TransAtlantic Cable Break

Sun Jun 24 12:32:48 UTC 2007

Leo Bicknell wrote:
> 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.

That really depends.  Two unprotected circuits are going to cost you
twice as much.  Typically if you're paying for protection, you're not
getting two wavelengths, you're just getting electronics protection in
the providers network; unless you've purchased the circuit "route
diverse" on separate fiber paths.  Protected in some networks doesn't
always mean "route diverse".

> 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.

I don't know if that's always true.  Case in point 802.17.  It runs
active-active in unprotected space.  While you have the extra bandwidth
and classes of service, a cut doesn't really mean you're hard down, it
all depends on the SLA's you provide to customers.  Of course anything
over the guaranteed bandwidth during failure would be classed only as
"best effort".

-- 
Robert Blayzor
INOC
rblayzor at inoc.net
http://www.inoc.net/~rblayzor/

If you unplug it fast enough, anything is hot swappable!