Subject: Re: [PATCHv2 net-next 0/4] Small fix for TCP PMTU

From: Fan Du <[email-masked]>
Date: Fri, 27 Feb 2015 13:37:44 +0800

于 2015年02月26日 21:40, David Laight 写道:
> From: Fan Du
>> >This patchset performs some small fix and enhancement
>> >for current TCP PMTU as per RFC4821 with below changes:
>> >
>> >Patch1/4: Set probe mss base to 1024 Bytes per RFC4821
>> >Patch2/4: Do not double probe_size for each probing,
>> >           use a simple binary search to gain maximum performance.
>> >Patch3/4: When it comes to blackhole detection, shrink current
>> >	  mss for next probing.
>> >Patch4/4: Create a probe timer to detect enlarged path MTU.
> Isn't the most likely problem PPPoE blackholes?
No.

It's used to probe a optimal pmtu value for vxlan tunnel when ICMP message
is not available. Refer patch2/4 for test summary.

> Where a reduction of the PMTU from 1500 to (IIRC) 1492 is
> all that is required?
>
> Would seem appropriate to test that value reasonable quickly.