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From: James Carlson <carlsonj@workingcode.com>
To: Richard Hartmann <richih.mailinglist@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	linux-ppp@vger.kernel.org
Subject: Re: [Patch] fix packet loss and massive ping spikes with PPP 	multi-link
Date: Fri, 26 Mar 2010 17:04:24 +0000	[thread overview]
Message-ID: <4BACE918.7020508@workingcode.com> (raw)
In-Reply-To: <v2v2d460de71003260939w4877df7em9e3084a315b0962f@mail.gmail.com>

Richard Hartmann wrote:
> Also, I am not sure if it would not be better to default to no
> fragmentation and enable it optionally. I am aware that changing default
> behaviour is always a bit of a problem but to the best of my knowledge
> enabling fragmentation is a bug in any and all real-world applications.

It worked well and was enabled by default on all the Bay Networks
equipment I used ~15 years ago.  And I know for certain that we tested
with other gear (Ascend and Clam, probably) that did it right.

If it works with the equipment you're using, it's a useful feature in
that it can balance out the latencies among the links, resulting in much
lower overall latency observed by higher layers -- especially so on
lower-speed links where MP is more likely to be used.  Without it,
you're left either waiting for the one slow link choking on a big packet
to catch up, or (worse) disabling the sequence headers altogether,
resulting in reordering unless you're really "clever."

It's a darned shame that lame implementations would force a change in
the default ...

-- 
James Carlson         42.703N 71.076W         <carlsonj@workingcode.com>

WARNING: multiple messages have this Message-ID (diff)
From: James Carlson <carlsonj@workingcode.com>
To: Richard Hartmann <richih.mailinglist@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	linux-ppp@vger.kernel.org
Subject: Re: [Patch] fix packet loss and massive ping spikes with PPP 	multi-link
Date: Fri, 26 Mar 2010 13:04:24 -0400	[thread overview]
Message-ID: <4BACE918.7020508@workingcode.com> (raw)
In-Reply-To: <v2v2d460de71003260939w4877df7em9e3084a315b0962f@mail.gmail.com>

Richard Hartmann wrote:
> Also, I am not sure if it would not be better to default to no
> fragmentation and enable it optionally. I am aware that changing default
> behaviour is always a bit of a problem but to the best of my knowledge
> enabling fragmentation is a bug in any and all real-world applications.

It worked well and was enabled by default on all the Bay Networks
equipment I used ~15 years ago.  And I know for certain that we tested
with other gear (Ascend and Clam, probably) that did it right.

If it works with the equipment you're using, it's a useful feature in
that it can balance out the latencies among the links, resulting in much
lower overall latency observed by higher layers -- especially so on
lower-speed links where MP is more likely to be used.  Without it,
you're left either waiting for the one slow link choking on a big packet
to catch up, or (worse) disabling the sequence headers altogether,
resulting in reordering unless you're really "clever."

It's a darned shame that lame implementations would force a change in
the default ...

-- 
James Carlson         42.703N 71.076W         <carlsonj@workingcode.com>

  parent reply	other threads:[~2010-03-26 17:04 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-26 15:50 [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-03-26 15:50 ` Richard Hartmann
2010-03-26 15:58 ` [Patch] fix packet loss and massive ping spikes with PPP Alan Cox
2010-03-26 16:02   ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Alan Cox
2010-03-26 16:33   ` [Patch] fix packet loss and massive ping spikes with PPP Joe Perches
2010-03-26 16:33     ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Joe Perches
2010-03-26 16:39   ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-03-26 16:39     ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-03-26 16:39     ` Richard Hartmann
2010-03-26 16:59     ` [Patch] fix packet loss and massive ping spikes with PPP David Miller
2010-03-26 16:59       ` [Patch] fix packet loss and massive ping spikes with PPP multi-link David Miller
2010-03-26 17:04       ` [Patch] fix packet loss and massive ping spikes with PPP David Miller
2010-03-26 17:04         ` [Patch] fix packet loss and massive ping spikes with PPP multi-link David Miller
2010-03-26 17:04     ` James Carlson [this message]
2010-03-26 17:04       ` James Carlson
2010-03-26 16:59   ` Alexander E. Patrakov
2010-03-26 17:00     ` Alexander E. Patrakov
2010-03-26 17:04     ` [Patch] fix packet loss and massive ping spikes with PPP Alan Cox
2010-03-26 17:04       ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Alan Cox
2010-03-31 10:03       ` Ben McKeegan
2010-03-31 10:03         ` Ben McKeegan
2010-05-29  2:16         ` [Patch] fix packet loss and massive ping spikes with PPP Paul Mackerras
2010-05-29  2:16           ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Paul Mackerras
2010-05-29  9:06           ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-05-29  9:06             ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-05-29  9:06             ` Richard Hartmann
2010-05-31 13:39           ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-05-31 13:39             ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-05-31 13:39             ` Richard Hartmann
2010-05-31 16:20           ` Ben McKeegan
2010-05-31 16:20             ` Ben McKeegan
2010-06-02 14:55             ` Ben McKeegan
2010-06-02 14:55               ` Ben McKeegan
2010-06-02 15:04               ` [PATCH] ppp_generic: fix multilink fragment sizes Ben McKeegan
2010-06-02 15:04                 ` Ben McKeegan
2010-06-02 15:17                 ` Paoloni, Gabriele
2010-06-02 15:17                   ` Paoloni, Gabriele
2010-06-02 15:31                   ` David Miller
2010-06-02 15:31                     ` David Miller
2010-06-02 15:55                   ` Ben McKeegan
2010-06-02 15:55                     ` Ben McKeegan
2010-06-03  8:41                     ` Paoloni, Gabriele
2010-06-03  8:41                       ` Paoloni, Gabriele
2010-06-03  9:14                       ` Ben McKeegan
2010-06-03  9:14                         ` Ben McKeegan
2010-11-08 14:05               ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-11-08 14:05                 ` Richard Hartmann
2010-11-15 12:07                 ` Richard Hartmann
2010-11-15 12:07                   ` Richard Hartmann
2010-06-01 10:20           ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-06-01 10:20             ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-06-01 10:20             ` Richard Hartmann
2010-06-01 11:18             ` Ben McKeegan
2010-06-01 11:18               ` Ben McKeegan
2010-06-01 11:28               ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-06-01 11:28                 ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-06-01 11:28                 ` Richard Hartmann
2010-06-01 22:15                 ` [Patch] fix packet loss and massive ping spikes with PPP David Miller
2010-06-01 22:15                   ` [Patch] fix packet loss and massive ping spikes with PPP multi-link David Miller
2010-03-31  9:01 ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-03-31  9:01   ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-03-31  9:01   ` Richard Hartmann
2010-05-25  9:52 ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-05-25  9:52   ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-05-25  9:52   ` Richard Hartmann
2010-05-25 10:18 ` walter harms
2010-05-25 14:58 ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-05-25 17:30 ` [Patch] fix packet loss and massive ping spikes with PPP multi-link walter harms
2010-05-26  8:47   ` [Patch] fix packet loss and massive ping spikes with PPP Richard Hartmann
2010-05-26  8:47     ` [Patch] fix packet loss and massive ping spikes with PPP multi-link Richard Hartmann
2010-05-26  8:47     ` Richard Hartmann
2010-05-28  7:28     ` walter harms
2010-05-28  7:28       ` walter harms

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