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[Freeipmi-devel] Re: [llnl-devel] Re: power control and BMC configuratio

From: Anand Babu
Subject: [Freeipmi-devel] Re: [llnl-devel] Re: power control and BMC configuration problem
Date: Thu, 22 Jan 2004 15:31:02 -0800
User-agent: Gnus/5.1006 (Gnus v5.10.6) Emacs/21.3 (gnu/linux)

,----[ Albert Chu <address@hidden> ]
| My debugging has shown that tiger4 BMCs never respond to ARP requests.
| When I tried to enable "BMC-generated ARP responses", the BMC gave me
| "invalid configuration option" errors.  My belief is that tiger4 BMCs
| only send out gratuitous ARPs, and it is the job of the
| switch/router/ethernet to see the gratuitous ARPs and cache the MAC
| address of the card.

I believe we are facing "OS-Absent problems with ARP" 
See IPMI 1.5 rev1.1 - Section 12.7.1 - PDF Page# 141

Possible solutions are also described in Section 12.7.2.

My recommendations:
1) Run a proxy ARP daemon. Robin mentioned you are already
running such service in your network for some switches.
2) Gratuitous ARPs

I will take a look at these commands and fix them. They are supported
by Intel's BMC. (Ian, can you take a look at this)
PDF Page# 256
- Enable BMC Generated ARP Responses
- Enable BMC Generated Gratuitous ARP Responses

,----[ Albert Chu <address@hidden> ]
| > Questions: Don't these switches cache the association?
| I'm not 100% sure.  I do know that after we halt a machine, the ARP
| cache entries in various thunder nodes are still up to date (seen
| through /sbin/arp -a) ...
You have to see the ARP table of the cisco switch.


>----- Original Message -----
>From: Anand Babu <address@hidden>
>Date: Thursday, January 22, 2004 2:45 pm
>Subject: Re: [llnl-devel] Re: power control and BMC configuration problem

> Hi Al,
> I am no switch expert, just theoretical guess.
> Condition to reproduce:
> - when kernel halts but system is ON.
> Crossover cable works: (reason)
> - because it is point to point. Any packet you drop on the network
> reaches the other end and BMC responds. (no switching or routing)
> Cause of problem:
> BMC does not respond to ARP queries after OS takes over. When OS stops
> responding to ARP requests, switch has no way to associate a MAC
> address to a port. 
> Debug:
> Cisco switch - Manually associate a MAC address to port
> Questions:
> Don't these switches cache the association?
> -ab
> >We tried the cross-over cable, and power control worked perfectly. 
> So
> >its most likely some type of switch issue.  Have you been able to
> >reproduce the problem??
> _______________________________________________
> llnl-devel mailing list
> address@hidden

Anand Babu
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