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Re: [lwip-users] Handling sudden disappearance of network i/f
From: |
Kieran Mansley |
Subject: |
Re: [lwip-users] Handling sudden disappearance of network i/f |
Date: |
Mon, 25 Sep 2006 13:42:33 +0100 |
On Mon, 2006-09-25 at 14:29 +0200, Janusz U. wrote:
> isn't the TCP keep alive responsible for that? I have similar problem with
> PPP. Link failed in middle of physical connection and lwIP does not detect
> the situation. All other systems have timeouts!
TCP keep-alives are a "MAY" rather than "MUST" or even "SHOULD" part of
the TCP specification:
http://www.freesoft.org/CIE/RFC/1122/114.htm
but lwIP does include support for them, both as a sender and receiver of
such probes.
However, to be useful, the probes must be enabled on that connection - I
think the default is "off", but haven't checked, and the connection must
be idle for a certain time before the probe is sent, and this is a long
time by default - something like an hour or two. The times can be
configured with socket options if you're using the sockets API.
They're not designed for detecting and responding rapidly to a sudden
physical layer death, more for cleaning up connections that have been
idle and no response received to the probes for a long time.
Kieran
- [lwip-users] Handling sudden disappearance of network i/f, clive, 2006/09/18
- Re: [lwip-users] Handling sudden disappearance of network i/f, Kieran Mansley, 2006/09/19
- Re: [lwip-users] Handling sudden disappearance of network i/f, Clive Wilson, 2006/09/20
- Re: [lwip-users] Handling sudden disappearance of network i/f, Kieran Mansley, 2006/09/21
- [lwip-users] LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);, Mumtaz Ahmad, 2006/09/21
- Re: [lwip-users] LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);, Kieran Mansley, 2006/09/21
- Re: [lwip-users] LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);, Mumtaz Ahmad, 2006/09/22
- Re: [lwip-users] Handling sudden disappearance of network i/f, Pedro Alves, 2006/09/25
- Re: [lwip-users] Handling sudden disappearance of network i/f, Janusz U., 2006/09/25
- Re: [lwip-users] Handling sudden disappearance of network i/f,
Kieran Mansley <=
- Re: [lwip-users] Handling sudden disappearance of network i/f, Janusz U., 2006/09/25
- Re: [lwip-users] Handling sudden disappearance of network i/f, Janusz U., 2006/09/25
- Re: [lwip-users] Handling sudden disappearance of network i/f, Kieran Mansley, 2006/09/25
- Re: [lwip-users] Handling sudden disappearance of network i/f, Janusz U., 2006/09/25
- Re: [lwip-users] Handling sudden disappearance of network i/f, Janusz U., 2006/09/25
- Re: [lwip-users] Handling sudden disappearance of network i/f, Kieran Mansley, 2006/09/26
- Re: [lwip-users] Handling sudden disappearance of network i/f, Janusz U., 2006/09/26
- Re: [lwip-users] Handling sudden disappearance of network i/f, Kieran Mansley, 2006/09/26
- Re: [lwip-users] Handling sudden disappearance of network i/f, Janusz U., 2006/09/26
- Re: [lwip-users] Handling sudden disappearance of network i/f, Janusz U., 2006/09/26