Common causes of performance problems and outages

: In roughly the order

: 1. Network Engineers (What's this command do?)
: 2. Power failures (What's this switch do?)
: 3. Cable cuts (Backhoes, enough said)
: 4. Hardware failures (What's that smell?)
: 5. Congestion (More Bandwidth! Captain, I'm giving you all she's got!)
: 6. Attacks (malicious, you know who you are)
: 7. Software bugs (Your call is very important to us....)

Very much disagree. Or at least, separate performance and outages.


(Tie for 1st):

1) Shitty software from Major Router Vendors (and everyone else)
1) Misconfiguration
   a) Often caused by shitty/easy to fumble CLIs from Major Router Vendors
2) Attacks
3) Power failures
4) Cable cuts
5) (distant)Hardware failure

Performance has been covered; the only real broadband is Universities,
and relatively few transit networks can get to network large and small well.


In case folks are interested....

Craig and I did some work in this area some years ago...

Our findings appeared in FTCS 99 and are available at (this
requires digital library access). I also have a pointer to the U-M
techreport version at

We have continued to collect more data on this and are in the process of
putting together our follow-up. It should be out soon.

We'd love to get more community input and more sources of data if folks
are willing to participate in our further studies...


-abha :wink: