Linux shaping packet loss

Tony Finch dot at dotat.at
Tue Dec 8 15:47:20 UTC 2009


On Tue, 8 Dec 2009, Joe Abley wrote:
>
> I find there is a lot of hard-coded wisdom that hard-coded speed duplex
> are the way to avoid pain.

That was definitely true in the mid-to-late 1990s.

> The last time I saw anybody do a modern survey of switches, routers and
> hosts, however, it seemed like the early interop problems with autoneg
> on FE really don't exist today, and on balance there are probably more
> duplex problems caused by hard-configured ports that are poorly
> maintained in the heat of battle than there are because autoneg is
> flaky.

Yes. The autoneg specification was fixed in 1998 so modern kit should
interoperate properly.

> I've also heard people say that whatever you think about autoneg in Fast
> Ethernet, on Gigabit and 10GE interfaces it's pretty much never the
> right idea to turn autoneg off.

Autoneg is a required part of the gig E specification so you'd only be
causing yourself trouble by turning it off. (I don't know if it'll also
break automatic MDI/MDI-X (crossover) configuration, for an example of
something that's nice to have.)

Tony.
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