Network interface failure detection
becker at scyld.com
Fri Mar 15 15:24:04 PST 2002
On Fri, 15 Mar 2002, lakshmi wrote:
> Does anybody know about a means by which
> it can be found out whether a network
> interface card has failed or somebody has
> pulled out the ethernet cable?
Not in general.
You can use 'mii-diag'
to find if you have lost link beat, but if the NIC has suffered a
hardware failure the status information is likely to be invalid.
> For example, there is a routing socket API
> using which it can be found if a route was
> added or not.
That's a different question: you can find the current routing
information in the same way that 'route' does. But that might not tell
you if e.g. BGP is still working.
> Similarly will the IP layer or the data link
> layer report some sort of an indication of
> the ethernet card fails? Is it possible to
> detect at the IP layer or at the data link
> layer if the ethernet cable was pulled out?
That's what 'mii-diag' will tell you:
presario$ mii-diag eth0
Basic registers of MII PHY #1: 1000 7829 0022 1720 01e1 45e1 0007 2001.
The autonegotiated capability is 01e0.
The autonegotiated media type is 100baseTx-FD.
Basic mode control register 0x1000: Auto-negotiation enabled.
Basic mode status register 0x7829 ... 782d.
Link status: previously broken, but now reestablished.
Your link partner advertised 45e1: Flow-control 100baseTx-FD 100baseTx 10baseT-FD 10baseT, w/ 802.3X flow control.
End of basic transceiver informaion.
Also check out the "--status" flag, which likely does exactly what you
Donald Becker becker at scyld.com
Scyld Computing Corporation http://www.scyld.com
410 Severn Ave. Suite 210 Second Generation Beowulf Clusters
Annapolis MD 21403 410-990-9993
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