[Techtalk] ping -s and mtu size

[Jean-Daniel Pauget]

On Sun, Jul 08, 2007 at 01:26:33PM -0700, Carla Schroder wrote:
> hey all,
> 
> Is the ping -s command something that is useful in the real world? The only 
> times I've heard of MTU size problems was when a game dev thought he could 
> use 10,000 byte packets or something equally nuts, and of course TCP broke 
> them up into smaller fragments, which horked game performance.

    mtu size problems aren't uncommon when tunneling, and event more
    frequent, when using ppp over ethernet.

> Suppose you're running ping -s and you carefully increase the size until you 
> start seeing dropped packets. Then what? how do you figure out what is 
> causing the problem?

    at least it may give you hint ? :)

    now -s is also usefull when -carefully- testing a lan : a decent lan
    shouldn't drop any packet when using flood ping, any hardware woe is
    very often detected by carefully checking where packets tend to be
    lost. on fast ethernets, gigabyte ethernet, combining -s with -f helps.

    this lead me to one question : anyone tested jumbo-sized packets with
    linux around there ?

--
    Jean-Daniel Pauget