technology:tcp protocol

  • Bufferbloat: The hidden cause of slow Internet and how to fix it

    A good and lengthy article pointing to the fact that awareness of bufferbloat is still not widespread.

    We strongly recommend that network operators study the vast amount of research already available on the topic of bufferbloat. Then, at critical network connections such as wireless and mobile access points, we need to test for bufferbloat. You will probably want to have the data from these tests to talk with your service provider or wireless access point vendor.

    What exactly is buffer bloat?
    The issue is closely tied to how the TCP protocol operates and how network buffers are managed. Even though there is a widespread belief that dropping packets in the Internet is always a bad thing, the truth is that dropping packets is absolutely essential to the proper operation of TCP.

    In an attempt to reduce packet loss in the internet, network operators, developers, and engineers have increased the size of network buffers many times over. This increases latency but has little effect on throughput. Consequently, critical small packets such as those in VoIP, DNS, and TCP ‘acks’ can become trapped in the buffers behind much larger packets from file transfers and other bulk transfers, such as adaptive bit rate video.

    Who is most affected by this phenomenon?

    Anyone who is actively browsing or using search engines. Also, anyone who is using real-time applications like voice or video. An example would be employees working from home, on the road in hotels or at Wi-Fi hot spots. Our research showed that hotels and Wi-Fi cafes are prone to very bad bufferbloat issues.

    What kind of traffic is affected?

    Traffic flowing on links which have high-bandwidth utilization in the opposite direction will deteriorate. Applications using small packets such as VoIP, DNS, and ARP can also suffer. The impact on VoIP will be increased latency and jitter. DNS queries may be returned in two to eight times the normal response time.

    What is buffer bloat’s impact on TCP operation?
    Understanding how TCP operates reveals why buffer bloat is a problem. ers.
    This is nicely explained in the article by explaining the slow start en TCP’s Congestion Control algorithm, as well how the problem could be tackled with techniques such as CoDel, or Controlling Queue Delay, and fq-Codel, which seems more effective than RED or WRED

    http://www.networkworld.com/article/3107744/internet/the-hidden-cause-of-slow-internet-and-how-to-fix-it.html
    Backup copy of the article: https://www.docdroid.net/file/download/srkf7eW/the-hidden-cause-of-slow-internet-and-how-to-fix-it-network-world.pdf

    #bufferbloat