Enterprise IP Addressing

cycleking

Got a quick question if I may.

How does the enterprise IP scheme look like on the external side of things, (Not the private addresses i.e. 192.168x.x, 172.16.x.x, or the 10.x.x.x) But the public IP addresses. Take a fictional company ABC LLC. who has multiple sites all over the US would their IP scheme all fall into the same subnet? Or in order for all the sites to talk to one another do they create routes to the network they have been assigned by the ISP?

Site A has IP 129.11.22.33, so does that mean site B must fall within the same 129.x.x.x and they just subnet it out some how with the ISP, do they buy multiple IP addresses all with the same first octet?

Or

Site A has 129.11.22.33 and Site B has 56.85.44.11 And they have to deal with what they are given by the ISP?

How do they do it when a company has multiple sites?

Let me know if I made your head explode or if i'm confusing you.
I would like to replicate as much as possible to real world setups instead of just creating the normal 192.whatever setup.

networker050184

If you don't own your own IP space then yes you have to take what blocks the ISP gives you. Even if you own your own you won't use the same subnet across sites, but they may be subnets of the same supernet.