Lazy Network Usage

By Finchy ยท 9 replies
Oct 7, 2007
  1. I have a Virgin Broadband 8mb connecton, which never really achieves that.
    I thought is was just because of where i live because i'm in the furthest north-west of engand. But today in contol panel, while surfing the net, on Live MEssenger and downloading, i said that my network utilisation was peaking at only 6%.

    I was wondering why that was, and if i can boost it, im sick of low speeds

  2. Fragrant Coit

    Fragrant Coit TS Guru Posts: 363

    If you are looking at what I think you are, it's displaying 6% of the ADAPTERS limit - probably 100Mbps.

    You'll never get 8Mb download speeds, probably below 800kbps maximum, and that depends on the source as well.
  3. jobeard

    jobeard TS Ambassador Posts: 11,166   +986

    Network thruput is like the weakest link in the chain problem; ANY slowness
    ANYWHERE effects the overall thruput.

    First, ethernet is a contention system which ends up meaning only 70% efficiency is possible.
    So the wonderful 100mb card in your system at best can only run 70mb and
    no PC will ever get that hi (they're designed for network backbones, not PCs).

    Your link to the ISP is throttled by QoS software at the ISP to balance you
    against all other users AND as a means to charge for more thruput for commercial users.

    I'm getting about 4100kbs up and 410 down on my cable link, but I've also
    seen it much lower at times.

    Suggest you set your MTU to 1492 (which helps avoid fragmented packets)
    and that you avoid things like torrents as they just swamp our lowend routers.
  4. Finchy

    Finchy TS Rookie Topic Starter Posts: 353

    Thanks for the replies, the adaptor is 22mbps, its pretty old (also wireless)

    My downloads are usually between 40kbps and 90kbsp
    Uploads usually around 30kbps

    How would i go about changing my MTU (and what is MTU)?
  5. jobeard

    jobeard TS Ambassador Posts: 11,166   +986

    see this article on MTU

    I've always used the 1492 - PPPoE Broadband Connections unless on a
    dial-up line, where I set 576 :)
  6. tipstir

    tipstir TS Ambassador Posts: 2,475   +126

    Cable/Domain use: 1500 MTU (make sure Router and PCs all of them are set)
    DSL: 1492
  7. jobeard

    jobeard TS Ambassador Posts: 11,166   +986

    (TCP, IP, MTU and MSS magic numbers)
    1. 1500 The biggest-sized IP packet that can normally traverse the Internet without getting fragmented. Typical MTU for non-PPPoE, non-VPN connections.
    2. 1492 The maximum MTU recommended for Internet PPPoE implementations.
    3. 1472 The maximum ping data payload before fragmentation errors are received on non-PPPoE, non-VPN connections.
    4. 1460 TCP Data size (MSS) when MTU is 1500 and not using PPPoE.
    5. 1464 The maximum ping data payload before fragmentation errors are received when using a PPPoE-connected machine.
    6. 1452 TCP Data size (MSS) when MTU is 1492 and using PPPoE.
    7. 576 Typically recommended as the MTU for dial-up type applications, leaving 536 bytes of TCP data.
    8. 48 The sum of IP, TCP and PPPoE headers<./TD>
    9. 40 The sum of IP and TCP headers.
    10. 28 The sum of IP and ICMP headers.

    The whole object of setting an MTU value is to avoid fragmentation of packets
    and thus avoid retries (a performance issue) and packet reassembly (a security issue)

    *IF* any router in the path has MTU-Discovery active, it will reduce the actual
    packet sizes delivered to the smallest MTU in the chain so setting 1500
    is unlikely to be the actual size received anyway.
  8. Finchy

    Finchy TS Rookie Topic Starter Posts: 353

    My MTU is set at 1500, will changing to 1492 make any difference?
  9. jobeard

    jobeard TS Ambassador Posts: 11,166   +986

    no noticable, performance difference. the sole impact is to reduce packet fragmentation.
  10. Finchy

    Finchy TS Rookie Topic Starter Posts: 353

    Oh okay, thanks
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