Difficulty recovering from DSL loss of sync

I run Fedora 7 and KDE. I use Verizon DSL with a Westell 6100 E90 modem.
PPPoE function is provided by the modem. When I lose my DSL connection
(loss of sync), the only way so far I've been able to regain my Internet
connection is to force a reboot without cleanly shutting down my current
session. I suspect this isn't normal, but I don't know where to even
begin to debug.

I believe that when I lose DSL sync, I should be able to regain my
Internet connection by doing the following:

1. power off the modem (powered off for at least two minutes)
2. deactivate eth0
3. power up the modem (wait at least one minute for modem LED to display
sync)
4. activate eth0

I've tried doing this from both the GUI (K -> System -> Network Device
Control -> deactivate eth0) and from the command line: (ifconfig eth0
down). In both cases the command hangs. There is no progress for over
thirty minutes.

When I lose DSL sync, ifconfig reports eth0 "UP" but not "RUNNING".

If I try to cleanly shut down Fedora (K -> logout -> Restart computer),
a hang occurs at "shutting down interface eth0". This hang persists for
over ten minutes.


Allen Weiner

On Mon, 13 Aug 2007 14:19:18 GMT Allen Weiner <(E-Mail Removed)> wrote:
| I run Fedora 7 and KDE. I use Verizon DSL with a Westell 6100 E90 modem.
| PPPoE function is provided by the modem. When I lose my DSL connection
| (loss of sync), the only way so far I've been able to regain my Internet
| connection is to force a reboot without cleanly shutting down my current
| session. I suspect this isn't normal, but I don't know where to even
| begin to debug.
|
| I believe that when I lose DSL sync, I should be able to regain my
| Internet connection by doing the following:
|
| 1. power off the modem (powered off for at least two minutes)
| 2. deactivate eth0
| 3. power up the modem (wait at least one minute for modem LED to display
| sync)
| 4. activate eth0
|
| I've tried doing this from both the GUI (K -> System -> Network Device
| Control -> deactivate eth0) and from the command line: (ifconfig eth0
| down). In both cases the command hangs. There is no progress for over
| thirty minutes.
|
| When I lose DSL sync, ifconfig reports eth0 "UP" but not "RUNNING".

It has lost data link, much like unplugging the cable.


| If I try to cleanly shut down Fedora (K -> logout -> Restart computer),
| a hang occurs at "shutting down interface eth0". This hang persists for
| over ten minutes.

The PPP session may be hanging this. PPP I believe is still handled in
kernel space (Linus: we know you like to move logic out to user space,
could you please do this with PPP soon). Some script started that up.
In Fedora it's probably part of the network scripts. Hopefully killing
the process that opened the socket and handed PPP handling over to the
kernel should reset it. Reset or kill PPP before trying to reset eth0.
It may not be necessary to reset eth0 if PPP can be reset. Or it may
also be necessary to unplug the ethernet cable from one end or the other
as part of the hardware resets.

--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2007-08-14-(E-Mail Removed) |
|------------------------------------/-------------------------------------|

