[Beowulf] tcp error: Need ideas!

Gerry Creager gerry.creager at tamu.edu
Sun Jan 25 16:04:06 EST 2009


Nifty Tom Mitchell wrote:
> On Sun, Jan 25, 2009 at 08:55:41AM -0600, Gerry Creager wrote:
> .....
>> In other words, it's not the switch.  I tend to "think out loud" to  
>> expose all possible failure modes, a process I learned at NASA/Johnson  
>> when I worked on Space Station's Medical Operations.  In manned  
>> spaceflight, you have one exercise where you sit around and try to  
>> determine everything that could possibly go wrong, and how such a  
>> failure would manifest itself.  That tends to be useful in other  
>> operations, too.
> 
> In the spirit of anything could be wacked .... 
> 
> Double check all the MAC addresss and all the ARP tables (inluding things
> like /etc/ethers and HWADDR lines in ifcfg-* and DHCP setup files.

ifcfg files all specify the MAC.  arp tables look good.  DHCP table 
assigns an address based on hard-coded MACs.  They're all there, and 
appropriate.

> Also Zero Configuration Networking (Zeroconfig) networking....
> and IPV6 could be exposing alternate logical paths for data 
> on the same switches and wires.

While IPv6 is "there" in local mode, it's not invoked.  All these 
systems are really communicating at Layer 2, since they reside on the 
same broadcast domain.  tracepath doesn't indicate any asymmetrical 
paths for the "several" I've manually looked at.

Thanks, gerry
-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University	
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.862.3983
Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX 77843
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