MII Link Status Not OK >>> What does this mean and any fixes?

[MRSG]

I have been receiving this 'MII Link Status Not OK' message in syslog for a couple of night's for lan0 and lan1. Please see extract below::

lan0 failed
Nov 5 07:20:58 rtv01 cmcld: Subnet 171.30.132.0 switched from lan0 to lan1
Nov 5 07:20:58 rtv01 cmcld: lan0 switched to lan1
Nov 5 07:20:58 rtv01 cmcld: lan1 failed
Nov 5 07:20:58 rtv01 cmcld: Subnet 171.30.132.0 down
Nov 5 07:20:58 rtv01 cmcld: All cluster monitoring LAN interfaces have failed
Nov 5 07:21:58 rtv01 cmcld: lan1 recovered
Nov 5 07:21:58 rtv01 cmcld: Subnet 171.30.132.0 up
Nov 5 07:21:58 rtv01 cmcld: Cluster monitoring LAN(s) have recovered
Nov 5 07:22:02 rtv01 cmcld: lan0 recovered
Nov 5 07:21:20 rtv01 vmunix: btlan6: NOTE: MII Link Status Not OK - Check Cable
Connection to Hub/Switch at 0/0/0....
Nov 5 07:22:02 rtv01 above message repeats 2 times
Nov 5 07:22:02 rtv01 cmcld: Subnet 171.30.132.0 switched from lan1 to lan0
Nov 5 07:22:02 rtv01 cmcld: lan1 switched to lan0


Please can anyone explain what causes this and how can it be fixed online? Thanks.

[S.K. Chan · Accepted solution]

From Knowledge Base ...

MII stands for Media Independent Interface. This is the interface between
your 10/100MB ethernet MAC or the repeater/switch port, and the DP83840A. The
DP83840A is a physical layer device designed for easy implementation of 10/100
MB ethernet LANs. It interfaces to the PMD sublayer through National
Semiconductor's DP83223 Twisted Pair Transceiver, and to the MAC layer through
a Media Independent Interface (MII), ensuring interoperability between products
from different vendors.

The DP83840A when Auto-Negotiating with a 100 Mb/s link partner that is sending
out 100 Mb/s scrambled idles can, for specific cable lengths, approximately 35
to 41 meters or equivalent attenuation, misinterpret the 100 Mb/s scrambled
idles as FLP???s (Fast Link Pulses), thereby causing a false MLF (Multiple Link
Fault) condition which hangs the Auto-Negotiation process (No link established).
This problem only occurs with the above scenario and does not affect other
methods of linking such as Auto-Negotiating to a 10 Mb/s link partner, Auto-
Negotiating to a Auto-Negotiation link partner, forcing the DP83840A into 100
Mb/s mode and linking to a 100 Mb/s link partner, and forcing the DP83840A into
10 Mb/s mode and linking to a 10 Mb/s link partner.

Hence the error message "MII Link Status Not OK."


The solution? For existing products using the DP83840A the following can be
done to work around the problem:

a) Manually configure the system using the DP83840A into 100 Mb/s mode through
software. (turn off autonegotiation at the switch and on the card, using the
appropriate configuration file)

b) Modify software driver to detect fault condition (apply the latest NIC
patch


For more information on this, see the whitepaper located at
http://docs.hp.com/hpux/onlinedocs/netcom/autonegotiation.pdf

[Sanjay_6]

Hi,

Turn autonegotiation off on the server side as well as on the switch side. Set the netword and the Switch port to 100Mbps, fixed , full duplex.

you may also consider looking for some network patch which you need on the system.

Hope this helps

Regds

[John Waller]

I am concerned that both LAN0 and LAN1 failed. If I understand the situation correctly you are running with a MC/ServiceGuard cluster. Do you have both your LAN's plugged into the same hub or switch , also do you get the same errors at the same times on your alternate node. Ideally you should have LAN0 and LAN1 on any machine within the cluster plugged into different switches or hubs. This will not help you with you MII Link Down messages but it may help stop the package closing down or switching because the subnet is down. I personally believe that this is a hub or switch problem as both cards seem to fail at the same time.

[harry d brown jr]

Your networking people aren't rebooting your routers/hubs at night are they?

live free or die
harry

[MRSG]

thanks