phil-news-(E-Mail Removed) wrote:
> On Mon, 13 Aug 2007 14:19:18 GMT Allen Weiner <(E-Mail Removed)> wrote:
> | I run Fedora 7 and KDE. I use Verizon DSL with a Westell 6100 E90 modem.
> | PPPoE function is provided by the modem. When I lose my DSL connection
> | (loss of sync), the only way so far I've been able to regain my Internet
> | connection is to force a reboot without cleanly shutting down my current
> | session. I suspect this isn't normal, but I don't know where to even
> | begin to debug.
> |
> | I believe that when I lose DSL sync, I should be able to regain my
> | Internet connection by doing the following:
> |
> | 1. power off the modem (powered off for at least two minutes)
> | 2. deactivate eth0
> | 3. power up the modem (wait at least one minute for modem LED to display
> | sync)
> | 4. activate eth0
> |
> | I've tried doing this from both the GUI (K -> System -> Network Device
> | Control -> deactivate eth0) and from the command line: (ifconfig eth0
> | down). In both cases the command hangs. There is no progress for over
> | thirty minutes.
> |
> | When I lose DSL sync, ifconfig reports eth0 "UP" but not "RUNNING".
>
> It has lost data link, much like unplugging the cable.
>
>
> | If I try to cleanly shut down Fedora (K -> logout -> Restart computer),
> | a hang occurs at "shutting down interface eth0". This hang persists for
> | over ten minutes.
>
> The PPP session may be hanging this. PPP I believe is still handled in
> kernel space (Linus: we know you like to move logic out to user space,
> could you please do this with PPP soon). Some script started that up.
> In Fedora it's probably part of the network scripts. Hopefully killing
> the process that opened the socket and handed PPP handling over to the
> kernel should reset it. Reset or kill PPP before trying to reset eth0.
> It may not be necessary to reset eth0 if PPP can be reset. Or it may
> also be necessary to unplug the ethernet cable from one end or the other
> as part of the hardware resets.
>

Thanks for your reply.

It appears I may have better results using "ifup eth0" and "ifdown eth0"
instead of "ifconfig eth0 up" and "ifconfig eth0 down".

I will try this the next time I lose DSL sync. I'd like to test it
sooner by simulating a DSL loss of sync. I tried power cycling the
modem. When I restored power, my Internet connection resumed by itself.

Allen Weiner <(E-Mail Removed)> wrote:

>> The PPP session may be hanging this. PPP I believe is still handled in
>> kernel space (Linus: we know you like to move logic out to user space,
>> could you please do this with PPP soon). Some script started that up.
> It appears I may have better results using "ifup eth0" and "ifdown eth0"
> instead of "ifconfig eth0 up" and "ifconfig eth0 down".

AFAIK ifup and ifdown will run the associated scripts
in /etc/sysconfig/network-scripts on Fedora which should terminate any ppp
daemons and other such processes attached to the interface.

I'd try "killall pppd" if the interface is hanging.

--
Jamin @ Home: Chester UK -<(E-Mail Removed)>

Jamin Davis wrote:
> Allen Weiner <(E-Mail Removed)> wrote:
>
>>> The PPP session may be hanging this. PPP I believe is still handled in
>>> kernel space (Linus: we know you like to move logic out to user space,
>>> could you please do this with PPP soon). Some script started that up.
>> It appears I may have better results using "ifup eth0" and "ifdown eth0"
>> instead of "ifconfig eth0 up" and "ifconfig eth0 down".
>
> AFAIK ifup and ifdown will run the associated scripts
> in /etc/sysconfig/network-scripts on Fedora which should terminate any ppp
> daemons and other such processes attached to the interface.
>
> I'd try "killall pppd" if the interface is hanging.
>

I'm not sure pppd is active. I browsed /var/log/messages about twenty
minutes after bootup and there is nothing there referring to pppd.

PPPoE functionality is offloaded into my Westell 6100 DSL modem/router.

I'm a Linux novice. I will have to do a lot of homework, reading up on
Linux networking, so that I can learn how ppp fits in to DSL.

Allen Weiner <(E-Mail Removed)> wrote:

> I'm not sure pppd is active. I browsed /var/log/messages about twenty
> minutes after bootup and there is nothing there referring to pppd.

> PPPoE functionality is offloaded into my Westell 6100 DSL modem/router.

> I'm a Linux novice. I will have to do a lot of homework, reading up on
> Linux networking, so that I can learn how ppp fits in to DSL.

The bottom line is that there is no PPPoE (and so no pppd) running on
your Linux box. Period.

That said, the "DSL HOWTO for Linux," "section 5.3. Sync Problems"
may be useful reading:

http://www.faqs.org/docs/Linux-HOWTO...TO.html#SYNCTR

PPPoE is, after all, ADSL with a twist. But if just power cycling the
modem works for you..

The missing RUNNING seems to occur when the interface device driver
is aware that something is wrong and is unable to function properly
even though it is "UP," which I /think/ means correctly configured
ala ifconfig. Maybe someone who knows about ethernet drivers can be
more specific - I can't.

