Let’s Get Simple

A picture of a mess of wiresIn the summer of 2004 I gave an invited talk at the USENIX Technical Symposium entitled “How Do I Manage All Of This?”  It was a plea to the academics that they ease off of new features and figure out how to manage old ones.  Just about anything can be managed if you spend enough time.  But if you have enough of those things you won’t have enough time.  It’s a simple care and feeding argument.  When you have enough pets you need to be efficient about both.  Computers, applications, and people all require care and feeding.  The more care and feeding, the more chance for a mistake.  And that mistake can be costly.  According to one Yankee Group study in 2003, between thirty and fifty percent of all outages are due to configuration errors.  When asked by a reporter what I believed the answer was to dealing with complexity in the network, I replyed simply, “Don’t introduce complexity in the first place.”

It’s always fun to play with new toys.  New toys sometimes require new network features.  And sometimes those features are worth it.  For instance, the ability to consolidate voice over data has brought a reduction in the amount of required physical infrastructure.  The introduction of wireless has meant an even more drastic reduction.  In those two cases, additional configuration complexity was likely warranted.  In particular you’d want to have some limited amount of quality-of-service capability in your network.

Franciscan friar William of Ockham first articulated a principle in the 14th century that all other things being equal, the simplest solution is the best.  We balance that principle with a quote from Einstein who said, “Everything should be made as simple as possible, but not simpler.”  Over the next year I will attempt to highlight examples of where we have violated both of these statements, because they become visible in the public press.

Until then, ask yourself this: what functionality is running on your computer right now that you neither need nor want?  That very same functionality is a potential vulnerability.   And what tools reduce complexity?  For instance, here is some netstat output:

% netstat -an|more
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:993             0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:995             0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:587             0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:110             0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN
tcp        0      0 127.0.0.1:2544          0.0.0.0:*               LISTEN
tcp        0      0 127.0.0.1:817           0.0.0.0:*               LISTEN
udp        0      0 0.0.0.0:32768           0.0.0.0:*
udp        0      0 127.0.0.1:53            0.0.0.0:*
udp        0      0 0.0.0.0:69              0.0.0.0:*
udp        0      0 0.0.0.0:111             0.0.0.0:*
udp        0      0 0.0.0.0:631             0.0.0.0:*
udp        0      0 127.0.0.1:123           0.0.0.0:*
udp        0      0 0.0.0.0:123             0.0.0.0:*
udp        0      0 :::32769                :::*
udp        0      0 fe80::219:dbff:fe31:123 :::*
udp        0      0 ::1:123                 :::*
udp        0      0 :::123                  :::*

It’s difficult for an expert all of this stuff.  Heaven help all of us who aren’t experts.  So what do we do?  We end up running more programs to identify what we were running.  In other words?  That’s right.  Additional complexity.  What would have happened if we simply had the name of the program output with that line?  This is what lsof does, and why it is an example of reducing complexity through innovation.  Here’s a sample:

COMMAND     PID    USER   FD   TYPE DEVICE SIZE NODE NAME
xinetd     3837    root    5u  IPv4  10622       TCP *:pop3 (LISTEN)
xinetd     3837    root    8u  IPv4  10623       TCP *:pop3s (LISTEN)
xinetd     3837    root    9u  IPv4  10624       UDP *:tftp
named      3943   named   20u  IPv4  10695       UDP localhost:domain
named      3943   named   21u  IPv4  10696       TCP localhost:domain (LISTEN)
named      3943   named   24u  IPv4  10699       UDP *:filenet-tms
named      3943   named   25u  IPv6  10700       UDP *:filenet-rpc
named      3943   named   26u  IPv4  10701       TCP localhost:953 (LISTEN)
named      3943   named   27u  IPv6  10702       TCP localhost:953 (LISTEN)
ntpd       4026     ntp   16u  IPv4  10928       UDP *:ntp
ntpd       4026     ntp   17u  IPv6  10929       UDP *:ntp
ntpd       4026     ntp   18u  IPv6  10930       UDP localhost:ntp
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