Re: Odd TCP ECN related bahavior

2019-06-24 Thread Rodney W. Grimes
> 
> Hi all,
> 
> I am not on this mailing list. So, all responses should be sent
> to my personal address.
> 
> I just noticed somewhat confusing network behavior when I was
> using wireshark to understand why certain connections have been
> unexpectedly slow.
> 
> My 11.3 stable (latest update 2019-06-23) seems to do this
> according to wireshark...
> 
>  ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)

You only show 1 packet, and without the type of that packet
I can not tell if this is an error in the code or simply
that you captured one of the packets that does not marked
with ECN bits even in an ECN flow

Note also that ECN is negotiated on a per TCP connection,
not on every single packet.  

> 
> My system has this set, though...
> 
> net.inet.tcp.ecn.enable: 1

So ecn should be negotiated in both directions.

> 
> At the same time the peer system was reporting ECN capability...
> 
>  ..10 = Explicit Congestion Notification: ECN-Capable Transport 
> codepoint '10' (2)
> 
> Apparently increasing the value in...
> 
> net.inet.tcp.ecn.maxretries
> 
> doesn't help.
> 
> What should I make of this? Is the ECN implementation in 11.3 somehow
> faulty or is this something more down to earth?

If it is I would certainly like to now asap,

> --jau
-- 
Rod Grimes rgri...@freebsd.org
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Odd TCP ECN related bahavior

2019-06-24 Thread Jukka A. Ukkonen



Hi all,

I am not on this mailing list. So, all responses should be sent
to my personal address.

I just noticed somewhat confusing network behavior when I was
using wireshark to understand why certain connections have been
unexpectedly slow.

My 11.3 stable (latest update 2019-06-23) seems to do this
according to wireshark...

 ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)

My system has this set, though...

net.inet.tcp.ecn.enable: 1

At the same time the peer system was reporting ECN capability...

 ..10 = Explicit Congestion Notification: ECN-Capable Transport 
codepoint '10' (2)


Apparently increasing the value in...

net.inet.tcp.ecn.maxretries

doesn't help.

What should I make of this? Is the ECN implementation in 11.3 somehow
faulty or is this something more down to earth?


--jau
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