--
Clifford Kite
/* Better is the enemy of good enough. */

Clifford Kite wrote:
> Allen Weiner <(E-Mail Removed)> wrote:
>
>> I'm not sure pppd is active. I browsed /var/log/messages about twenty
>> minutes after bootup and there is nothing there referring to pppd.
>
>> PPPoE functionality is offloaded into my Westell 6100 DSL modem/router.
>
>> I'm a Linux novice. I will have to do a lot of homework, reading up on
>> Linux networking, so that I can learn how ppp fits in to DSL.
>
> The bottom line is that there is no PPPoE (and so no pppd) running on
> your Linux box. Period.
>
> That said, the "DSL HOWTO for Linux," "section 5.3. Sync Problems"
> may be useful reading:
>
> http://www.faqs.org/docs/Linux-HOWTO...TO.html#SYNCTR
>
> PPPoE is, after all, ADSL with a twist. But if just power cycling the
> modem works for you..
>
> The missing RUNNING seems to occur when the interface device driver
> is aware that something is wrong and is unable to function properly
> even though it is "UP," which I /think/ means correctly configured
> ala ifconfig. Maybe someone who knows about ethernet drivers can be
> more specific - I can't.
>

Thanks for the reference to the DSL How-to. (I've browsed it before, as
well as several other Linux networking documents. But at the time, I
wasn't focused on sync problems, so I forgot sync was discussed there.)

Power cycling the modem does not work when I lose sync. It only worked
when I was trying to simulate loss-of-sync.

Allen Weiner <(E-Mail Removed)> wrote:

>> The missing RUNNING seems to occur when the interface device driver
>> is aware that something is wrong and is unable to function properly
>> even though it is "UP," which I /think/ means correctly configured
>> ala ifconfig. Maybe someone who knows about ethernet drivers can be
>> more specific - I can't.
> Power cycling the modem does not work when I lose sync. It only worked
> when I was trying to simulate loss-of-sync.

The previous poster said there was no pppd running on your box. But it
sounds to me from what you described that when you lose sync either
from "natural causes " or by power cycling the "RUNNING" in the ifconfig
disappears (the link is UP but no pppd attached). I think the best order to
restart your link is "ifdown ppp0" - powercycle - "ifup ppp0". ifconfig
up/down doesn't run the other scripts to bring a ppp link up.

--
Jamin @ Home: Chester UK -<(E-Mail Removed)>

Jamin Davis wrote:
> Allen Weiner <(E-Mail Removed)> wrote:
>
>>> The missing RUNNING seems to occur when the interface device driver
>>> is aware that something is wrong and is unable to function properly
>>> even though it is "UP," which I /think/ means correctly configured
>>> ala ifconfig. Maybe someone who knows about ethernet drivers can be
>>> more specific - I can't.
>> Power cycling the modem does not work when I lose sync. It only worked
>> when I was trying to simulate loss-of-sync.
>
> The previous poster said there was no pppd running on your box. But it
> sounds to me from what you described that when you lose sync either
> from "natural causes " or by power cycling the "RUNNING" in the ifconfig
> disappears (the link is UP but no pppd attached). I think the best order to
> restart your link is "ifdown ppp0" - powercycle - "ifup ppp0". ifconfig
> up/down doesn't run the other scripts to bring a ppp link up.
>

Is your recommended sequence "ifdown ppp0" - powercycle - "ifup ppp0"
(as you wrote), or "ifdown eth0" - powercycle - "ifup eth0" ?

On Sun, 19 Aug 2007 03:00:27 GMT Allen Weiner <(E-Mail Removed)> wrote:

| Is your recommended sequence "ifdown ppp0" - powercycle - "ifup ppp0"
| (as you wrote), or "ifdown eth0" - powercycle - "ifup eth0" ?

Let us know which works.

--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2007-08-18-(E-Mail Removed) |
|------------------------------------/-------------------------------------|