For increased reliability I want to have both cable and dsl. Is it hard to switch back and forth with a laptop

Answer 1

To avoid the issue with re-IPing the laptop when one or the other connection craps out, you can opt to get a dual (or more) port WAN router. Edimax sells some (http://www.edimax.com/html/english/products/BR-6524.htm). I am not sure how they keep track of the connectivity breaking more than one hop away...maybe some kind of object tracking.

Answer 2

For Cable you need Cable Modem.
& different modem for DSL .
You may have to change the cable
every time you switch to cable or dsl. or
if the cables connect to different sockets ,
switch off the system you do not need.
I have both dialup and adsl connected
always as one connector is Rj45 and
another ordinary Phone cable for dialup.
in my laptop.