pontification bloat (was 10GE TOR port buffers (was Re: 10G switch recommendaton))

George Bonser gbonser at seven.com
Sun Jan 29 22:57:53 UTC 2012

> This sounds a lot like most peoples ipv6 rationale as well.
> I'm still feeling some scars from last time Ecn was enabled in my
> hosts. Many firewalls would eat packets with. Ecn enabled.

That was, I believe, nearly 10 years ago, was it not?  

There has been considerable testing with ECN with the bufferbloat folks and I have done some myself and haven't noticed anyone blocking ECN lately.  There might still be a few corner cases out there still, but none that I have noticed.  What you will find, according to what I have read by others doing testing is that some networks will clobber the ECN bits (reset them) but pass the traffic.  These days at worst you would not be able to negotiate ECN but the traffic wouldn't be blocked.  Anyone clearing the entire DSCP byte on traffic entering their network, for example, would clobber ECN but not block the traffic.

The key thing here would be to have people NOT clear ECN bits on traffic flowing through their network to allow it to be negotiated end to end by the hosts involved in the transaction.

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