Cisco ASA - IP Addressing

Hello,

I am setting up my network on a limited budget and have the internal network, hooked to an ISA Server, hooked to a Cisco ASA, hooked to a Cisco 1800 Series router, hooked to an Internet T1. My question is, does the ASA segment the network? In other words, are there two different netowrks, one on each side of the ASA?

something like:

Internal Network 1.1.1.0/24 ------- 1.1.1.1/24 ISA Box 1.1.2.1/24

--------- 1.1.2.2/24 Cisco ASA 1.1.3.1/24 --------- 1.1.3.2/24 Cisco

or is the ASA like a switch where it is a part of a broadcast domain and not segmenting it?

Also, do I need crossover cables to hook the ISA box to the ASA and the ASA to the router?

Thanks.