TransAtlantic Cable Break

Leo Bicknell bicknell at
Sat Jun 23 15:21:27 UTC 2007

In a message written on Fri, Jun 22, 2007 at 11:56:32AM -0400, Sean Donelan wrote:
> Is paying for "protected circuits" actually worth it.  Or are you better 
> off just buying two circuits and using both during normal conditions. 
> Use switching at layer 3 to the remaining circuit during abnormal 
> conditions.  Most of the time, you get twice the capacity for only twice
> the price instead of a "protected circuit" where you only get the once 
> the capacity for twice the price.

Sorry, it doesn't work like that.  I do happen to believe rather
than get a single SONET/WDM protected 10G Wave you are better off
getting two unprotected 10G waves and plugging them into your
devices, and let layer 3 routing take over.  It generally saves a
good bit of cost, and it helps you keep the cable system honest.
You know when there is an outage, no way to hide it from you.

However, if you put 15G down your "20G" path, you have no redundancy.
In a cut, dropping 5G on the floor, causing 33% packet loss is not
"up", it might as well be down.

If your redundancy solution is at Layer 3, you have to have the
policies in place that you don't run much over 10G across your dual
10G links or you're back to effectively giving up all redundancy.

       Leo Bicknell - bicknell at - CCIE 3440
        PGP keys at
Read TMBG List - tmbg-list-request at,
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: not available
URL: <>

More information about the NANOG mailing list