Round-trip time (RTT).
  • Speed is determined by RTT.
  • Bandwidth is determined by Bottleneck Bandwidth.

Learning Process:

  • Every ACK:
    • Updates the bottleneck bandwidth.
    • Tracks the minimum observed RTT value.
  • Every RTT:
    • Adjusts the sending size (n * MSS) and the pacing rate (the rate at which data is sent).

Sending Size Update:

  • BBR continuously updates the sending size (how many MSS to send) based on the current network conditions.

In summary, TCP BBR learns the network conditions by monitoring the bottleneck bandwidth and RTT, and accordingly adjusts the sending size and pacing rate to optimize data transmission, reducing congestion and improving performance.

MSS

Posted on by lechuck park

From Claude with some prompting
This image explains the concept of Maximum Segment Size (MSS) in computer networking. MSS refers to the maximum size of the data payload that can be transmitted in a single TCP segment. The main points illustrated are:

  1. The TCP header and IP header each have a fixed size of 20 bytes.
  2. MSS is defined as the maximum size of the TCP payload within a single packet.
  3. MSS is used for TCP communication to control congestion and prevent large TCP packets at the application level.
  4. This is contrasted with the Maximum Transmission Unit (MTU) which limits packet size at the physical layer, such as in Ethernet switches.
  5. The image depicts a concept called “One Time Transfer Data Size” with 1 MTU packet being sent, followed by acknowledgment (3 DUP ACK), and then a timeout period.

The overall purpose of MSS is to manage and optimize data transmission by limiting the segment size, thereby facilitating better congestion control and efficient network performance.

MTU & MSS

Posted on by lechuck park

From Copilot with some prompting
Certainly! Let’s clarify the distinct purposes of MTU (Maximum Transfer Unit) and MSS (Maximum Segment Size):

  1. MTU (Maximum Transfer Unit):
    • Associated with Ethernet, MTU represents the maximum size of an Ethernet frame.
    • When data is transmitted over a network, it is divided into smaller packets (frames). MTU defines the largest size a frame can be.
    • If a frame exceeds the MTU, it will be fragmented by the outgoing network device.
    • MTU optimization aims to efficiently share network bandwidth.
  2. MSS (Maximum Segment Size):
    • Associated with TCP (Transmission Control Protocol), MSS controls the flow of data within a TCP session.
    • It specifies the largest amount of data that can be sent in a single TCP segment.
    • The sender determines how many MSS units are sent at a given time.
    • MSS plays a crucial role in TCP congestion control and affects the TCP window size.

In summary, MTU focuses on frame size in the Ethernet layer, while MSS governs data segmentation and flow control in the TCP layer.